+Lua 5.1 Reference Manual
+
+Lua 5.1 Reference Manual
++ +++ +Lua 5.1 Reference Manual +
by R. Ierusalimschy, L. H. de Figueiredo, W. Celes +
Lua.org, August 2006 +
ISBN 85-903798-3-3 +
++
+
+ +Buy a copy of this book and +help to support +the Lua project. +
+ +The reference manual is the official definition of the Lua language. +For a complete introduction to Lua programming, see the book +Programming in Lua. +
+ +start +· +contents +· +index +· +português +· +español +
+ +
+
+
+
+
+
+
+
+ +
+The given +options +(see below) +are executed and then +the Lua program in file +script +is loaded and executed. +The given +args +are available to +script +as strings in a global table named +arg. +If these arguments contain spaces or other characters special to the shell, +then they should be quoted +(but note that the quotes will be removed by the shell). +The arguments in +arg +start at 0, +which contains the string +'script'. +The index of the last argument is stored in +arg.n. +The arguments given in the command line before +script, +including the name of the interpreter, +are available in negative indices in +arg. +
+At the very start, +before even handling the command line, +lua +executes the contents of the environment variable +LUA_INIT, +if it is defined. +If the value of +LUA_INIT +is of the form +'@filename', +then +filename +is executed. +Otherwise, the string is assumed to be a Lua statement and is executed. +
+Options start with +'-' +and are described below. +You can use +'--' +to signal the end of options. +
+If no arguments are given, +then +"-v -i" +is assumed when the standard input is a terminal; +otherwise, +"-" +is assumed. +
+In interactive mode, +lua +prompts the user, +reads lines from the standard input, +and executes them as they are read. +If a line does not contain a complete statement, +then a secondary prompt is displayed and +lines are read until a complete statement is formed or +a syntax error is found. +So, one way to interrupt the reading of an incomplete statement is +to force a syntax error: +adding a +';' +in the middle of a statement is a sure way of forcing a syntax error +(except inside multiline strings and comments; these must be closed explicitly). +If a line starts with +'=', +then +lua +displays the values of all the expressions in the remainder of the +line. The expressions must be separated by commas. +The primary prompt is the value of the global variable +_PROMPT, +if this value is a string; +otherwise, the default prompt is used. +Similarly, the secondary prompt is the value of the global variable +_PROMPT2. +So, +to change the prompts, +set the corresponding variable to a string of your choice. +You can do that after calling the interpreter +or on the command line +(but in this case you have to be careful with quotes +if the prompt string contains a space; otherwise you may confuse the shell.) +The default prompts are "> " and ">> ". +
+- +load and execute the standard input as a file, +that is, +not interactively, +even when the standard input is a terminal. +
+-e stat +execute statement +stat. +You need to quote +stat +if it contains spaces, quotes, +or other characters special to the shell. +
+-i +enter interactive mode after +script +is executed. +
+-l name +call +require('name') +before executing +script. +Typically used to load libraries. +
+-v +show version information. +
+The main advantages of precompiling chunks are: +faster loading, +protecting source code from accidental user changes, +and +off-line syntax checking. +
+Precompiling does not imply faster execution +because in Lua chunks are always compiled into bytecodes before being executed. +luac +simply allows those bytecodes to be saved in a file for later execution. +
+Precompiled chunks are not necessarily smaller than the corresponding source. +The main goal in precompiling is faster loading. +
+The binary files created by +luac +are portable only among architectures with the same word size and byte order. +
+luac +produces a single output file containing the bytecodes +for all source files given. +By default, +the output file is named +luac.out, +but you can change this with the +-o +option. +
+In the command line, +you can mix +text files containing Lua source and +binary files containing precompiled chunks. +This is useful because several precompiled chunks, +even from different (but compatible) platforms, +can be combined into a single precompiled chunk. +
+You can use +'-' +to indicate the standard input as a source file +and +'--' +to signal the end of options +(that is, +all remaining arguments will be treated as files even if they start with +'-'). +
+The internal format of the binary files produced by +luac +is likely to change when a new version of Lua is released. +So, +save the source files of all Lua programs that you precompile. +
+
+-l +produce a listing of the compiled bytecode for Lua's virtual machine. +Listing bytecodes is useful to learn about Lua's virtual machine. +If no files are given, then +luac +loads +luac.out +and lists its contents. +
+-o file +output to +file, +instead of the default +luac.out. +(You can use +'-' +for standard output, +but not on platforms that open standard output in text mode.) +The output file may be a source file because +all files are loaded before the output file is written. +Be careful not to overwrite precious files. +
+-p +load files but do not generate any output file. +Used mainly for syntax checking and for testing precompiled chunks: +corrupted files will probably generate errors when loaded. +Lua always performs a thorough integrity test on precompiled chunks. +Bytecode that passes this test is completely safe, +in the sense that it will not break the interpreter. +However, +there is no guarantee that such code does anything sensible. +(None can be given, because the halting problem is unsolvable.) +If no files are given, then +luac +loads +luac.out +and tests its contents. +No messages are displayed if the file passes the integrity test. +
+-s +strip debug information before writing the output file. +This saves some space in very large chunks, +but if errors occur when running a stripped chunk, +then the error messages may not contain the full information they usually do. +For instance, +line numbers and names of local variables are lost. +
+-v +show version information. +
+luac.out +default output file +
+Lua 5.1 Reference Manual
++ +Copyright © 2006-2008 Lua.org, PUC-Rio. +Freely available under the terms of the +Lua license. + +
+ + + + + + +
+Lua is an extension programming language designed to support +general procedural programming with data description +facilities. +It also offers good support for object-oriented programming, +functional programming, and data-driven programming. +Lua is intended to be used as a powerful, light-weight +scripting language for any program that needs one. +Lua is implemented as a library, written in clean C +(that is, in the common subset of ANSI C and C++). + + +
+Being an extension language, Lua has no notion of a "main" program:
+it only works embedded in a host client,
+called the embedding program or simply the host.
+This host program can invoke functions to execute a piece of Lua code,
+can write and read Lua variables,
+and can register C functions to be called by Lua code.
+Through the use of C functions, Lua can be augmented to cope with
+a wide range of different domains,
+thus creating customized programming languages sharing a syntactical framework.
+The Lua distribution includes a sample host program called lua,
+which uses the Lua library to offer a complete, stand-alone Lua interpreter.
+
+
+
+Lua is free software,
+and is provided as usual with no guarantees,
+as stated in its license.
+The implementation described in this manual is available
+at Lua's official web site, www.lua.org.
+
+
+
+Like any other reference manual, +this document is dry in places. +For a discussion of the decisions behind the design of Lua, +see the technical papers available at Lua's web site. +For a detailed introduction to programming in Lua, +see Roberto's book, Programming in Lua (Second Edition). + + + +
+This section describes the lexis, the syntax, and the semantics of Lua. +In other words, +this section describes +which tokens are valid, +how they can be combined, +and what their combinations mean. + + +
+The language constructs will be explained using the usual extended BNF notation, +in which +{a} means 0 or more a's, and +[a] means an optional a. +Non-terminals are shown like non-terminal, +keywords are shown like kword, +and other terminal symbols are shown like `=´. +The complete syntax of Lua can be found at the end of this manual. + + + +
+Names +(also called identifiers) +in Lua can be any string of letters, +digits, and underscores, +not beginning with a digit. +This coincides with the definition of names in most languages. +(The definition of letter depends on the current locale: +any character considered alphabetic by the current locale +can be used in an identifier.) +Identifiers are used to name variables and table fields. + + +
+The following keywords are reserved +and cannot be used as names: + + +
+ and break do else elseif + end false for function if + in local nil not or + repeat return then true until while ++ +
+Lua is a case-sensitive language:
+and is a reserved word, but And and AND
+are two different, valid names.
+As a convention, names starting with an underscore followed by
+uppercase letters (such as _VERSION)
+are reserved for internal global variables used by Lua.
+
+
+
+The following strings denote other tokens: + +
+ + - * / % ^ #
+ == ~= <= >= < > =
+ ( ) { } [ ]
+ ; : , . .. ...
+
+
+
+Literal strings
+can be delimited by matching single or double quotes,
+and can contain the following C-like escape sequences:
+'\a' (bell),
+'\b' (backspace),
+'\f' (form feed),
+'\n' (newline),
+'\r' (carriage return),
+'\t' (horizontal tab),
+'\v' (vertical tab),
+'\\' (backslash),
+'\"' (quotation mark [double quote]),
+and '\'' (apostrophe [single quote]).
+Moreover, a backslash followed by a real newline
+results in a newline in the string.
+A character in a string may also be specified by its numerical value
+using the escape sequence \ddd,
+where ddd is a sequence of up to three decimal digits.
+(Note that if a numerical escape is to be followed by a digit,
+it must be expressed using exactly three digits.)
+Strings in Lua may contain any 8-bit value, including embedded zeros,
+which can be specified as '\0'.
+
+
+
+To put a double (single) quote, a newline, a backslash, +a carriage return, +or an embedded zero +inside a literal string enclosed by double (single) quotes +you must use an escape sequence. +Any other character may be directly inserted into the literal. +(Some control characters may cause problems for the file system, +but Lua has no problem with them.) + + +
+Literal strings can also be defined using a long format
+enclosed by long brackets.
+We define an opening long bracket of level n as an opening
+square bracket followed by n equal signs followed by another
+opening square bracket.
+So, an opening long bracket of level 0 is written as [[,
+an opening long bracket of level 1 is written as [=[,
+and so on.
+A closing long bracket is defined similarly;
+for instance, a closing long bracket of level 4 is written as ]====].
+A long string starts with an opening long bracket of any level and
+ends at the first closing long bracket of the same level.
+Literals in this bracketed form may run for several lines,
+do not interpret any escape sequences,
+and ignore long brackets of any other level.
+They may contain anything except a closing bracket of the proper level.
+
+
+
+For convenience,
+when the opening long bracket is immediately followed by a newline,
+the newline is not included in the string.
+As an example, in a system using ASCII
+(in which 'a' is coded as 97,
+newline is coded as 10, and '1' is coded as 49),
+the five literals below denote the same string:
+
+
+ a = 'alo\n123"' + a = "alo\n123\"" + a = '\97lo\10\04923"' + a = [[alo + 123"]] + a = [==[ + alo + 123"]==] ++ +
+A numerical constant may be written with an optional decimal part
+and an optional decimal exponent.
+Lua also accepts integer hexadecimal constants,
+by prefixing them with 0x.
+Examples of valid numerical constants are
+
+
+ 3 3.0 3.1416 314.16e-2 0.31416E1 0xff 0x56 ++ +
+A comment starts with a double hyphen (--)
+anywhere outside a string.
+If the text immediately after -- is not an opening long bracket,
+the comment is a short comment,
+which runs until the end of the line.
+Otherwise, it is a long comment,
+which runs until the corresponding closing long bracket.
+Long comments are frequently used to disable code temporarily.
+
+
+
+
+
+
+Lua is a dynamically typed language. +This means that +variables do not have types; only values do. +There are no type definitions in the language. +All values carry their own type. + + +
+All values in Lua are first-class values. +This means that all values can be stored in variables, +passed as arguments to other functions, and returned as results. + + +
+There are eight basic types in Lua:
+nil, boolean, number,
+string, function, userdata,
+thread, and table.
+Nil is the type of the value nil,
+whose main property is to be different from any other value;
+it usually represents the absence of a useful value.
+Boolean is the type of the values false and true.
+Both nil and false make a condition false;
+any other value makes it true.
+Number represents real (double-precision floating-point) numbers.
+(It is easy to build Lua interpreters that use other
+internal representations for numbers,
+such as single-precision float or long integers;
+see file luaconf.h.)
+String represents arrays of characters.
+
+Lua is 8-bit clean:
+strings may contain any 8-bit character,
+including embedded zeros ('\0') (see §2.1).
+
+
+
+Lua can call (and manipulate) functions written in Lua and +functions written in C +(see §2.5.8). + + +
+The type userdata is provided to allow arbitrary C data to +be stored in Lua variables. +This type corresponds to a block of raw memory +and has no pre-defined operations in Lua, +except assignment and identity test. +However, by using metatables, +the programmer can define operations for userdata values +(see §2.8). +Userdata values cannot be created or modified in Lua, +only through the C API. +This guarantees the integrity of data owned by the host program. + + +
+The type thread represents independent threads of execution +and it is used to implement coroutines (see §2.11). +Do not confuse Lua threads with operating-system threads. +Lua supports coroutines on all systems, +even those that do not support threads. + + +
+The type table implements associative arrays,
+that is, arrays that can be indexed not only with numbers,
+but with any value (except nil).
+Tables can be heterogeneous;
+that is, they can contain values of all types (except nil).
+Tables are the sole data structuring mechanism in Lua;
+they may be used to represent ordinary arrays,
+symbol tables, sets, records, graphs, trees, etc.
+To represent records, Lua uses the field name as an index.
+The language supports this representation by
+providing a.name as syntactic sugar for a["name"].
+There are several convenient ways to create tables in Lua
+(see §2.5.7).
+
+
+
+Like indices, +the value of a table field can be of any type (except nil). +In particular, +because functions are first-class values, +table fields may contain functions. +Thus tables may also carry methods (see §2.5.9). + + +
+Tables, functions, threads, and (full) userdata values are objects: +variables do not actually contain these values, +only references to them. +Assignment, parameter passing, and function returns +always manipulate references to such values; +these operations do not imply any kind of copy. + + +
+The library function type returns a string describing the type
+of a given value.
+
+
+
+
+Lua provides automatic conversion between
+string and number values at run time.
+Any arithmetic operation applied to a string tries to convert
+this string to a number, following the usual conversion rules.
+Conversely, whenever a number is used where a string is expected,
+the number is converted to a string, in a reasonable format.
+For complete control over how numbers are converted to strings,
+use the format function from the string library
+(see string.format).
+
+
+
+
+
+
+
+
+Variables are places that store values. + +There are three kinds of variables in Lua: +global variables, local variables, and table fields. + + +
+A single name can denote a global variable or a local variable +(or a function's formal parameter, +which is a particular kind of local variable): + +
+ var ::= Name +
+Name denotes identifiers, as defined in §2.1. + + +
+Any variable is assumed to be global unless explicitly declared +as a local (see §2.4.7). +Local variables are lexically scoped: +local variables can be freely accessed by functions +defined inside their scope (see §2.6). + + +
+Before the first assignment to a variable, its value is nil. + + +
+Square brackets are used to index a table: + +
+ var ::= prefixexp `[´ exp `]´ +
+The meaning of accesses to global variables
+and table fields can be changed via metatables.
+An access to an indexed variable t[i] is equivalent to
+a call gettable_event(t,i).
+(See §2.8 for a complete description of the
+gettable_event function.
+This function is not defined or callable in Lua.
+We use it here only for explanatory purposes.)
+
+
+
+The syntax var.Name is just syntactic sugar for
+var["Name"]:
+
+
+ var ::= prefixexp `.´ Name ++ +
+All global variables live as fields in ordinary Lua tables,
+called environment tables or simply
+environments (see §2.9).
+Each function has its own reference to an environment,
+so that all global variables in this function
+will refer to this environment table.
+When a function is created,
+it inherits the environment from the function that created it.
+To get the environment table of a Lua function,
+you call getfenv.
+To replace it,
+you call setfenv.
+(You can only manipulate the environment of C functions
+through the debug library; (see §5.9).)
+
+
+
+An access to a global variable x
+is equivalent to _env.x,
+which in turn is equivalent to
+
+
+ gettable_event(_env, "x") +
+where _env is the environment of the running function.
+(See §2.8 for a complete description of the
+gettable_event function.
+This function is not defined or callable in Lua.
+Similarly, the _env variable is not defined in Lua.
+We use them here only for explanatory purposes.)
+
+
+
+
+
+
+Lua supports an almost conventional set of statements, +similar to those in Pascal or C. +This set includes +assignment, control structures, function calls, +and variable declarations. + + + +
+The unit of execution of Lua is called a chunk. +A chunk is simply a sequence of statements, +which are executed sequentially. +Each statement can be optionally followed by a semicolon: + +
+ chunk ::= {stat [`;´]}
+
+There are no empty statements and thus ';;' is not legal.
+
+
+
+Lua handles a chunk as the body of an anonymous function +with a variable number of arguments +(see §2.5.9). +As such, chunks can define local variables, +receive arguments, and return values. + + +
+A chunk may be stored in a file or in a string inside the host program. +When a chunk is executed, first it is pre-compiled into instructions for +a virtual machine, +and then the compiled code is executed +by an interpreter for the virtual machine. + + +
+Chunks may also be pre-compiled into binary form;
+see program luac for details.
+Programs in source and compiled forms are interchangeable;
+Lua automatically detects the file type and acts accordingly.
+
+
+
+
+
+
+
+A block is a list of statements; +syntactically, a block is the same as a chunk: + +
+ block ::= chunk ++ +
+A block may be explicitly delimited to produce a single statement: + +
+ stat ::= do block end +
+Explicit blocks are useful +to control the scope of variable declarations. +Explicit blocks are also sometimes used to +add a return or break statement in the middle +of another block (see §2.4.4). + + + + + +
+Lua allows multiple assignment. +Therefore, the syntax for assignment +defines a list of variables on the left side +and a list of expressions on the right side. +The elements in both lists are separated by commas: + +
+ stat ::= varlist `=´ explist
+ varlist ::= var {`,´ var}
+ explist ::= exp {`,´ exp}
++Expressions are discussed in §2.5. + + +
+Before the assignment, +the list of values is adjusted to the length of +the list of variables. +If there are more values than needed, +the excess values are thrown away. +If there are fewer values than needed, +the list is extended with as many nil's as needed. +If the list of expressions ends with a function call, +then all values returned by this call enter in the list of values, +before the adjustment +(except when the call is enclosed in parentheses; see §2.5). + + +
+The assignment statement first evaluates all its expressions +and only then are the assignments performed. +Thus the code + +
+ i = 3 + i, a[i] = i+1, 20 +
+sets a[3] to 20, without affecting a[4]
+because the i in a[i] is evaluated (to 3)
+before it is assigned 4.
+Similarly, the line
+
+
+ x, y = y, x +
+exchanges the values of x and y.
+
+
+
+The meaning of assignments to global variables
+and table fields can be changed via metatables.
+An assignment to an indexed variable t[i] = val is equivalent to
+settable_event(t,i,val).
+(See §2.8 for a complete description of the
+settable_event function.
+This function is not defined or callable in Lua.
+We use it here only for explanatory purposes.)
+
+
+
+An assignment to a global variable x = val
+is equivalent to the assignment
+_env.x = val,
+which in turn is equivalent to
+
+
+ settable_event(_env, "x", val) +
+where _env is the environment of the running function.
+(The _env variable is not defined in Lua.
+We use it here only for explanatory purposes.)
+
+
+
+
+
+
+The control structures +if, while, and repeat have the usual meaning and +familiar syntax: + + + + +
+ stat ::= while exp do block end
+ stat ::= repeat block until exp
+ stat ::= if exp then block {elseif exp then block} [else block] end
++Lua also has a for statement, in two flavors (see §2.4.5). + + +
+The condition expression of a +control structure may return any value. +Both false and nil are considered false. +All values different from nil and false are considered true +(in particular, the number 0 and the empty string are also true). + + +
+In the repeat–until loop, +the inner block does not end at the until keyword, +but only after the condition. +So, the condition can refer to local variables +declared inside the loop block. + + +
+The return statement is used to return values +from a function or a chunk (which is just a function). + +Functions and chunks may return more than one value, +so the syntax for the return statement is + +
+ stat ::= return [explist] ++ +
+The break statement is used to terminate the execution of a +while, repeat, or for loop, +skipping to the next statement after the loop: + + +
+ stat ::= break +
+A break ends the innermost enclosing loop. + + +
+The return and break
+statements can only be written as the last statement of a block.
+If it is really necessary to return or break in the
+middle of a block,
+then an explicit inner block can be used,
+as in the idioms
+do return end and do break end,
+because now return and break are the last statements in
+their (inner) blocks.
+
+
+
+
+
+
+ +The for statement has two forms: +one numeric and one generic. + + +
+The numeric for loop repeats a block of code while a +control variable runs through an arithmetic progression. +It has the following syntax: + +
+ stat ::= for Name `=´ exp `,´ exp [`,´ exp] do block end +
+The block is repeated for name starting at the value of +the first exp, until it passes the second exp by steps of the +third exp. +More precisely, a for statement like + +
+ for v = e1, e2, e3 do block end +
+is equivalent to the code: + +
+ do + local var, limit, step = tonumber(e1), tonumber(e2), tonumber(e3) + if not (var and limit and step) then error() end + while (step > 0 and var <= limit) or (step <= 0 and var >= limit) do + local v = var + block + var = var + step + end + end +
+Note the following: + +
var, limit, and step are invisible variables.
+The names are here for explanatory purposes only.
+v is local to the loop;
+you cannot use its value after the for ends or is broken.
+If you need this value,
+assign it to another variable before breaking or exiting the loop.
++The generic for statement works over functions, +called iterators. +On each iteration, the iterator function is called to produce a new value, +stopping when this new value is nil. +The generic for loop has the following syntax: + +
+ stat ::= for namelist in explist do block end
+ namelist ::= Name {`,´ Name}
++A for statement like + +
+ for var_1, ···, var_n in explist do block end +
+is equivalent to the code: + +
+ do + local f, s, var = explist + while true do + local var_1, ···, var_n = f(s, var) + var = var_1 + if var == nil then break end + block + end + end +
+Note the following: + +
explist is evaluated only once.
+Its results are an iterator function,
+a state,
+and an initial value for the first iterator variable.
+f, s, and var are invisible variables.
+The names are here for explanatory purposes only.
+var_i are local to the loop;
+you cannot use their values after the for ends.
+If you need these values,
+then assign them to other variables before breaking or exiting the loop.
++To allow possible side-effects, +function calls can be executed as statements: + +
+ stat ::= functioncall +
+In this case, all returned values are thrown away. +Function calls are explained in §2.5.8. + + + + + +
+Local variables may be declared anywhere inside a block. +The declaration may include an initial assignment: + +
+ stat ::= local namelist [`=´ explist] +
+If present, an initial assignment has the same semantics +of a multiple assignment (see §2.4.3). +Otherwise, all variables are initialized with nil. + + +
+A chunk is also a block (see §2.4.1), +and so local variables can be declared in a chunk outside any explicit block. +The scope of such local variables extends until the end of the chunk. + + +
+The visibility rules for local variables are explained in §2.6. + + + + + + + +
+The basic expressions in Lua are the following: + +
+ exp ::= prefixexp + exp ::= nil | false | true + exp ::= Number + exp ::= String + exp ::= function + exp ::= tableconstructor + exp ::= `...´ + exp ::= exp binop exp + exp ::= unop exp + prefixexp ::= var | functioncall | `(´ exp `)´ ++ +
+Numbers and literal strings are explained in §2.1;
+variables are explained in §2.3;
+function definitions are explained in §2.5.9;
+function calls are explained in §2.5.8;
+table constructors are explained in §2.5.7.
+Vararg expressions,
+denoted by three dots ('...'), can only be used when
+directly inside a vararg function;
+they are explained in §2.5.9.
+
+
+
+Binary operators comprise arithmetic operators (see §2.5.1), +relational operators (see §2.5.2), logical operators (see §2.5.3), +and the concatenation operator (see §2.5.4). +Unary operators comprise the unary minus (see §2.5.1), +the unary not (see §2.5.3), +and the unary length operator (see §2.5.5). + + +
+Both function calls and vararg expressions may result in multiple values. +If the expression is used as a statement (see §2.4.6) +(only possible for function calls), +then its return list is adjusted to zero elements, +thus discarding all returned values. +If the expression is used as the last (or the only) element +of a list of expressions, +then no adjustment is made +(unless the call is enclosed in parentheses). +In all other contexts, +Lua adjusts the result list to one element, +discarding all values except the first one. + + +
+Here are some examples: + +
+ f() -- adjusted to 0 results
+ g(f(), x) -- f() is adjusted to 1 result
+ g(x, f()) -- g gets x plus all results from f()
+ a,b,c = f(), x -- f() is adjusted to 1 result (c gets nil)
+ a,b = ... -- a gets the first vararg parameter, b gets
+ -- the second (both a and b may get nil if there
+ -- is no corresponding vararg parameter)
+
+ a,b,c = x, f() -- f() is adjusted to 2 results
+ a,b,c = f() -- f() is adjusted to 3 results
+ return f() -- returns all results from f()
+ return ... -- returns all received vararg parameters
+ return x,y,f() -- returns x, y, and all results from f()
+ {f()} -- creates a list with all results from f()
+ {...} -- creates a list with all vararg parameters
+ {f(), nil} -- f() is adjusted to 1 result
+
+
+
+An expression enclosed in parentheses always results in only one value.
+Thus,
+(f(x,y,z)) is always a single value,
+even if f returns several values.
+(The value of (f(x,y,z)) is the first value returned by f
+or nil if f does not return any values.)
+
+
+
+
+Lua supports the usual arithmetic operators:
+the binary + (addition),
+- (subtraction), * (multiplication),
+/ (division), % (modulo), and ^ (exponentiation);
+and unary - (negation).
+If the operands are numbers, or strings that can be converted to
+numbers (see §2.2.1),
+then all operations have the usual meaning.
+Exponentiation works for any exponent.
+For instance, x^(-0.5) computes the inverse of the square root of x.
+Modulo is defined as
+
+
+ a % b == a - math.floor(a/b)*b +
+That is, it is the remainder of a division that rounds +the quotient towards minus infinity. + + + + + +
+The relational operators in Lua are + +
+ == ~= < > <= >= +
+These operators always result in false or true. + + +
+Equality (==) first compares the type of its operands.
+If the types are different, then the result is false.
+Otherwise, the values of the operands are compared.
+Numbers and strings are compared in the usual way.
+Objects (tables, userdata, threads, and functions)
+are compared by reference:
+two objects are considered equal only if they are the same object.
+Every time you create a new object
+(a table, userdata, thread, or function),
+this new object is different from any previously existing object.
+
+
+
+You can change the way that Lua compares tables and userdata +by using the "eq" metamethod (see §2.8). + + +
+The conversion rules of §2.2.1
+do not apply to equality comparisons.
+Thus, "0"==0 evaluates to false,
+and t[0] and t["0"] denote different
+entries in a table.
+
+
+
+The operator ~= is exactly the negation of equality (==).
+
+
+
+The order operators work as follows. +If both arguments are numbers, then they are compared as such. +Otherwise, if both arguments are strings, +then their values are compared according to the current locale. +Otherwise, Lua tries to call the "lt" or the "le" +metamethod (see §2.8). + + + + + +
+The logical operators in Lua are +and, or, and not. +Like the control structures (see §2.4.4), +all logical operators consider both false and nil as false +and anything else as true. + + +
+The negation operator not always returns false or true. +The conjunction operator and returns its first argument +if this value is false or nil; +otherwise, and returns its second argument. +The disjunction operator or returns its first argument +if this value is different from nil and false; +otherwise, or returns its second argument. +Both and and or use short-cut evaluation; +that is, +the second operand is evaluated only if necessary. +Here are some examples: + +
+ 10 or 20 --> 10 + 10 or error() --> 10 + nil or "a" --> "a" + nil and 10 --> nil + false and error() --> false + false and nil --> false + false or nil --> nil + 10 and 20 --> 20 +
+(In this manual, +--> indicates the result of the preceding expression.) + + + + + +
+The string concatenation operator in Lua is
+denoted by two dots ('..').
+If both operands are strings or numbers, then they are converted to
+strings according to the rules mentioned in §2.2.1.
+Otherwise, the "concat" metamethod is called (see §2.8).
+
+
+
+
+
+
+The length operator is denoted by the unary operator #.
+The length of a string is its number of bytes
+(that is, the usual meaning of string length when each
+character is one byte).
+
+
+
+The length of a table t is defined to be any
+integer index n
+such that t[n] is not nil and t[n+1] is nil;
+moreover, if t[1] is nil, n may be zero.
+For a regular array, with non-nil values from 1 to a given n,
+its length is exactly that n,
+the index of its last value.
+If the array has "holes"
+(that is, nil values between other non-nil values),
+then #t may be any of the indices that
+directly precedes a nil value
+(that is, it may consider any such nil value as the end of
+the array).
+
+
+
+
+
+
+Operator precedence in Lua follows the table below, +from lower to higher priority: + +
+ or + and + < > <= >= ~= == + .. + + - + * / % + not # - (unary) + ^ +
+As usual,
+you can use parentheses to change the precedences of an expression.
+The concatenation ('..') and exponentiation ('^')
+operators are right associative.
+All other binary operators are left associative.
+
+
+
+
+
+
+Table constructors are expressions that create tables. +Every time a constructor is evaluated, a new table is created. +Constructors can be used to create empty tables, +or to create a table and initialize some of its fields. +The general syntax for constructors is + +
+ tableconstructor ::= `{´ [fieldlist] `}´
+ fieldlist ::= field {fieldsep field} [fieldsep]
+ field ::= `[´ exp `]´ `=´ exp | Name `=´ exp | exp
+ fieldsep ::= `,´ | `;´
+
+
+
+Each field of the form [exp1] = exp2 adds to the new table an entry
+with key exp1 and value exp2.
+A field of the form name = exp is equivalent to
+["name"] = exp.
+Finally, fields of the form exp are equivalent to
+[i] = exp, where i are consecutive numerical integers,
+starting with 1.
+Fields in the other formats do not affect this counting.
+For example,
+
+
+ a = { [f(1)] = g; "x", "y"; x = 1, f(x), [30] = 23; 45 }
++is equivalent to + +
+ do
+ local t = {}
+ t[f(1)] = g
+ t[1] = "x" -- 1st exp
+ t[2] = "y" -- 2nd exp
+ t.x = 1 -- t["x"] = 1
+ t[3] = f(x) -- 3rd exp
+ t[30] = 23
+ t[4] = 45 -- 4th exp
+ a = t
+ end
+
+
+
+If the last field in the list has the form exp
+and the expression is a function call or a vararg expression,
+then all values returned by this expression enter the list consecutively
+(see §2.5.8).
+To avoid this,
+enclose the function call (or the vararg expression)
+in parentheses (see §2.5).
+
+
+
+The field list may have an optional trailing separator, +as a convenience for machine-generated code. + + + + + +
+A function call in Lua has the following syntax: + +
+ functioncall ::= prefixexp args +
+In a function call, +first prefixexp and args are evaluated. +If the value of prefixexp has type function, +then this function is called +with the given arguments. +Otherwise, the prefixexp "call" metamethod is called, +having as first parameter the value of prefixexp, +followed by the original call arguments +(see §2.8). + + +
+The form + +
+ functioncall ::= prefixexp `:´ Name args +
+can be used to call "methods".
+A call v:name(args)
+is syntactic sugar for v.name(v,args),
+except that v is evaluated only once.
+
+
+
+Arguments have the following syntax: + +
+ args ::= `(´ [explist] `)´ + args ::= tableconstructor + args ::= String +
+All argument expressions are evaluated before the call.
+A call of the form f{fields} is
+syntactic sugar for f({fields});
+that is, the argument list is a single new table.
+A call of the form f'string'
+(or f"string" or f[[string]])
+is syntactic sugar for f('string');
+that is, the argument list is a single literal string.
+
+
+
+As an exception to the free-format syntax of Lua,
+you cannot put a line break before the '(' in a function call.
+This restriction avoids some ambiguities in the language.
+If you write
+
+
+ a = f + (g).x(a) +
+Lua would see that as a single statement, a = f(g).x(a).
+So, if you want two statements, you must add a semi-colon between them.
+If you actually want to call f,
+you must remove the line break before (g).
+
+
+
+A call of the form return functioncall is called
+a tail call.
+Lua implements proper tail calls
+(or proper tail recursion):
+in a tail call,
+the called function reuses the stack entry of the calling function.
+Therefore, there is no limit on the number of nested tail calls that
+a program can execute.
+However, a tail call erases any debug information about the
+calling function.
+Note that a tail call only happens with a particular syntax,
+where the return has one single function call as argument;
+this syntax makes the calling function return exactly
+the returns of the called function.
+So, none of the following examples are tail calls:
+
+
+ return (f(x)) -- results adjusted to 1 + return 2 * f(x) + return x, f(x) -- additional results + f(x); return -- results discarded + return x or f(x) -- results adjusted to 1 ++ + + + +
+The syntax for function definition is + +
+ function ::= function funcbody + funcbody ::= `(´ [parlist] `)´ block end ++ +
+The following syntactic sugar simplifies function definitions: + +
+ stat ::= function funcname funcbody
+ stat ::= local function Name funcbody
+ funcname ::= Name {`.´ Name} [`:´ Name]
++The statement + +
+ function f () body end +
+translates to + +
+ f = function () body end +
+The statement + +
+ function t.a.b.c.f () body end +
+translates to + +
+ t.a.b.c.f = function () body end +
+The statement + +
+ local function f () body end +
+translates to + +
+ local f; f = function () body end +
+not to + +
+ local f = function () body end +
+(This only makes a difference when the body of the function
+contains references to f.)
+
+
+
+A function definition is an executable expression, +whose value has type function. +When Lua pre-compiles a chunk, +all its function bodies are pre-compiled too. +Then, whenever Lua executes the function definition, +the function is instantiated (or closed). +This function instance (or closure) +is the final value of the expression. +Different instances of the same function +may refer to different external local variables +and may have different environment tables. + + +
+Parameters act as local variables that are +initialized with the argument values: + +
+ parlist ::= namelist [`,´ `...´] | `...´ +
+When a function is called,
+the list of arguments is adjusted to
+the length of the list of parameters,
+unless the function is a variadic or vararg function,
+which is
+indicated by three dots ('...') at the end of its parameter list.
+A vararg function does not adjust its argument list;
+instead, it collects all extra arguments and supplies them
+to the function through a vararg expression,
+which is also written as three dots.
+The value of this expression is a list of all actual extra arguments,
+similar to a function with multiple results.
+If a vararg expression is used inside another expression
+or in the middle of a list of expressions,
+then its return list is adjusted to one element.
+If the expression is used as the last element of a list of expressions,
+then no adjustment is made
+(unless the call is enclosed in parentheses).
+
+
+
+As an example, consider the following definitions: + +
+ function f(a, b) end + function g(a, b, ...) end + function r() return 1,2,3 end +
+Then, we have the following mapping from arguments to parameters and +to the vararg expression: + +
+ CALL PARAMETERS + + f(3) a=3, b=nil + f(3, 4) a=3, b=4 + f(3, 4, 5) a=3, b=4 + f(r(), 10) a=1, b=10 + f(r()) a=1, b=2 + + g(3) a=3, b=nil, ... --> (nothing) + g(3, 4) a=3, b=4, ... --> (nothing) + g(3, 4, 5, 8) a=3, b=4, ... --> 5 8 + g(5, r()) a=5, b=1, ... --> 2 3 ++ +
+Results are returned using the return statement (see §2.4.4). +If control reaches the end of a function +without encountering a return statement, +then the function returns with no results. + + +
+The colon syntax
+is used for defining methods,
+that is, functions that have an implicit extra parameter self.
+Thus, the statement
+
+
+ function t.a.b.c:f (params) body end +
+is syntactic sugar for + +
+ t.a.b.c.f = function (self, params) body end ++ + + + + + +
+ +Lua is a lexically scoped language. +The scope of variables begins at the first statement after +their declaration and lasts until the end of the innermost block that +includes the declaration. +Consider the following example: + +
+ x = 10 -- global variable + do -- new block + local x = x -- new 'x', with value 10 + print(x) --> 10 + x = x+1 + do -- another block + local x = x+1 -- another 'x' + print(x) --> 12 + end + print(x) --> 11 + end + print(x) --> 10 (the global one) ++ +
+Notice that, in a declaration like local x = x,
+the new x being declared is not in scope yet,
+and so the second x refers to the outside variable.
+
+
+
+Because of the lexical scoping rules, +local variables can be freely accessed by functions +defined inside their scope. +A local variable used by an inner function is called +an upvalue, or external local variable, +inside the inner function. + + +
+Notice that each execution of a local statement +defines new local variables. +Consider the following example: + +
+ a = {}
+ local x = 20
+ for i=1,10 do
+ local y = 0
+ a[i] = function () y=y+1; return x+y end
+ end
+
+The loop creates ten closures
+(that is, ten instances of the anonymous function).
+Each of these closures uses a different y variable,
+while all of them share the same x.
+
+
+
+
+
+
+Because Lua is an embedded extension language,
+all Lua actions start from C code in the host program
+calling a function from the Lua library (see lua_pcall).
+Whenever an error occurs during Lua compilation or execution,
+control returns to C,
+which can take appropriate measures
+(such as printing an error message).
+
+
+
+Lua code can explicitly generate an error by calling the
+error function.
+If you need to catch errors in Lua,
+you can use the pcall function.
+
+
+
+
+
+
+Every value in Lua may have a metatable.
+This metatable is an ordinary Lua table
+that defines the behavior of the original value
+under certain special operations.
+You can change several aspects of the behavior
+of operations over a value by setting specific fields in its metatable.
+For instance, when a non-numeric value is the operand of an addition,
+Lua checks for a function in the field "__add" in its metatable.
+If it finds one,
+Lua calls this function to perform the addition.
+
+
+
+We call the keys in a metatable events
+and the values metamethods.
+In the previous example, the event is "add"
+and the metamethod is the function that performs the addition.
+
+
+
+You can query the metatable of any value
+through the getmetatable function.
+
+
+
+You can replace the metatable of tables
+through the setmetatable
+function.
+You cannot change the metatable of other types from Lua
+(except using the debug library);
+you must use the C API for that.
+
+
+
+Tables and full userdata have individual metatables +(although multiple tables and userdata can share their metatables); +values of all other types share one single metatable per type. +So, there is one single metatable for all numbers, +one for all strings, etc. + + +
+A metatable may control how an object behaves in arithmetic operations, +order comparisons, concatenation, length operation, and indexing. +A metatable can also define a function to be called when a userdata +is garbage collected. +For each of these operations Lua associates a specific key +called an event. +When Lua performs one of these operations over a value, +it checks whether this value has a metatable with the corresponding event. +If so, the value associated with that key (the metamethod) +controls how Lua will perform the operation. + + +
+Metatables control the operations listed next.
+Each operation is identified by its corresponding name.
+The key for each operation is a string with its name prefixed by
+two underscores, '__';
+for instance, the key for operation "add" is the
+string "__add".
+The semantics of these operations is better explained by a Lua function
+describing how the interpreter executes the operation.
+
+
+
+The code shown here in Lua is only illustrative;
+the real behavior is hard coded in the interpreter
+and it is much more efficient than this simulation.
+All functions used in these descriptions
+(rawget, tonumber, etc.)
+are described in §5.1.
+In particular, to retrieve the metamethod of a given object,
+we use the expression
+
+
+ metatable(obj)[event] +
+This should be read as + +
+ rawget(getmetatable(obj) or {}, event)
++ +That is, the access to a metamethod does not invoke other metamethods, +and the access to objects with no metatables does not fail +(it simply results in nil). + + + +
+ operation.
+
+
+
+
+The function getbinhandler below defines how Lua chooses a handler
+for a binary operation.
+First, Lua tries the first operand.
+If its type does not define a handler for the operation,
+then Lua tries the second operand.
+
+
+ function getbinhandler (op1, op2, event) + return metatable(op1)[event] or metatable(op2)[event] + end +
+By using this function,
+the behavior of the op1 + op2 is
+
+
+ function add_event (op1, op2) + local o1, o2 = tonumber(op1), tonumber(op2) + if o1 and o2 then -- both operands are numeric? + return o1 + o2 -- '+' here is the primitive 'add' + else -- at least one of the operands is not numeric + local h = getbinhandler(op1, op2, "__add") + if h then + -- call the handler with both operands + return (h(op1, op2)) + else -- no handler available: default behavior + error(···) + end + end + end +
+
- operation.
+
+Behavior similar to the "add" operation.
+* operation.
+
+Behavior similar to the "add" operation.
+/ operation.
+
+Behavior similar to the "add" operation.
+% operation.
+
+Behavior similar to the "add" operation,
+with the operation
+o1 - floor(o1/o2)*o2 as the primitive operation.
+^ (exponentiation) operation.
+
+Behavior similar to the "add" operation,
+with the function pow (from the C math library)
+as the primitive operation.
+- operation.
+
+
++ function unm_event (op) + local o = tonumber(op) + if o then -- operand is numeric? + return -o -- '-' here is the primitive 'unm' + else -- the operand is not numeric. + -- Try to get a handler from the operand + local h = metatable(op).__unm + if h then + -- call the handler with the operand + return (h(op)) + else -- no handler available: default behavior + error(···) + end + end + end +
+
.. (concatenation) operation.
+
+
++ function concat_event (op1, op2) + if (type(op1) == "string" or type(op1) == "number") and + (type(op2) == "string" or type(op2) == "number") then + return op1 .. op2 -- primitive string concatenation + else + local h = getbinhandler(op1, op2, "__concat") + if h then + return (h(op1, op2)) + else + error(···) + end + end + end +
+
# operation.
+
+
++ function len_event (op) + if type(op) == "string" then + return strlen(op) -- primitive string length + elseif type(op) == "table" then + return #op -- primitive table length + else + local h = metatable(op).__len + if h then + -- call the handler with the operand + return (h(op)) + else -- no handler available: default behavior + error(···) + end + end + end +
+See §2.5.5 for a description of the length of a table. +
== operation.
+
+The function getcomphandler defines how Lua chooses a metamethod
+for comparison operators.
+A metamethod only is selected when both objects
+being compared have the same type
+and the same metamethod for the selected operation.
+
++ function getcomphandler (op1, op2, event) + if type(op1) ~= type(op2) then return nil end + local mm1 = metatable(op1)[event] + local mm2 = metatable(op2)[event] + if mm1 == mm2 then return mm1 else return nil end + end +
+The "eq" event is defined as follows: + +
+ function eq_event (op1, op2) + if type(op1) ~= type(op2) then -- different types? + return false -- different objects + end + if op1 == op2 then -- primitive equal? + return true -- objects are equal + end + -- try metamethod + local h = getcomphandler(op1, op2, "__eq") + if h then + return (h(op1, op2)) + else + return false + end + end +
+a ~= b is equivalent to not (a == b).
+
< operation.
+
+
++ function lt_event (op1, op2) + if type(op1) == "number" and type(op2) == "number" then + return op1 < op2 -- numeric comparison + elseif type(op1) == "string" and type(op2) == "string" then + return op1 < op2 -- lexicographic comparison + else + local h = getcomphandler(op1, op2, "__lt") + if h then + return (h(op1, op2)) + else + error(···); + end + end + end +
+a > b is equivalent to b < a.
+
<= operation.
+
+
++ function le_event (op1, op2) + if type(op1) == "number" and type(op2) == "number" then + return op1 <= op2 -- numeric comparison + elseif type(op1) == "string" and type(op2) == "string" then + return op1 <= op2 -- lexicographic comparison + else + local h = getcomphandler(op1, op2, "__le") + if h then + return (h(op1, op2)) + else + h = getcomphandler(op1, op2, "__lt") + if h then + return not h(op2, op1) + else + error(···); + end + end + end + end +
+a >= b is equivalent to b <= a.
+Note that, in the absence of a "le" metamethod,
+Lua tries the "lt", assuming that a <= b is
+equivalent to not (b < a).
+
table[key].
+
+
++ function gettable_event (table, key) + local h + if type(table) == "table" then + local v = rawget(table, key) + if v ~= nil then return v end + h = metatable(table).__index + if h == nil then return nil end + else + h = metatable(table).__index + if h == nil then + error(···); + end + end + if type(h) == "function" then + return (h(table, key)) -- call the handler + else return h[key] -- or repeat operation on it + end + end +
+
table[key] = value.
+
+
++ function settable_event (table, key, value) + local h + if type(table) == "table" then + local v = rawget(table, key) + if v ~= nil then rawset(table, key, value); return end + h = metatable(table).__newindex + if h == nil then rawset(table, key, value); return end + else + h = metatable(table).__newindex + if h == nil then + error(···); + end + end + if type(h) == "function" then + h(table, key,value) -- call the handler + else h[key] = value -- or repeat operation on it + end + end +
+
+ function function_event (func, ...) + if type(func) == "function" then + return func(...) -- primitive call + else + local h = metatable(func).__call + if h then + return h(func, ...) + else + error(···) + end + end + end +
+
+Besides metatables, +objects of types thread, function, and userdata +have another table associated with them, +called their environment. +Like metatables, environments are regular tables and +multiple objects can share the same environment. + + +
+Environments associated with userdata have no meaning for Lua. +It is only a convenience feature for programmers to associate a table to +a userdata. + + +
+Environments associated with threads are called
+global environments.
+They are used as the default environment for their threads and
+non-nested functions created by the thread
+(through loadfile, loadstring or load)
+and can be directly accessed by C code (see §3.3).
+
+
+
+Environments associated with C functions can be directly +accessed by C code (see §3.3). +They are used as the default environment for other C functions +created by the function. + + +
+Environments associated with Lua functions are used to resolve +all accesses to global variables within the function (see §2.3). +They are used as the default environment for other Lua functions +created by the function. + + +
+You can change the environment of a Lua function or the
+running thread by calling setfenv.
+You can get the environment of a Lua function or the running thread
+by calling getfenv.
+To manipulate the environment of other objects
+(userdata, C functions, other threads) you must
+use the C API.
+
+
+
+
+
+
+Lua performs automatic memory management. +This means that +you have to worry neither about allocating memory for new objects +nor about freeing it when the objects are no longer needed. +Lua manages memory automatically by running +a garbage collector from time to time +to collect all dead objects +(that is, these objects that are no longer accessible from Lua). +All objects in Lua are subject to automatic management: +tables, userdata, functions, threads, and strings. + + +
+Lua implements an incremental mark-and-sweep collector. +It uses two numbers to control its garbage-collection cycles: +the garbage-collector pause and +the garbage-collector step multiplier. + + +
+The garbage-collector pause +controls how long the collector waits before starting a new cycle. +Larger values make the collector less aggressive. +Values smaller than 1 mean the collector will not wait to +start a new cycle. +A value of 2 means that the collector waits for the total memory in use +to double before starting a new cycle. + + +
+The step multiplier +controls the relative speed of the collector relative to +memory allocation. +Larger values make the collector more aggressive but also increase +the size of each incremental step. +Values smaller than 1 make the collector too slow and +may result in the collector never finishing a cycle. +The default, 2, means that the collector runs at "twice" +the speed of memory allocation. + + +
+You can change these numbers by calling lua_gc in C
+or collectgarbage in Lua.
+Both get percentage points as arguments
+(so an argument of 100 means a real value of 1).
+With these functions you can also control
+the collector directly (e.g., stop and restart it).
+
+
+
+
+Using the C API, +you can set garbage-collector metamethods for userdata (see §2.8). +These metamethods are also called finalizers. +Finalizers allow you to coordinate Lua's garbage collection +with external resource management +(such as closing files, network or database connections, +or freeing your own memory). + + +
+Garbage userdata with a field __gc in their metatables are not
+collected immediately by the garbage collector.
+Instead, Lua puts them in a list.
+After the collection,
+Lua does the equivalent of the following function
+for each userdata in that list:
+
+
+ function gc_event (udata) + local h = metatable(udata).__gc + if h then + h(udata) + end + end ++ +
+At the end of each garbage-collection cycle, +the finalizers for userdata are called in reverse +order of their creation, +among those collected in that cycle. +That is, the first finalizer to be called is the one associated +with the userdata created last in the program. +The userdata itself is freed only in the next garbage-collection cycle. + + + + + +
+A weak table is a table whose elements are +weak references. +A weak reference is ignored by the garbage collector. +In other words, +if the only references to an object are weak references, +then the garbage collector will collect this object. + + +
+A weak table can have weak keys, weak values, or both.
+A table with weak keys allows the collection of its keys,
+but prevents the collection of its values.
+A table with both weak keys and weak values allows the collection of
+both keys and values.
+In any case, if either the key or the value is collected,
+the whole pair is removed from the table.
+The weakness of a table is controlled by the
+__mode field of its metatable.
+If the __mode field is a string containing the character 'k',
+the keys in the table are weak.
+If __mode contains 'v',
+the values in the table are weak.
+
+
+
+After you use a table as a metatable,
+you should not change the value of its field __mode.
+Otherwise, the weak behavior of the tables controlled by this
+metatable is undefined.
+
+
+
+
+
+
+
+
+Lua supports coroutines, +also called collaborative multithreading. +A coroutine in Lua represents an independent thread of execution. +Unlike threads in multithread systems, however, +a coroutine only suspends its execution by explicitly calling +a yield function. + + +
+You create a coroutine with a call to coroutine.create.
+Its sole argument is a function
+that is the main function of the coroutine.
+The create function only creates a new coroutine and
+returns a handle to it (an object of type thread);
+it does not start the coroutine execution.
+
+
+
+When you first call coroutine.resume,
+passing as its first argument
+the thread returned by coroutine.create,
+the coroutine starts its execution,
+at the first line of its main function.
+Extra arguments passed to coroutine.resume are passed on
+to the coroutine main function.
+After the coroutine starts running,
+it runs until it terminates or yields.
+
+
+
+A coroutine can terminate its execution in two ways:
+normally, when its main function returns
+(explicitly or implicitly, after the last instruction);
+and abnormally, if there is an unprotected error.
+In the first case, coroutine.resume returns true,
+plus any values returned by the coroutine main function.
+In case of errors, coroutine.resume returns false
+plus an error message.
+
+
+
+A coroutine yields by calling coroutine.yield.
+When a coroutine yields,
+the corresponding coroutine.resume returns immediately,
+even if the yield happens inside nested function calls
+(that is, not in the main function,
+but in a function directly or indirectly called by the main function).
+In the case of a yield, coroutine.resume also returns true,
+plus any values passed to coroutine.yield.
+The next time you resume the same coroutine,
+it continues its execution from the point where it yielded,
+with the call to coroutine.yield returning any extra
+arguments passed to coroutine.resume.
+
+
+
+Like coroutine.create,
+the coroutine.wrap function also creates a coroutine,
+but instead of returning the coroutine itself,
+it returns a function that, when called, resumes the coroutine.
+Any arguments passed to this function
+go as extra arguments to coroutine.resume.
+coroutine.wrap returns all the values returned by coroutine.resume,
+except the first one (the boolean error code).
+Unlike coroutine.resume,
+coroutine.wrap does not catch errors;
+any error is propagated to the caller.
+
+
+
+As an example, +consider the following code: + +
+ function foo (a)
+ print("foo", a)
+ return coroutine.yield(2*a)
+ end
+
+ co = coroutine.create(function (a,b)
+ print("co-body", a, b)
+ local r = foo(a+1)
+ print("co-body", r)
+ local r, s = coroutine.yield(a+b, a-b)
+ print("co-body", r, s)
+ return b, "end"
+ end)
+
+ print("main", coroutine.resume(co, 1, 10))
+ print("main", coroutine.resume(co, "r"))
+ print("main", coroutine.resume(co, "x", "y"))
+ print("main", coroutine.resume(co, "x", "y"))
++When you run it, it produces the following output: + +
+ co-body 1 10 + foo 2 + + main true 4 + co-body r + main true 11 -9 + co-body x y + main true 10 end + main false cannot resume dead coroutine ++ + + + +
+
+This section describes the C API for Lua, that is,
+the set of C functions available to the host program to communicate
+with Lua.
+All API functions and related types and constants
+are declared in the header file lua.h.
+
+
+
+Even when we use the term "function", +any facility in the API may be provided as a macro instead. +All such macros use each of their arguments exactly once +(except for the first argument, which is always a Lua state), +and so do not generate any hidden side-effects. + + +
+As in most C libraries,
+the Lua API functions do not check their arguments for validity or consistency.
+However, you can change this behavior by compiling Lua
+with a proper definition for the macro luai_apicheck,
+in file luaconf.h.
+
+
+
+
+Lua uses a virtual stack to pass values to and from C. +Each element in this stack represents a Lua value +(nil, number, string, etc.). + + +
+Whenever Lua calls C, the called function gets a new stack,
+which is independent of previous stacks and of stacks of
+C functions that are still active.
+This stack initially contains any arguments to the C function
+and it is where the C function pushes its results
+to be returned to the caller (see lua_CFunction).
+
+
+
+For convenience,
+most query operations in the API do not follow a strict stack discipline.
+Instead, they can refer to any element in the stack
+by using an index:
+A positive index represents an absolute stack position
+(starting at 1);
+a negative index represents an offset relative to the top of the stack.
+More specifically, if the stack has n elements,
+then index 1 represents the first element
+(that is, the element that was pushed onto the stack first)
+and
+index n represents the last element;
+index -1 also represents the last element
+(that is, the element at the top)
+and index -n represents the first element.
+We say that an index is valid
+if it lies between 1 and the stack top
+(that is, if 1 ≤ abs(index) ≤ top).
+
+
+
+
+
+
+
+When you interact with Lua API,
+you are responsible for ensuring consistency.
+In particular,
+you are responsible for controlling stack overflow.
+You can use the function lua_checkstack
+to grow the stack size.
+
+
+
+Whenever Lua calls C,
+it ensures that at least LUA_MINSTACK stack positions are available.
+LUA_MINSTACK is defined as 20,
+so that usually you do not have to worry about stack space
+unless your code has loops pushing elements onto the stack.
+
+
+
+Most query functions accept as indices any value inside the
+available stack space, that is, indices up to the maximum stack size
+you have set through lua_checkstack.
+Such indices are called acceptable indices.
+More formally, we define an acceptable index
+as follows:
+
+
+ (index < 0 && abs(index) <= top) || + (index > 0 && index <= stackspace) +
+Note that 0 is never an acceptable index. + + + + + +
+Unless otherwise noted, +any function that accepts valid indices can also be called with +pseudo-indices, +which represent some Lua values that are accessible to C code +but which are not in the stack. +Pseudo-indices are used to access the thread environment, +the function environment, +the registry, +and the upvalues of a C function (see §3.4). + + +
+The thread environment (where global variables live) is
+always at pseudo-index LUA_GLOBALSINDEX.
+The environment of the running C function is always
+at pseudo-index LUA_ENVIRONINDEX.
+
+
+
+To access and change the value of global variables, +you can use regular table operations over an environment table. +For instance, to access the value of a global variable, do + +
+ lua_getfield(L, LUA_GLOBALSINDEX, varname); ++ + + + +
+When a C function is created,
+it is possible to associate some values with it,
+thus creating a C closure;
+these values are called upvalues and are
+accessible to the function whenever it is called
+(see lua_pushcclosure).
+
+
+
+Whenever a C function is called,
+its upvalues are located at specific pseudo-indices.
+These pseudo-indices are produced by the macro
+lua_upvalueindex.
+The first value associated with a function is at position
+lua_upvalueindex(1), and so on.
+Any access to lua_upvalueindex(n),
+where n is greater than the number of upvalues of the
+current function,
+produces an acceptable (but invalid) index.
+
+
+
+
+
+
+Lua provides a registry,
+a pre-defined table that can be used by any C code to
+store whatever Lua value it needs to store.
+This table is always located at pseudo-index
+LUA_REGISTRYINDEX.
+Any C library can store data into this table,
+but it should take care to choose keys different from those used
+by other libraries, to avoid collisions.
+Typically, you should use as key a string containing your library name
+or a light userdata with the address of a C object in your code.
+
+
+
+The integer keys in the registry are used by the reference mechanism, +implemented by the auxiliary library, +and therefore should not be used for other purposes. + + + + + +
+Internally, Lua uses the C longjmp facility to handle errors.
+(You can also choose to use exceptions if you use C++;
+see file luaconf.h.)
+When Lua faces any error
+(such as memory allocation errors, type errors, syntax errors,
+and runtime errors)
+it raises an error;
+that is, it does a long jump.
+A protected environment uses setjmp
+to set a recover point;
+any error jumps to the most recent active recover point.
+
+
+
+Most functions in the API may throw an error, +for instance due to a memory allocation error. +The documentation for each function indicates whether +it can throw errors. + + +
+Inside a C function you can throw an error by calling lua_error.
+
+
+
+
+
+
+Here we list all functions and types from the C API in +alphabetical order. +Each function has an indicator like this: +[-o, +p, x] + + +
+The first field, o,
+is how many elements the function pops from the stack.
+The second field, p,
+is how many elements the function pushes onto the stack.
+(Any function always pushes its results after popping its arguments.)
+A field in the form x|y means the function may push (or pop)
+x or y elements,
+depending on the situation;
+an interrogation mark '?' means that
+we cannot know how many elements the function pops/pushes
+by looking only at its arguments
+(e.g., they may depend on what is on the stack).
+The third field, x,
+tells whether the function may throw errors:
+'-' means the function never throws any error;
+'m' means the function may throw an error
+only due to not enough memory;
+'e' means the function may throw other kinds of errors;
+'v' means the function may throw an error on purpose.
+
+
+
+
lua_Alloctypedef void * (*lua_Alloc) (void *ud, + void *ptr, + size_t osize, + size_t nsize);+ +
+The type of the memory-allocation function used by Lua states.
+The allocator function must provide a
+functionality similar to realloc,
+but not exactly the same.
+Its arguments are
+ud, an opaque pointer passed to lua_newstate;
+ptr, a pointer to the block being allocated/reallocated/freed;
+osize, the original size of the block;
+nsize, the new size of the block.
+ptr is NULL if and only if osize is zero.
+When nsize is zero, the allocator must return NULL;
+if osize is not zero,
+it should free the block pointed to by ptr.
+When nsize is not zero, the allocator returns NULL
+if and only if it cannot fill the request.
+When nsize is not zero and osize is zero,
+the allocator should behave like malloc.
+When nsize and osize are not zero,
+the allocator behaves like realloc.
+Lua assumes that the allocator never fails when
+osize >= nsize.
+
+
+
+Here is a simple implementation for the allocator function.
+It is used in the auxiliary library by luaL_newstate.
+
+
+ static void *l_alloc (void *ud, void *ptr, size_t osize,
+ size_t nsize) {
+ (void)ud; (void)osize; /* not used */
+ if (nsize == 0) {
+ free(ptr);
+ return NULL;
+ }
+ else
+ return realloc(ptr, nsize);
+ }
+
+This code assumes
+that free(NULL) has no effect and that
+realloc(NULL, size) is equivalent to malloc(size).
+ANSI C ensures both behaviors.
+
+
+
+
+
+
lua_atpanic+[-0, +0, -] +
lua_CFunction lua_atpanic (lua_State *L, lua_CFunction panicf);+ +
+Sets a new panic function and returns the old one. + + +
+If an error happens outside any protected environment,
+Lua calls a panic function
+and then calls exit(EXIT_FAILURE),
+thus exiting the host application.
+Your panic function may avoid this exit by
+never returning (e.g., doing a long jump).
+
+
+
+The panic function can access the error message at the top of the stack. + + + + + +
lua_call+[-(nargs + 1), +nresults, e] +
void lua_call (lua_State *L, int nargs, int nresults);+ +
+Calls a function. + + +
+To call a function you must use the following protocol:
+first, the function to be called is pushed onto the stack;
+then, the arguments to the function are pushed
+in direct order;
+that is, the first argument is pushed first.
+Finally you call lua_call;
+nargs is the number of arguments that you pushed onto the stack.
+All arguments and the function value are popped from the stack
+when the function is called.
+The function results are pushed onto the stack when the function returns.
+The number of results is adjusted to nresults,
+unless nresults is LUA_MULTRET.
+In this case, all results from the function are pushed.
+Lua takes care that the returned values fit into the stack space.
+The function results are pushed onto the stack in direct order
+(the first result is pushed first),
+so that after the call the last result is on the top of the stack.
+
+
+
+Any error inside the called function is propagated upwards
+(with a longjmp).
+
+
+
+The following example shows how the host program may do the +equivalent to this Lua code: + +
+ a = f("how", t.x, 14)
++Here it is in C: + +
+ lua_getfield(L, LUA_GLOBALSINDEX, "f"); /* function to be called */ + lua_pushstring(L, "how"); /* 1st argument */ + lua_getfield(L, LUA_GLOBALSINDEX, "t"); /* table to be indexed */ + lua_getfield(L, -1, "x"); /* push result of t.x (2nd arg) */ + lua_remove(L, -2); /* remove 't' from the stack */ + lua_pushinteger(L, 14); /* 3rd argument */ + lua_call(L, 3, 1); /* call 'f' with 3 arguments and 1 result */ + lua_setfield(L, LUA_GLOBALSINDEX, "a"); /* set global 'a' */ +
+Note that the code above is "balanced": +at its end, the stack is back to its original configuration. +This is considered good programming practice. + + + + + +
lua_CFunctiontypedef int (*lua_CFunction) (lua_State *L);+ +
+Type for C functions. + + +
+In order to communicate properly with Lua,
+a C function must use the following protocol,
+which defines the way parameters and results are passed:
+a C function receives its arguments from Lua in its stack
+in direct order (the first argument is pushed first).
+So, when the function starts,
+lua_gettop(L) returns the number of arguments received by the function.
+The first argument (if any) is at index 1
+and its last argument is at index lua_gettop(L).
+To return values to Lua, a C function just pushes them onto the stack,
+in direct order (the first result is pushed first),
+and returns the number of results.
+Any other value in the stack below the results will be properly
+discarded by Lua.
+Like a Lua function, a C function called by Lua can also return
+many results.
+
+
+
+As an example, the following function receives a variable number +of numerical arguments and returns their average and sum: + +
+ static int foo (lua_State *L) {
+ int n = lua_gettop(L); /* number of arguments */
+ lua_Number sum = 0;
+ int i;
+ for (i = 1; i <= n; i++) {
+ if (!lua_isnumber(L, i)) {
+ lua_pushstring(L, "incorrect argument");
+ lua_error(L);
+ }
+ sum += lua_tonumber(L, i);
+ }
+ lua_pushnumber(L, sum/n); /* first result */
+ lua_pushnumber(L, sum); /* second result */
+ return 2; /* number of results */
+ }
+
+
+
+
+
+lua_checkstack+[-0, +0, m] +
int lua_checkstack (lua_State *L, int extra);+ +
+Ensures that there are at least extra free stack slots in the stack.
+It returns false if it cannot grow the stack to that size.
+This function never shrinks the stack;
+if the stack is already larger than the new size,
+it is left unchanged.
+
+
+
+
+
+
lua_close+[-0, +0, -] +
void lua_close (lua_State *L);+ +
+Destroys all objects in the given Lua state +(calling the corresponding garbage-collection metamethods, if any) +and frees all dynamic memory used by this state. +On several platforms, you may not need to call this function, +because all resources are naturally released when the host program ends. +On the other hand, long-running programs, +such as a daemon or a web server, +might need to release states as soon as they are not needed, +to avoid growing too large. + + + + + +
lua_concat+[-n, +1, e] +
void lua_concat (lua_State *L, int n);+ +
+Concatenates the n values at the top of the stack,
+pops them, and leaves the result at the top.
+If n is 1, the result is the single value on the stack
+(that is, the function does nothing);
+if n is 0, the result is the empty string.
+Concatenation is performed following the usual semantics of Lua
+(see §2.5.4).
+
+
+
+
+
+
lua_cpcall+[-0, +(0|1), -] +
int lua_cpcall (lua_State *L, lua_CFunction func, void *ud);+ +
+Calls the C function func in protected mode.
+func starts with only one element in its stack,
+a light userdata containing ud.
+In case of errors,
+lua_cpcall returns the same error codes as lua_pcall,
+plus the error object on the top of the stack;
+otherwise, it returns zero, and does not change the stack.
+All values returned by func are discarded.
+
+
+
+
+
+
lua_createtable+[-0, +1, m] +
void lua_createtable (lua_State *L, int narr, int nrec);+ +
+Creates a new empty table and pushes it onto the stack.
+The new table has space pre-allocated
+for narr array elements and nrec non-array elements.
+This pre-allocation is useful when you know exactly how many elements
+the table will have.
+Otherwise you can use the function lua_newtable.
+
+
+
+
+
+
lua_dump+[-0, +0, m] +
int lua_dump (lua_State *L, lua_Writer writer, void *data);+ +
+Dumps a function as a binary chunk.
+Receives a Lua function on the top of the stack
+and produces a binary chunk that,
+if loaded again,
+results in a function equivalent to the one dumped.
+As it produces parts of the chunk,
+lua_dump calls function writer (see lua_Writer)
+with the given data
+to write them.
+
+
+
+The value returned is the error code returned by the last +call to the writer; +0 means no errors. + + +
+This function does not pop the Lua function from the stack. + + + + + +
lua_equal+[-0, +0, e] +
int lua_equal (lua_State *L, int index1, int index2);+ +
+Returns 1 if the two values in acceptable indices index1 and
+index2 are equal,
+following the semantics of the Lua == operator
+(that is, may call metamethods).
+Otherwise returns 0.
+Also returns 0 if any of the indices is non valid.
+
+
+
+
+
+
lua_error+[-1, +0, v] +
int lua_error (lua_State *L);+ +
+Generates a Lua error.
+The error message (which can actually be a Lua value of any type)
+must be on the stack top.
+This function does a long jump,
+and therefore never returns.
+(see luaL_error).
+
+
+
+
+
+
lua_gc+[-0, +0, e] +
int lua_gc (lua_State *L, int what, int data);+ +
+Controls the garbage collector. + + +
+This function performs several tasks,
+according to the value of the parameter what:
+
+
LUA_GCSTOP:
+stops the garbage collector.
+LUA_GCRESTART:
+restarts the garbage collector.
+LUA_GCCOLLECT:
+performs a full garbage-collection cycle.
+LUA_GCCOUNT:
+returns the current amount of memory (in Kbytes) in use by Lua.
+LUA_GCCOUNTB:
+returns the remainder of dividing the current amount of bytes of
+memory in use by Lua by 1024.
+LUA_GCSTEP:
+performs an incremental step of garbage collection.
+The step "size" is controlled by data
+(larger values mean more steps) in a non-specified way.
+If you want to control the step size
+you must experimentally tune the value of data.
+The function returns 1 if the step finished a
+garbage-collection cycle.
+LUA_GCSETPAUSE:
+sets data/100 as the new value
+for the pause of the collector (see §2.10).
+The function returns the previous value of the pause.
+LUA_GCSETSTEPMUL:
+sets data/100 as the new value for the step multiplier of
+the collector (see §2.10).
+The function returns the previous value of the step multiplier.
+lua_getallocf+[-0, +0, -] +
lua_Alloc lua_getallocf (lua_State *L, void **ud);+ +
+Returns the memory-allocation function of a given state.
+If ud is not NULL, Lua stores in *ud the
+opaque pointer passed to lua_newstate.
+
+
+
+
+
+
lua_getfenv+[-0, +1, -] +
void lua_getfenv (lua_State *L, int index);+ +
+Pushes onto the stack the environment table of +the value at the given index. + + + + + +
lua_getfield+[-0, +1, e] +
void lua_getfield (lua_State *L, int index, const char *k);+ +
+Pushes onto the stack the value t[k],
+where t is the value at the given valid index.
+As in Lua, this function may trigger a metamethod
+for the "index" event (see §2.8).
+
+
+
+
+
+
lua_getglobal+[-0, +1, e] +
void lua_getglobal (lua_State *L, const char *name);+ +
+Pushes onto the stack the value of the global name.
+It is defined as a macro:
+
+
+ #define lua_getglobal(L,s) lua_getfield(L, LUA_GLOBALSINDEX, s) ++ + + + +
lua_getmetatable+[-0, +(0|1), -] +
int lua_getmetatable (lua_State *L, int index);+ +
+Pushes onto the stack the metatable of the value at the given +acceptable index. +If the index is not valid, +or if the value does not have a metatable, +the function returns 0 and pushes nothing on the stack. + + + + + +
lua_gettable+[-1, +1, e] +
void lua_gettable (lua_State *L, int index);+ +
+Pushes onto the stack the value t[k],
+where t is the value at the given valid index
+and k is the value at the top of the stack.
+
+
+
+This function pops the key from the stack +(putting the resulting value in its place). +As in Lua, this function may trigger a metamethod +for the "index" event (see §2.8). + + + + + +
lua_gettop+[-0, +0, -] +
int lua_gettop (lua_State *L);+ +
+Returns the index of the top element in the stack. +Because indices start at 1, +this result is equal to the number of elements in the stack +(and so 0 means an empty stack). + + + + + +
lua_insert+[-1, +1, -] +
void lua_insert (lua_State *L, int index);+ +
+Moves the top element into the given valid index, +shifting up the elements above this index to open space. +Cannot be called with a pseudo-index, +because a pseudo-index is not an actual stack position. + + + + + +
lua_Integertypedef ptrdiff_t lua_Integer;+ +
+The type used by the Lua API to represent integral values. + + +
+By default it is a ptrdiff_t,
+which is usually the largest signed integral type the machine handles
+"comfortably".
+
+
+
+
+
+
lua_isboolean+[-0, +0, -] +
int lua_isboolean (lua_State *L, int index);+ +
+Returns 1 if the value at the given acceptable index has type boolean, +and 0 otherwise. + + + + + +
lua_iscfunction+[-0, +0, -] +
int lua_iscfunction (lua_State *L, int index);+ +
+Returns 1 if the value at the given acceptable index is a C function, +and 0 otherwise. + + + + + +
lua_isfunction+[-0, +0, -] +
int lua_isfunction (lua_State *L, int index);+ +
+Returns 1 if the value at the given acceptable index is a function +(either C or Lua), and 0 otherwise. + + + + + +
lua_islightuserdata+[-0, +0, -] +
int lua_islightuserdata (lua_State *L, int index);+ +
+Returns 1 if the value at the given acceptable index is a light userdata, +and 0 otherwise. + + + + + +
lua_isnil+[-0, +0, -] +
int lua_isnil (lua_State *L, int index);+ +
+Returns 1 if the value at the given acceptable index is nil, +and 0 otherwise. + + + + + +
lua_isnone+[-0, +0, -] +
int lua_isnone (lua_State *L, int index);+ +
+Returns 1 if the given acceptable index is not valid +(that is, it refers to an element outside the current stack), +and 0 otherwise. + + + + + +
lua_isnoneornil+[-0, +0, -] +
int lua_isnoneornil (lua_State *L, int index);+ +
+Returns 1 if the given acceptable index is not valid +(that is, it refers to an element outside the current stack) +or if the value at this index is nil, +and 0 otherwise. + + + + + +
lua_isnumber+[-0, +0, -] +
int lua_isnumber (lua_State *L, int index);+ +
+Returns 1 if the value at the given acceptable index is a number +or a string convertible to a number, +and 0 otherwise. + + + + + +
lua_isstring+[-0, +0, -] +
int lua_isstring (lua_State *L, int index);+ +
+Returns 1 if the value at the given acceptable index is a string +or a number (which is always convertible to a string), +and 0 otherwise. + + + + + +
lua_istable+[-0, +0, -] +
int lua_istable (lua_State *L, int index);+ +
+Returns 1 if the value at the given acceptable index is a table, +and 0 otherwise. + + + + + +
lua_isthread+[-0, +0, -] +
int lua_isthread (lua_State *L, int index);+ +
+Returns 1 if the value at the given acceptable index is a thread, +and 0 otherwise. + + + + + +
lua_isuserdata+[-0, +0, -] +
int lua_isuserdata (lua_State *L, int index);+ +
+Returns 1 if the value at the given acceptable index is a userdata +(either full or light), and 0 otherwise. + + + + + +
lua_lessthan+[-0, +0, e] +
int lua_lessthan (lua_State *L, int index1, int index2);+ +
+Returns 1 if the value at acceptable index index1 is smaller
+than the value at acceptable index index2,
+following the semantics of the Lua < operator
+(that is, may call metamethods).
+Otherwise returns 0.
+Also returns 0 if any of the indices is non valid.
+
+
+
+
+
+
lua_load+[-0, +1, -] +
int lua_load (lua_State *L, + lua_Reader reader, + void *data, + const char *chunkname);+ +
+Loads a Lua chunk.
+If there are no errors,
+lua_load pushes the compiled chunk as a Lua
+function on top of the stack.
+Otherwise, it pushes an error message.
+The return values of lua_load are:
+
+
LUA_ERRSYNTAX:
+syntax error during pre-compilation;LUA_ERRMEM:
+memory allocation error.+This function only loads a chunk; +it does not run it. + + +
+lua_load automatically detects whether the chunk is text or binary,
+and loads it accordingly (see program luac).
+
+
+
+The lua_load function uses a user-supplied reader function
+to read the chunk (see lua_Reader).
+The data argument is an opaque value passed to the reader function.
+
+
+
+The chunkname argument gives a name to the chunk,
+which is used for error messages and in debug information (see §3.8).
+
+
+
+
+
+
lua_newstate+[-0, +0, -] +
lua_State *lua_newstate (lua_Alloc f, void *ud);+ +
+Creates a new, independent state.
+Returns NULL if cannot create the state
+(due to lack of memory).
+The argument f is the allocator function;
+Lua does all memory allocation for this state through this function.
+The second argument, ud, is an opaque pointer that Lua
+simply passes to the allocator in every call.
+
+
+
+
+
+
lua_newtable+[-0, +1, m] +
void lua_newtable (lua_State *L);+ +
+Creates a new empty table and pushes it onto the stack.
+It is equivalent to lua_createtable(L, 0, 0).
+
+
+
+
+
+
lua_newthread+[-0, +1, m] +
lua_State *lua_newthread (lua_State *L);+ +
+Creates a new thread, pushes it on the stack,
+and returns a pointer to a lua_State that represents this new thread.
+The new state returned by this function shares with the original state
+all global objects (such as tables),
+but has an independent execution stack.
+
+
+
+There is no explicit function to close or to destroy a thread. +Threads are subject to garbage collection, +like any Lua object. + + + + + +
lua_newuserdata+[-0, +1, m] +
void *lua_newuserdata (lua_State *L, size_t size);+ +
+This function allocates a new block of memory with the given size, +pushes onto the stack a new full userdata with the block address, +and returns this address. + + +
+Userdata represent C values in Lua. +A full userdata represents a block of memory. +It is an object (like a table): +you must create it, it can have its own metatable, +and you can detect when it is being collected. +A full userdata is only equal to itself (under raw equality). + + +
+When Lua collects a full userdata with a gc metamethod,
+Lua calls the metamethod and marks the userdata as finalized.
+When this userdata is collected again then
+Lua frees its corresponding memory.
+
+
+
+
+
+
lua_next+[-1, +(2|0), e] +
int lua_next (lua_State *L, int index);+ +
+Pops a key from the stack,
+and pushes a key-value pair from the table at the given index
+(the "next" pair after the given key).
+If there are no more elements in the table,
+then lua_next returns 0 (and pushes nothing).
+
+
+
+A typical traversal looks like this: + +
+ /* table is in the stack at index 't' */
+ lua_pushnil(L); /* first key */
+ while (lua_next(L, t) != 0) {
+ /* uses 'key' (at index -2) and 'value' (at index -1) */
+ printf("%s - %s\n",
+ lua_typename(L, lua_type(L, -2)),
+ lua_typename(L, lua_type(L, -1)));
+ /* removes 'value'; keeps 'key' for next iteration */
+ lua_pop(L, 1);
+ }
+
+
+
+While traversing a table,
+do not call lua_tolstring directly on a key,
+unless you know that the key is actually a string.
+Recall that lua_tolstring changes
+the value at the given index;
+this confuses the next call to lua_next.
+
+
+
+
+
+
lua_Numbertypedef double lua_Number;+ +
+The type of numbers in Lua.
+By default, it is double, but that can be changed in luaconf.h.
+
+
+
+Through the configuration file you can change +Lua to operate with another type for numbers (e.g., float or long). + + + + + +
lua_objlen+[-0, +0, -] +
size_t lua_objlen (lua_State *L, int index);+ +
+Returns the "length" of the value at the given acceptable index:
+for strings, this is the string length;
+for tables, this is the result of the length operator ('#');
+for userdata, this is the size of the block of memory allocated
+for the userdata;
+for other values, it is 0.
+
+
+
+
+
+
lua_pcall+[-(nargs + 1), +(nresults|1), -] +
int lua_pcall (lua_State *L, int nargs, int nresults, int errfunc);+ +
+Calls a function in protected mode. + + +
+Both nargs and nresults have the same meaning as
+in lua_call.
+If there are no errors during the call,
+lua_pcall behaves exactly like lua_call.
+However, if there is any error,
+lua_pcall catches it,
+pushes a single value on the stack (the error message),
+and returns an error code.
+Like lua_call,
+lua_pcall always removes the function
+and its arguments from the stack.
+
+
+
+If errfunc is 0,
+then the error message returned on the stack
+is exactly the original error message.
+Otherwise, errfunc is the stack index of an
+error handler function.
+(In the current implementation, this index cannot be a pseudo-index.)
+In case of runtime errors,
+this function will be called with the error message
+and its return value will be the message returned on the stack by lua_pcall.
+
+
+
+Typically, the error handler function is used to add more debug
+information to the error message, such as a stack traceback.
+Such information cannot be gathered after the return of lua_pcall,
+since by then the stack has unwound.
+
+
+
+The lua_pcall function returns 0 in case of success
+or one of the following error codes
+(defined in lua.h):
+
+
LUA_ERRRUN:
+a runtime error.
+LUA_ERRMEM:
+memory allocation error.
+For such errors, Lua does not call the error handler function.
+LUA_ERRERR:
+error while running the error handler function.
+lua_pop+[-n, +0, -] +
void lua_pop (lua_State *L, int n);+ +
+Pops n elements from the stack.
+
+
+
+
+
+
lua_pushboolean+[-0, +1, -] +
void lua_pushboolean (lua_State *L, int b);+ +
+Pushes a boolean value with value b onto the stack.
+
+
+
+
+
+
lua_pushcclosure+[-n, +1, m] +
void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n);+ +
+Pushes a new C closure onto the stack. + + +
+When a C function is created,
+it is possible to associate some values with it,
+thus creating a C closure (see §3.4);
+these values are then accessible to the function whenever it is called.
+To associate values with a C function,
+first these values should be pushed onto the stack
+(when there are multiple values, the first value is pushed first).
+Then lua_pushcclosure
+is called to create and push the C function onto the stack,
+with the argument n telling how many values should be
+associated with the function.
+lua_pushcclosure also pops these values from the stack.
+
+
+
+
+
+
lua_pushcfunction+[-0, +1, m] +
void lua_pushcfunction (lua_State *L, lua_CFunction f);+ +
+Pushes a C function onto the stack.
+This function receives a pointer to a C function
+and pushes onto the stack a Lua value of type function that,
+when called, invokes the corresponding C function.
+
+
+
+Any function to be registered in Lua must
+follow the correct protocol to receive its parameters
+and return its results (see lua_CFunction).
+
+
+
+lua_pushcfunction is defined as a macro:
+
+
+ #define lua_pushcfunction(L,f) lua_pushcclosure(L,f,0) ++ + + + +
lua_pushfstring+[-0, +1, m] +
const char *lua_pushfstring (lua_State *L, const char *fmt, ...);+ +
+Pushes onto the stack a formatted string
+and returns a pointer to this string.
+It is similar to the C function sprintf,
+but has some important differences:
+
+
%%' (inserts a '%' in the string),
+'%s' (inserts a zero-terminated string, with no size restrictions),
+'%f' (inserts a lua_Number),
+'%p' (inserts a pointer as a hexadecimal numeral),
+'%d' (inserts an int), and
+'%c' (inserts an int as a character).
+lua_pushinteger+[-0, +1, -] +
void lua_pushinteger (lua_State *L, lua_Integer n);+ +
+Pushes a number with value n onto the stack.
+
+
+
+
+
+
lua_pushlightuserdata+[-0, +1, -] +
void lua_pushlightuserdata (lua_State *L, void *p);+ +
+Pushes a light userdata onto the stack. + + +
+Userdata represent C values in Lua. +A light userdata represents a pointer. +It is a value (like a number): +you do not create it, it has no individual metatable, +and it is not collected (as it was never created). +A light userdata is equal to "any" +light userdata with the same C address. + + + + + +
lua_pushliteral+[-0, +1, m] +
void lua_pushliteral (lua_State *L, const char *s);+ +
+This macro is equivalent to lua_pushlstring,
+but can be used only when s is a literal string.
+In these cases, it automatically provides the string length.
+
+
+
+
+
+
lua_pushlstring+[-0, +1, m] +
void lua_pushlstring (lua_State *L, const char *s, size_t len);+ +
+Pushes the string pointed to by s with size len
+onto the stack.
+Lua makes (or reuses) an internal copy of the given string,
+so the memory at s can be freed or reused immediately after
+the function returns.
+The string can contain embedded zeros.
+
+
+
+
+
+
lua_pushnil+[-0, +1, -] +
void lua_pushnil (lua_State *L);+ +
+Pushes a nil value onto the stack. + + + + + +
lua_pushnumber+[-0, +1, -] +
void lua_pushnumber (lua_State *L, lua_Number n);+ +
+Pushes a number with value n onto the stack.
+
+
+
+
+
+
lua_pushstring+[-0, +1, m] +
void lua_pushstring (lua_State *L, const char *s);+ +
+Pushes the zero-terminated string pointed to by s
+onto the stack.
+Lua makes (or reuses) an internal copy of the given string,
+so the memory at s can be freed or reused immediately after
+the function returns.
+The string cannot contain embedded zeros;
+it is assumed to end at the first zero.
+
+
+
+
+
+
lua_pushthread+[-0, +1, -] +
int lua_pushthread (lua_State *L);+ +
+Pushes the thread represented by L onto the stack.
+Returns 1 if this thread is the main thread of its state.
+
+
+
+
+
+
lua_pushvalue+[-0, +1, -] +
void lua_pushvalue (lua_State *L, int index);+ +
+Pushes a copy of the element at the given valid index +onto the stack. + + + + + +
lua_pushvfstring+[-0, +1, m] +
const char *lua_pushvfstring (lua_State *L, + const char *fmt, + va_list argp);+ +
+Equivalent to lua_pushfstring, except that it receives a va_list
+instead of a variable number of arguments.
+
+
+
+
+
+
lua_rawequal+[-0, +0, -] +
int lua_rawequal (lua_State *L, int index1, int index2);+ +
+Returns 1 if the two values in acceptable indices index1 and
+index2 are primitively equal
+(that is, without calling metamethods).
+Otherwise returns 0.
+Also returns 0 if any of the indices are non valid.
+
+
+
+
+
+
lua_rawget+[-1, +1, -] +
void lua_rawget (lua_State *L, int index);+ +
+Similar to lua_gettable, but does a raw access
+(i.e., without metamethods).
+
+
+
+
+
+
lua_rawgeti+[-0, +1, -] +
void lua_rawgeti (lua_State *L, int index, int n);+ +
+Pushes onto the stack the value t[n],
+where t is the value at the given valid index.
+The access is raw;
+that is, it does not invoke metamethods.
+
+
+
+
+
+
lua_rawset+[-2, +0, m] +
void lua_rawset (lua_State *L, int index);+ +
+Similar to lua_settable, but does a raw assignment
+(i.e., without metamethods).
+
+
+
+
+
+
lua_rawseti+[-1, +0, m] +
void lua_rawseti (lua_State *L, int index, int n);+ +
+Does the equivalent of t[n] = v,
+where t is the value at the given valid index
+and v is the value at the top of the stack.
+
+
+
+This function pops the value from the stack. +The assignment is raw; +that is, it does not invoke metamethods. + + + + + +
lua_Readertypedef const char * (*lua_Reader) (lua_State *L, + void *data, + size_t *size);+ +
+The reader function used by lua_load.
+Every time it needs another piece of the chunk,
+lua_load calls the reader,
+passing along its data parameter.
+The reader must return a pointer to a block of memory
+with a new piece of the chunk
+and set size to the block size.
+The block must exist until the reader function is called again.
+To signal the end of the chunk, the reader must return NULL.
+The reader function may return pieces of any size greater than zero.
+
+
+
+
+
+
lua_register+[-0, +0, e] +
void lua_register (lua_State *L, + const char *name, + lua_CFunction f);+ +
+Sets the C function f as the new value of global name.
+It is defined as a macro:
+
+
+ #define lua_register(L,n,f) \ + (lua_pushcfunction(L, f), lua_setglobal(L, n)) ++ + + + +
lua_remove+[-1, +0, -] +
void lua_remove (lua_State *L, int index);+ +
+Removes the element at the given valid index, +shifting down the elements above this index to fill the gap. +Cannot be called with a pseudo-index, +because a pseudo-index is not an actual stack position. + + + + + +
lua_replace+[-1, +0, -] +
void lua_replace (lua_State *L, int index);+ +
+Moves the top element into the given position (and pops it), +without shifting any element +(therefore replacing the value at the given position). + + + + + +
lua_resume+[-?, +?, -] +
int lua_resume (lua_State *L, int narg);+ +
+Starts and resumes a coroutine in a given thread. + + +
+To start a coroutine, you first create a new thread
+(see lua_newthread);
+then you push onto its stack the main function plus any arguments;
+then you call lua_resume,
+with narg being the number of arguments.
+This call returns when the coroutine suspends or finishes its execution.
+When it returns, the stack contains all values passed to lua_yield,
+or all values returned by the body function.
+lua_resume returns
+LUA_YIELD if the coroutine yields,
+0 if the coroutine finishes its execution
+without errors,
+or an error code in case of errors (see lua_pcall).
+In case of errors,
+the stack is not unwound,
+so you can use the debug API over it.
+The error message is on the top of the stack.
+To restart a coroutine, you put on its stack only the values to
+be passed as results from yield,
+and then call lua_resume.
+
+
+
+
+
+
lua_setallocf+[-0, +0, -] +
void lua_setallocf (lua_State *L, lua_Alloc f, void *ud);+ +
+Changes the allocator function of a given state to f
+with user data ud.
+
+
+
+
+
+
lua_setfenv+[-1, +0, -] +
int lua_setfenv (lua_State *L, int index);+ +
+Pops a table from the stack and sets it as
+the new environment for the value at the given index.
+If the value at the given index is
+neither a function nor a thread nor a userdata,
+lua_setfenv returns 0.
+Otherwise it returns 1.
+
+
+
+
+
+
lua_setfield+[-1, +0, e] +
void lua_setfield (lua_State *L, int index, const char *k);+ +
+Does the equivalent to t[k] = v,
+where t is the value at the given valid index
+and v is the value at the top of the stack.
+
+
+
+This function pops the value from the stack. +As in Lua, this function may trigger a metamethod +for the "newindex" event (see §2.8). + + + + + +
lua_setglobal+[-1, +0, e] +
void lua_setglobal (lua_State *L, const char *name);+ +
+Pops a value from the stack and
+sets it as the new value of global name.
+It is defined as a macro:
+
+
+ #define lua_setglobal(L,s) lua_setfield(L, LUA_GLOBALSINDEX, s) ++ + + + +
lua_setmetatable+[-1, +0, -] +
int lua_setmetatable (lua_State *L, int index);+ +
+Pops a table from the stack and +sets it as the new metatable for the value at the given +acceptable index. + + + + + +
lua_settable+[-2, +0, e] +
void lua_settable (lua_State *L, int index);+ +
+Does the equivalent to t[k] = v,
+where t is the value at the given valid index,
+v is the value at the top of the stack,
+and k is the value just below the top.
+
+
+
+This function pops both the key and the value from the stack. +As in Lua, this function may trigger a metamethod +for the "newindex" event (see §2.8). + + + + + +
lua_settop+[-?, +?, -] +
void lua_settop (lua_State *L, int index);+ +
+Accepts any acceptable index, or 0,
+and sets the stack top to this index.
+If the new top is larger than the old one,
+then the new elements are filled with nil.
+If index is 0, then all stack elements are removed.
+
+
+
+
+
+
lua_Statetypedef struct lua_State lua_State;+ +
+Opaque structure that keeps the whole state of a Lua interpreter. +The Lua library is fully reentrant: +it has no global variables. +All information about a state is kept in this structure. + + +
+A pointer to this state must be passed as the first argument to
+every function in the library, except to lua_newstate,
+which creates a Lua state from scratch.
+
+
+
+
+
+
lua_status+[-0, +0, -] +
int lua_status (lua_State *L);+ +
+Returns the status of the thread L.
+
+
+
+The status can be 0 for a normal thread,
+an error code if the thread finished its execution with an error,
+or LUA_YIELD if the thread is suspended.
+
+
+
+
+
+
lua_toboolean+[-0, +0, -] +
int lua_toboolean (lua_State *L, int index);+ +
+Converts the Lua value at the given acceptable index to a C boolean
+value (0 or 1).
+Like all tests in Lua,
+lua_toboolean returns 1 for any Lua value
+different from false and nil;
+otherwise it returns 0.
+It also returns 0 when called with a non-valid index.
+(If you want to accept only actual boolean values,
+use lua_isboolean to test the value's type.)
+
+
+
+
+
+
lua_tocfunction+[-0, +0, -] +
lua_CFunction lua_tocfunction (lua_State *L, int index);+ +
+Converts a value at the given acceptable index to a C function.
+That value must be a C function;
+otherwise, returns NULL.
+
+
+
+
+
+
lua_tointeger+[-0, +0, -] +
lua_Integer lua_tointeger (lua_State *L, int index);+ +
+Converts the Lua value at the given acceptable index
+to the signed integral type lua_Integer.
+The Lua value must be a number or a string convertible to a number
+(see §2.2.1);
+otherwise, lua_tointeger returns 0.
+
+
+
+If the number is not an integer, +it is truncated in some non-specified way. + + + + + +
lua_tolstring+[-0, +0, m] +
const char *lua_tolstring (lua_State *L, int index, size_t *len);+ +
+Converts the Lua value at the given acceptable index to a C string.
+If len is not NULL,
+it also sets *len with the string length.
+The Lua value must be a string or a number;
+otherwise, the function returns NULL.
+If the value is a number,
+then lua_tolstring also
+changes the actual value in the stack to a string.
+(This change confuses lua_next
+when lua_tolstring is applied to keys during a table traversal.)
+
+
+
+lua_tolstring returns a fully aligned pointer
+to a string inside the Lua state.
+This string always has a zero ('\0')
+after its last character (as in C),
+but may contain other zeros in its body.
+Because Lua has garbage collection,
+there is no guarantee that the pointer returned by lua_tolstring
+will be valid after the corresponding value is removed from the stack.
+
+
+
+
+
+
lua_tonumber+[-0, +0, -] +
lua_Number lua_tonumber (lua_State *L, int index);+ +
+Converts the Lua value at the given acceptable index
+to the C type lua_Number (see lua_Number).
+The Lua value must be a number or a string convertible to a number
+(see §2.2.1);
+otherwise, lua_tonumber returns 0.
+
+
+
+
+
+
lua_topointer+[-0, +0, -] +
const void *lua_topointer (lua_State *L, int index);+ +
+Converts the value at the given acceptable index to a generic
+C pointer (void*).
+The value may be a userdata, a table, a thread, or a function;
+otherwise, lua_topointer returns NULL.
+Different objects will give different pointers.
+There is no way to convert the pointer back to its original value.
+
+
+
+Typically this function is used only for debug information. + + + + + +
lua_tostring+[-0, +0, m] +
const char *lua_tostring (lua_State *L, int index);+ +
+Equivalent to lua_tolstring with len equal to NULL.
+
+
+
+
+
+
lua_tothread+[-0, +0, -] +
lua_State *lua_tothread (lua_State *L, int index);+ +
+Converts the value at the given acceptable index to a Lua thread
+(represented as lua_State*).
+This value must be a thread;
+otherwise, the function returns NULL.
+
+
+
+
+
+
lua_touserdata+[-0, +0, -] +
void *lua_touserdata (lua_State *L, int index);+ +
+If the value at the given acceptable index is a full userdata,
+returns its block address.
+If the value is a light userdata,
+returns its pointer.
+Otherwise, returns NULL.
+
+
+
+
+
+
lua_type+[-0, +0, -] +
int lua_type (lua_State *L, int index);+ +
+Returns the type of the value in the given acceptable index,
+or LUA_TNONE for a non-valid index
+(that is, an index to an "empty" stack position).
+The types returned by lua_type are coded by the following constants
+defined in lua.h:
+LUA_TNIL,
+LUA_TNUMBER,
+LUA_TBOOLEAN,
+LUA_TSTRING,
+LUA_TTABLE,
+LUA_TFUNCTION,
+LUA_TUSERDATA,
+LUA_TTHREAD,
+and
+LUA_TLIGHTUSERDATA.
+
+
+
+
+
+
lua_typename+[-0, +0, -] +
const char *lua_typename (lua_State *L, int tp);+ +
+Returns the name of the type encoded by the value tp,
+which must be one the values returned by lua_type.
+
+
+
+
+
+
lua_Writertypedef int (*lua_Writer) (lua_State *L, + const void* p, + size_t sz, + void* ud);+ +
+The type of the writer function used by lua_dump.
+Every time it produces another piece of chunk,
+lua_dump calls the writer,
+passing along the buffer to be written (p),
+its size (sz),
+and the data parameter supplied to lua_dump.
+
+
+
+The writer returns an error code:
+0 means no errors;
+any other value means an error and stops lua_dump from
+calling the writer again.
+
+
+
+
+
+
lua_xmove+[-?, +?, -] +
void lua_xmove (lua_State *from, lua_State *to, int n);+ +
+Exchange values between different threads of the same global state. + + +
+This function pops n values from the stack from,
+and pushes them onto the stack to.
+
+
+
+
+
+
lua_yield+[-?, +?, -] +
int lua_yield (lua_State *L, int nresults);+ +
+Yields a coroutine. + + +
+This function should only be called as the +return expression of a C function, as follows: + +
+ return lua_yield (L, nresults); +
+When a C function calls lua_yield in that way,
+the running coroutine suspends its execution,
+and the call to lua_resume that started this coroutine returns.
+The parameter nresults is the number of values from the stack
+that are passed as results to lua_resume.
+
+
+
+
+
+
+
+
+Lua has no built-in debugging facilities. +Instead, it offers a special interface +by means of functions and hooks. +This interface allows the construction of different +kinds of debuggers, profilers, and other tools +that need "inside information" from the interpreter. + + + +
lua_Debugtypedef struct lua_Debug {
+ int event;
+ const char *name; /* (n) */
+ const char *namewhat; /* (n) */
+ const char *what; /* (S) */
+ const char *source; /* (S) */
+ int currentline; /* (l) */
+ int nups; /* (u) number of upvalues */
+ int linedefined; /* (S) */
+ int lastlinedefined; /* (S) */
+ char short_src[LUA_IDSIZE]; /* (S) */
+ /* private part */
+ other fields
+} lua_Debug;
+
+
+A structure used to carry different pieces of
+information about an active function.
+lua_getstack fills only the private part
+of this structure, for later use.
+To fill the other fields of lua_Debug with useful information,
+call lua_getinfo.
+
+
+
+The fields of lua_Debug have the following meaning:
+
+
source:
+If the function was defined in a string,
+then source is that string.
+If the function was defined in a file,
+then source starts with a '@' followed by the file name.
+short_src:
+a "printable" version of source, to be used in error messages.
+linedefined:
+the line number where the definition of the function starts.
+lastlinedefined:
+the line number where the definition of the function ends.
+what:
+the string "Lua" if the function is a Lua function,
+"C" if it is a C function,
+"main" if it is the main part of a chunk,
+and "tail" if it was a function that did a tail call.
+In the latter case,
+Lua has no other information about the function.
+currentline:
+the current line where the given function is executing.
+When no line information is available,
+currentline is set to -1.
+name:
+a reasonable name for the given function.
+Because functions in Lua are first-class values,
+they do not have a fixed name:
+some functions may be the value of multiple global variables,
+while others may be stored only in a table field.
+The lua_getinfo function checks how the function was
+called to find a suitable name.
+If it cannot find a name,
+then name is set to NULL.
+namewhat:
+explains the name field.
+The value of namewhat can be
+"global", "local", "method",
+"field", "upvalue", or "" (the empty string),
+according to how the function was called.
+(Lua uses the empty string when no other option seems to apply.)
+nups:
+the number of upvalues of the function.
+lua_gethook+[-0, +0, -] +
lua_Hook lua_gethook (lua_State *L);+ +
+Returns the current hook function. + + + + + +
lua_gethookcount+[-0, +0, -] +
int lua_gethookcount (lua_State *L);+ +
+Returns the current hook count. + + + + + +
lua_gethookmask+[-0, +0, -] +
int lua_gethookmask (lua_State *L);+ +
+Returns the current hook mask. + + + + + +
lua_getinfo+[-(0|1), +(0|1|2), m] +
int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar);+ +
+Returns information about a specific function or function invocation. + + +
+To get information about a function invocation,
+the parameter ar must be a valid activation record that was
+filled by a previous call to lua_getstack or
+given as argument to a hook (see lua_Hook).
+
+
+
+To get information about a function you push it onto the stack
+and start the what string with the character '>'.
+(In that case,
+lua_getinfo pops the function in the top of the stack.)
+For instance, to know in which line a function f was defined,
+you can write the following code:
+
+
+ lua_Debug ar;
+ lua_getfield(L, LUA_GLOBALSINDEX, "f"); /* get global 'f' */
+ lua_getinfo(L, ">S", &ar);
+ printf("%d\n", ar.linedefined);
+
+
+
+Each character in the string what
+selects some fields of the structure ar to be filled or
+a value to be pushed on the stack:
+
+
n': fills in the field name and namewhat;
+S':
+fills in the fields source, short_src,
+linedefined, lastlinedefined, and what;
+l': fills in the field currentline;
+u': fills in the field nups;
+f':
+pushes onto the stack the function that is
+running at the given level;
+L':
+pushes onto the stack a table whose indices are the
+numbers of the lines that are valid on the function.
+(A valid line is a line with some associated code,
+that is, a line where you can put a break point.
+Non-valid lines include empty lines and comments.)
+
+This function returns 0 on error
+(for instance, an invalid option in what).
+
+
+
+
+
+
lua_getlocal+[-0, +(0|1), -] +
const char *lua_getlocal (lua_State *L, lua_Debug *ar, int n);+ +
+Gets information about a local variable of a given activation record.
+The parameter ar must be a valid activation record that was
+filled by a previous call to lua_getstack or
+given as argument to a hook (see lua_Hook).
+The index n selects which local variable to inspect
+(1 is the first parameter or active local variable, and so on,
+until the last active local variable).
+lua_getlocal pushes the variable's value onto the stack
+and returns its name.
+
+
+
+Variable names starting with '(' (open parentheses)
+represent internal variables
+(loop control variables, temporaries, and C function locals).
+
+
+
+Returns NULL (and pushes nothing)
+when the index is greater than
+the number of active local variables.
+
+
+
+
+
+
lua_getstack+[-0, +0, -] +
int lua_getstack (lua_State *L, int level, lua_Debug *ar);+ +
+Get information about the interpreter runtime stack. + + +
+This function fills parts of a lua_Debug structure with
+an identification of the activation record
+of the function executing at a given level.
+Level 0 is the current running function,
+whereas level n+1 is the function that has called level n.
+When there are no errors, lua_getstack returns 1;
+when called with a level greater than the stack depth,
+it returns 0.
+
+
+
+
+
+
lua_getupvalue+[-0, +(0|1), -] +
const char *lua_getupvalue (lua_State *L, int funcindex, int n);+ +
+Gets information about a closure's upvalue.
+(For Lua functions,
+upvalues are the external local variables that the function uses,
+and that are consequently included in its closure.)
+lua_getupvalue gets the index n of an upvalue,
+pushes the upvalue's value onto the stack,
+and returns its name.
+funcindex points to the closure in the stack.
+(Upvalues have no particular order,
+as they are active through the whole function.
+So, they are numbered in an arbitrary order.)
+
+
+
+Returns NULL (and pushes nothing)
+when the index is greater than the number of upvalues.
+For C functions, this function uses the empty string ""
+as a name for all upvalues.
+
+
+
+
+
+
lua_Hooktypedef void (*lua_Hook) (lua_State *L, lua_Debug *ar);+ +
+Type for debugging hook functions. + + +
+Whenever a hook is called, its ar argument has its field
+event set to the specific event that triggered the hook.
+Lua identifies these events with the following constants:
+LUA_HOOKCALL, LUA_HOOKRET,
+LUA_HOOKTAILRET, LUA_HOOKLINE,
+and LUA_HOOKCOUNT.
+Moreover, for line events, the field currentline is also set.
+To get the value of any other field in ar,
+the hook must call lua_getinfo.
+For return events, event may be LUA_HOOKRET,
+the normal value, or LUA_HOOKTAILRET.
+In the latter case, Lua is simulating a return from
+a function that did a tail call;
+in this case, it is useless to call lua_getinfo.
+
+
+
+While Lua is running a hook, it disables other calls to hooks. +Therefore, if a hook calls back Lua to execute a function or a chunk, +this execution occurs without any calls to hooks. + + + + + +
lua_sethook+[-0, +0, -] +
int lua_sethook (lua_State *L, lua_Hook f, int mask, int count);+ +
+Sets the debugging hook function. + + +
+Argument f is the hook function.
+mask specifies on which events the hook will be called:
+it is formed by a bitwise or of the constants
+LUA_MASKCALL,
+LUA_MASKRET,
+LUA_MASKLINE,
+and LUA_MASKCOUNT.
+The count argument is only meaningful when the mask
+includes LUA_MASKCOUNT.
+For each event, the hook is called as explained below:
+
+
count instructions.
+(This event only happens while Lua is executing a Lua function.)
+
+A hook is disabled by setting mask to zero.
+
+
+
+
+
+
lua_setlocal+[-(0|1), +0, -] +
const char *lua_setlocal (lua_State *L, lua_Debug *ar, int n);+ +
+Sets the value of a local variable of a given activation record.
+Parameters ar and n are as in lua_getlocal
+(see lua_getlocal).
+lua_setlocal assigns the value at the top of the stack
+to the variable and returns its name.
+It also pops the value from the stack.
+
+
+
+Returns NULL (and pops nothing)
+when the index is greater than
+the number of active local variables.
+
+
+
+
+
+
lua_setupvalue+[-(0|1), +0, -] +
const char *lua_setupvalue (lua_State *L, int funcindex, int n);+ +
+Sets the value of a closure's upvalue.
+It assigns the value at the top of the stack
+to the upvalue and returns its name.
+It also pops the value from the stack.
+Parameters funcindex and n are as in the lua_getupvalue
+(see lua_getupvalue).
+
+
+
+Returns NULL (and pops nothing)
+when the index is greater than the number of upvalues.
+
+
+
+
+
+
+
+
+ +The auxiliary library provides several convenient functions +to interface C with Lua. +While the basic API provides the primitive functions for all +interactions between C and Lua, +the auxiliary library provides higher-level functions for some +common tasks. + + +
+All functions from the auxiliary library
+are defined in header file lauxlib.h and
+have a prefix luaL_.
+
+
+
+All functions in the auxiliary library are built on +top of the basic API, +and so they provide nothing that cannot be done with this API. + + +
+Several functions in the auxiliary library are used to
+check C function arguments.
+Their names are always luaL_check* or luaL_opt*.
+All of these functions throw an error if the check is not satisfied.
+Because the error message is formatted for arguments
+(e.g., "bad argument #1"),
+you should not use these functions for other stack values.
+
+
+
+
+Here we list all functions and types from the auxiliary library +in alphabetical order. + + + +
luaL_addchar+[-0, +0, m] +
void luaL_addchar (luaL_Buffer *B, char c);+ +
+Adds the character c to the buffer B
+(see luaL_Buffer).
+
+
+
+
+
+
luaL_addlstring+[-0, +0, m] +
void luaL_addlstring (luaL_Buffer *B, const char *s, size_t l);+ +
+Adds the string pointed to by s with length l to
+the buffer B
+(see luaL_Buffer).
+The string may contain embedded zeros.
+
+
+
+
+
+
luaL_addsize+[-0, +0, m] +
void luaL_addsize (luaL_Buffer *B, size_t n);+ +
+Adds to the buffer B (see luaL_Buffer)
+a string of length n previously copied to the
+buffer area (see luaL_prepbuffer).
+
+
+
+
+
+
luaL_addstring+[-0, +0, m] +
void luaL_addstring (luaL_Buffer *B, const char *s);+ +
+Adds the zero-terminated string pointed to by s
+to the buffer B
+(see luaL_Buffer).
+The string may not contain embedded zeros.
+
+
+
+
+
+
luaL_addvalue+[-1, +0, m] +
void luaL_addvalue (luaL_Buffer *B);+ +
+Adds the value at the top of the stack
+to the buffer B
+(see luaL_Buffer).
+Pops the value.
+
+
+
+This is the only function on string buffers that can (and must) +be called with an extra element on the stack, +which is the value to be added to the buffer. + + + + + +
luaL_argcheck+[-0, +0, v] +
void luaL_argcheck (lua_State *L, + int cond, + int narg, + const char *extramsg);+ +
+Checks whether cond is true.
+If not, raises an error with the following message,
+where func is retrieved from the call stack:
+
+
+ bad argument #<narg> to <func> (<extramsg>) ++ + + + +
luaL_argerror+[-0, +0, v] +
int luaL_argerror (lua_State *L, int narg, const char *extramsg);+ +
+Raises an error with the following message,
+where func is retrieved from the call stack:
+
+
+ bad argument #<narg> to <func> (<extramsg>) ++ +
+This function never returns,
+but it is an idiom to use it in C functions
+as return luaL_argerror(args).
+
+
+
+
+
+
luaL_Buffertypedef struct luaL_Buffer luaL_Buffer;+ +
+Type for a string buffer. + + +
+A string buffer allows C code to build Lua strings piecemeal. +Its pattern of use is as follows: + +
b of type luaL_Buffer.luaL_buffinit(L, &b).luaL_add* functions.
+luaL_pushresult(&b).
+This call leaves the final string on the top of the stack.
+
+During its normal operation,
+a string buffer uses a variable number of stack slots.
+So, while using a buffer, you cannot assume that you know where
+the top of the stack is.
+You can use the stack between successive calls to buffer operations
+as long as that use is balanced;
+that is,
+when you call a buffer operation,
+the stack is at the same level
+it was immediately after the previous buffer operation.
+(The only exception to this rule is luaL_addvalue.)
+After calling luaL_pushresult the stack is back to its
+level when the buffer was initialized,
+plus the final string on its top.
+
+
+
+
+
+
luaL_buffinit+[-0, +0, -] +
void luaL_buffinit (lua_State *L, luaL_Buffer *B);+ +
+Initializes a buffer B.
+This function does not allocate any space;
+the buffer must be declared as a variable
+(see luaL_Buffer).
+
+
+
+
+
+
luaL_callmeta+[-0, +(0|1), e] +
int luaL_callmeta (lua_State *L, int obj, const char *e);+ +
+Calls a metamethod. + + +
+If the object at index obj has a metatable and this
+metatable has a field e,
+this function calls this field and passes the object as its only argument.
+In this case this function returns 1 and pushes onto the
+stack the value returned by the call.
+If there is no metatable or no metamethod,
+this function returns 0 (without pushing any value on the stack).
+
+
+
+
+
+
luaL_checkany+[-0, +0, v] +
void luaL_checkany (lua_State *L, int narg);+ +
+Checks whether the function has an argument
+of any type (including nil) at position narg.
+
+
+
+
+
+
luaL_checkint+[-0, +0, v] +
int luaL_checkint (lua_State *L, int narg);+ +
+Checks whether the function argument narg is a number
+and returns this number cast to an int.
+
+
+
+
+
+
luaL_checkinteger+[-0, +0, v] +
lua_Integer luaL_checkinteger (lua_State *L, int narg);+ +
+Checks whether the function argument narg is a number
+and returns this number cast to a lua_Integer.
+
+
+
+
+
+
luaL_checklong+[-0, +0, v] +
long luaL_checklong (lua_State *L, int narg);+ +
+Checks whether the function argument narg is a number
+and returns this number cast to a long.
+
+
+
+
+
+
luaL_checklstring+[-0, +0, v] +
const char *luaL_checklstring (lua_State *L, int narg, size_t *l);+ +
+Checks whether the function argument narg is a string
+and returns this string;
+if l is not NULL fills *l
+with the string's length.
+
+
+
+This function uses lua_tolstring to get its result,
+so all conversions and caveats of that function apply here.
+
+
+
+
+
+
luaL_checknumber+[-0, +0, v] +
lua_Number luaL_checknumber (lua_State *L, int narg);+ +
+Checks whether the function argument narg is a number
+and returns this number.
+
+
+
+
+
+
luaL_checkoption+[-0, +0, v] +
int luaL_checkoption (lua_State *L, + int narg, + const char *def, + const char *const lst[]);+ +
+Checks whether the function argument narg is a string and
+searches for this string in the array lst
+(which must be NULL-terminated).
+Returns the index in the array where the string was found.
+Raises an error if the argument is not a string or
+if the string cannot be found.
+
+
+
+If def is not NULL,
+the function uses def as a default value when
+there is no argument narg or if this argument is nil.
+
+
+
+This is a useful function for mapping strings to C enums. +(The usual convention in Lua libraries is +to use strings instead of numbers to select options.) + + + + + +
luaL_checkstack+[-0, +0, v] +
void luaL_checkstack (lua_State *L, int sz, const char *msg);+ +
+Grows the stack size to top + sz elements,
+raising an error if the stack cannot grow to that size.
+msg is an additional text to go into the error message.
+
+
+
+
+
+
luaL_checkstring+[-0, +0, v] +
const char *luaL_checkstring (lua_State *L, int narg);+ +
+Checks whether the function argument narg is a string
+and returns this string.
+
+
+
+This function uses lua_tolstring to get its result,
+so all conversions and caveats of that function apply here.
+
+
+
+
+
+
luaL_checktype+[-0, +0, v] +
void luaL_checktype (lua_State *L, int narg, int t);+ +
+Checks whether the function argument narg has type t.
+See lua_type for the encoding of types for t.
+
+
+
+
+
+
luaL_checkudata+[-0, +0, v] +
void *luaL_checkudata (lua_State *L, int narg, const char *tname);+ +
+Checks whether the function argument narg is a userdata
+of the type tname (see luaL_newmetatable).
+
+
+
+
+
+
luaL_dofile+[-0, +?, m] +
int luaL_dofile (lua_State *L, const char *filename);+ +
+Loads and runs the given file. +It is defined as the following macro: + +
+ (luaL_loadfile(L, filename) || lua_pcall(L, 0, LUA_MULTRET, 0)) +
+It returns 0 if there are no errors +or 1 in case of errors. + + + + + +
luaL_dostring+[-0, +?, m] +
int luaL_dostring (lua_State *L, const char *str);+ +
+Loads and runs the given string. +It is defined as the following macro: + +
+ (luaL_loadstring(L, str) || lua_pcall(L, 0, LUA_MULTRET, 0)) +
+It returns 0 if there are no errors +or 1 in case of errors. + + + + + +
luaL_error+[-0, +0, v] +
int luaL_error (lua_State *L, const char *fmt, ...);+ +
+Raises an error.
+The error message format is given by fmt
+plus any extra arguments,
+following the same rules of lua_pushfstring.
+It also adds at the beginning of the message the file name and
+the line number where the error occurred,
+if this information is available.
+
+
+
+This function never returns,
+but it is an idiom to use it in C functions
+as return luaL_error(args).
+
+
+
+
+
+
luaL_getmetafield+[-0, +(0|1), m] +
int luaL_getmetafield (lua_State *L, int obj, const char *e);+ +
+Pushes onto the stack the field e from the metatable
+of the object at index obj.
+If the object does not have a metatable,
+or if the metatable does not have this field,
+returns 0 and pushes nothing.
+
+
+
+
+
+
luaL_getmetatable+[-0, +1, -] +
void luaL_getmetatable (lua_State *L, const char *tname);+ +
+Pushes onto the stack the metatable associated with name tname
+in the registry (see luaL_newmetatable).
+
+
+
+
+
+
luaL_gsub+[-0, +1, m] +
const char *luaL_gsub (lua_State *L, + const char *s, + const char *p, + const char *r);+ +
+Creates a copy of string s by replacing
+any occurrence of the string p
+with the string r.
+Pushes the resulting string on the stack and returns it.
+
+
+
+
+
+
luaL_loadbuffer+[-0, +1, m] +
int luaL_loadbuffer (lua_State *L, + const char *buff, + size_t sz, + const char *name);+ +
+Loads a buffer as a Lua chunk.
+This function uses lua_load to load the chunk in the
+buffer pointed to by buff with size sz.
+
+
+
+This function returns the same results as lua_load.
+name is the chunk name,
+used for debug information and error messages.
+
+
+
+
+
+
luaL_loadfile+[-0, +1, m] +
int luaL_loadfile (lua_State *L, const char *filename);+ +
+Loads a file as a Lua chunk.
+This function uses lua_load to load the chunk in the file
+named filename.
+If filename is NULL,
+then it loads from the standard input.
+The first line in the file is ignored if it starts with a #.
+
+
+
+This function returns the same results as lua_load,
+but it has an extra error code LUA_ERRFILE
+if it cannot open/read the file.
+
+
+
+As lua_load, this function only loads the chunk;
+it does not run it.
+
+
+
+
+
+
luaL_loadstring+[-0, +1, m] +
int luaL_loadstring (lua_State *L, const char *s);+ +
+Loads a string as a Lua chunk.
+This function uses lua_load to load the chunk in
+the zero-terminated string s.
+
+
+
+This function returns the same results as lua_load.
+
+
+
+Also as lua_load, this function only loads the chunk;
+it does not run it.
+
+
+
+
+
+
luaL_newmetatable+[-0, +1, m] +
int luaL_newmetatable (lua_State *L, const char *tname);+ +
+If the registry already has the key tname,
+returns 0.
+Otherwise,
+creates a new table to be used as a metatable for userdata,
+adds it to the registry with key tname,
+and returns 1.
+
+
+
+In both cases pushes onto the stack the final value associated
+with tname in the registry.
+
+
+
+
+
+
luaL_newstate+[-0, +0, -] +
lua_State *luaL_newstate (void);+ +
+Creates a new Lua state.
+It calls lua_newstate with an
+allocator based on the standard C realloc function
+and then sets a panic function (see lua_atpanic) that prints
+an error message to the standard error output in case of fatal
+errors.
+
+
+
+Returns the new state,
+or NULL if there is a memory allocation error.
+
+
+
+
+
+
luaL_openlibs+[-0, +0, m] +
void luaL_openlibs (lua_State *L);+ +
+Opens all standard Lua libraries into the given state. + + + + + +
luaL_optint+[-0, +0, v] +
int luaL_optint (lua_State *L, int narg, int d);+ +
+If the function argument narg is a number,
+returns this number cast to an int.
+If this argument is absent or is nil,
+returns d.
+Otherwise, raises an error.
+
+
+
+
+
+
luaL_optinteger+[-0, +0, v] +
lua_Integer luaL_optinteger (lua_State *L, + int narg, + lua_Integer d);+ +
+If the function argument narg is a number,
+returns this number cast to a lua_Integer.
+If this argument is absent or is nil,
+returns d.
+Otherwise, raises an error.
+
+
+
+
+
+
luaL_optlong+[-0, +0, v] +
long luaL_optlong (lua_State *L, int narg, long d);+ +
+If the function argument narg is a number,
+returns this number cast to a long.
+If this argument is absent or is nil,
+returns d.
+Otherwise, raises an error.
+
+
+
+
+
+
luaL_optlstring+[-0, +0, v] +
const char *luaL_optlstring (lua_State *L, + int narg, + const char *d, + size_t *l);+ +
+If the function argument narg is a string,
+returns this string.
+If this argument is absent or is nil,
+returns d.
+Otherwise, raises an error.
+
+
+
+If l is not NULL,
+fills the position *l with the results's length.
+
+
+
+
+
+
luaL_optnumber+[-0, +0, v] +
lua_Number luaL_optnumber (lua_State *L, int narg, lua_Number d);+ +
+If the function argument narg is a number,
+returns this number.
+If this argument is absent or is nil,
+returns d.
+Otherwise, raises an error.
+
+
+
+
+
+
luaL_optstring+[-0, +0, v] +
const char *luaL_optstring (lua_State *L, + int narg, + const char *d);+ +
+If the function argument narg is a string,
+returns this string.
+If this argument is absent or is nil,
+returns d.
+Otherwise, raises an error.
+
+
+
+
+
+
luaL_prepbuffer+[-0, +0, -] +
char *luaL_prepbuffer (luaL_Buffer *B);+ +
+Returns an address to a space of size LUAL_BUFFERSIZE
+where you can copy a string to be added to buffer B
+(see luaL_Buffer).
+After copying the string into this space you must call
+luaL_addsize with the size of the string to actually add
+it to the buffer.
+
+
+
+
+
+
luaL_pushresult+[-?, +1, m] +
void luaL_pushresult (luaL_Buffer *B);+ +
+Finishes the use of buffer B leaving the final string on
+the top of the stack.
+
+
+
+
+
+
luaL_ref+[-1, +0, m] +
int luaL_ref (lua_State *L, int t);+ +
+Creates and returns a reference,
+in the table at index t,
+for the object at the top of the stack (and pops the object).
+
+
+
+A reference is a unique integer key.
+As long as you do not manually add integer keys into table t,
+luaL_ref ensures the uniqueness of the key it returns.
+You can retrieve an object referred by reference r
+by calling lua_rawgeti(L, t, r).
+Function luaL_unref frees a reference and its associated object.
+
+
+
+If the object at the top of the stack is nil,
+luaL_ref returns the constant LUA_REFNIL.
+The constant LUA_NOREF is guaranteed to be different
+from any reference returned by luaL_ref.
+
+
+
+
+
+
luaL_Regtypedef struct luaL_Reg {
+ const char *name;
+ lua_CFunction func;
+} luaL_Reg;
+
+
+Type for arrays of functions to be registered by
+luaL_register.
+name is the function name and func is a pointer to
+the function.
+Any array of luaL_Reg must end with an sentinel entry
+in which both name and func are NULL.
+
+
+
+
+
+
luaL_register+[-(0|1), +1, m] +
void luaL_register (lua_State *L, + const char *libname, + const luaL_Reg *l);+ +
+Opens a library. + + +
+When called with libname equal to NULL,
+it simply registers all functions in the list l
+(see luaL_Reg) into the table on the top of the stack.
+
+
+
+When called with a non-null libname,
+luaL_register creates a new table t,
+sets it as the value of the global variable libname,
+sets it as the value of package.loaded[libname],
+and registers on it all functions in the list l.
+If there is a table in package.loaded[libname] or in
+variable libname,
+reuses this table instead of creating a new one.
+
+
+
+In any case the function leaves the table +on the top of the stack. + + + + + +
luaL_typename+[-0, +0, -] +
const char *luaL_typename (lua_State *L, int index);+ +
+Returns the name of the type of the value at the given index. + + + + + +
luaL_typerror+[-0, +0, v] +
int luaL_typerror (lua_State *L, int narg, const char *tname);+ +
+Generates an error with a message like the following: + +
+ location: bad argument narg to 'func' (tname expected, got rt) +
+where location is produced by luaL_where,
+func is the name of the current function,
+and rt is the type name of the actual argument.
+
+
+
+
+
+
luaL_unref+[-0, +0, -] +
void luaL_unref (lua_State *L, int t, int ref);+ +
+Releases reference ref from the table at index t
+(see luaL_ref).
+The entry is removed from the table,
+so that the referred object can be collected.
+The reference ref is also freed to be used again.
+
+
+
+If ref is LUA_NOREF or LUA_REFNIL,
+luaL_unref does nothing.
+
+
+
+
+
+
luaL_where+[-0, +1, m] +
void luaL_where (lua_State *L, int lvl);+ +
+Pushes onto the stack a string identifying the current position
+of the control at level lvl in the call stack.
+Typically this string has the following format:
+
+
+ chunkname:currentline: +
+Level 0 is the running function, +level 1 is the function that called the running function, +etc. + + +
+This function is used to build a prefix for error messages. + + + + + + + +
+The standard Lua libraries provide useful functions
+that are implemented directly through the C API.
+Some of these functions provide essential services to the language
+(e.g., type and getmetatable);
+others provide access to "outside" services (e.g., I/O);
+and others could be implemented in Lua itself,
+but are quite useful or have critical performance requirements that
+deserve an implementation in C (e.g., table.sort).
+
+
+
+All libraries are implemented through the official C API +and are provided as separate C modules. +Currently, Lua has the following standard libraries: + +
+Except for the basic and package libraries, +each library provides all its functions as fields of a global table +or as methods of its objects. + + +
+To have access to these libraries,
+the C host program should call the luaL_openlibs function,
+which opens all standard libraries.
+Alternatively,
+it can open them individually by calling
+luaopen_base (for the basic library),
+luaopen_package (for the package library),
+luaopen_string (for the string library),
+luaopen_table (for the table library),
+luaopen_math (for the mathematical library),
+luaopen_io (for the I/O library),
+luaopen_os (for the Operating System library),
+and luaopen_debug (for the debug library).
+These functions are declared in lualib.h
+and should not be called directly:
+you must call them like any other Lua C function,
+e.g., by using lua_call.
+
+
+
+
+The basic library provides some core functions to Lua. +If you do not include this library in your application, +you should check carefully whether you need to provide +implementations for some of its facilities. + + +
+
assert (v [, message])v is false (i.e., nil or false);
+otherwise, returns all its arguments.
+message is an error message;
+when absent, it defaults to "assertion failed!"
+
+
+
+
++
collectgarbage (opt [, arg])
+This function is a generic interface to the garbage collector.
+It performs different functions according to its first argument, opt:
+
+
arg
+(larger values mean more steps) in a non-specified way.
+If you want to control the step size
+you must experimentally tune the value of arg.
+Returns true if the step finished a collection cycle.
+arg/100 as the new value for the pause of
+the collector (see §2.10).
+arg/100 as the new value for the step multiplier of
+the collector (see §2.10).
++
dofile (filename)dofile executes the contents of the standard input (stdin).
+Returns all values returned by the chunk.
+In case of errors, dofile propagates the error
+to its caller (that is, dofile does not run in protected mode).
+
+
+
+
++
error (message [, level])message as the error message.
+Function error never returns.
+
+
+
+Usually, error adds some information about the error position
+at the beginning of the message.
+The level argument specifies how to get the error position.
+With level 1 (the default), the error position is where the
+error function was called.
+Level 2 points the error to where the function
+that called error was called; and so on.
+Passing a level 0 avoids the addition of error position information
+to the message.
+
+
+
+
+
+
_G_G._G = _G).
+Lua itself does not use this variable;
+changing its value does not affect any environment,
+nor vice-versa.
+(Use setfenv to change environments.)
+
+
+
+
++
getfenv ([f])f can be a Lua function or a number
+that specifies the function at that stack level:
+Level 1 is the function calling getfenv.
+If the given function is not a Lua function,
+or if f is 0,
+getfenv returns the global environment.
+The default for f is 1.
+
+
+
+
++
getmetatable (object)
+If object does not have a metatable, returns nil.
+Otherwise,
+if the object's metatable has a "__metatable" field,
+returns the associated value.
+Otherwise, returns the metatable of the given object.
+
+
+
+
+
+
ipairs (t)
+Returns three values: an iterator function, the table t, and 0,
+so that the construction
+
+
+ for i,v in ipairs(t) do body end +
+will iterate over the pairs (1,t[1]), (2,t[2]), ···,
+up to the first integer key absent from the table.
+
+
+
+
+
+
load (func [, chunkname])
+Loads a chunk using function func to get its pieces.
+Each call to func must return a string that concatenates
+with previous results.
+A return of nil (or no value) signals the end of the chunk.
+
+
+
+If there are no errors, +returns the compiled chunk as a function; +otherwise, returns nil plus the error message. +The environment of the returned function is the global environment. + + +
+chunkname is used as the chunk name for error messages
+and debug information.
+When absent,
+it defaults to "=(load)".
+
+
+
+
+
+
loadfile ([filename])
+Similar to load,
+but gets the chunk from file filename
+or from the standard input,
+if no file name is given.
+
+
+
+
+
+
loadstring (string [, chunkname])
+Similar to load,
+but gets the chunk from the given string.
+
+
+
+To load and run a given string, use the idiom + +
+ assert(loadstring(s))() ++ +
+When absent,
+chunkname defaults to the given string.
+
+
+
+
+
+
next (table [, index])
+Allows a program to traverse all fields of a table.
+Its first argument is a table and its second argument
+is an index in this table.
+next returns the next index of the table
+and its associated value.
+When called with nil as its second argument,
+next returns an initial index
+and its associated value.
+When called with the last index,
+or with nil in an empty table,
+next returns nil.
+If the second argument is absent, then it is interpreted as nil.
+In particular,
+you can use next(t) to check whether a table is empty.
+
+
+
+The order in which the indices are enumerated is not specified,
+even for numeric indices.
+(To traverse a table in numeric order,
+use a numerical for or the ipairs function.)
+
+
+
+The behavior of next is undefined if,
+during the traversal,
+you assign any value to a non-existent field in the table.
+You may however modify existing fields.
+In particular, you may clear existing fields.
+
+
+
+
+
+
pairs (t)
+Returns three values: the next function, the table t, and nil,
+so that the construction
+
+
+ for k,v in pairs(t) do body end +
+will iterate over all key–value pairs of table t.
+
+
+
+See function next for the caveats of modifying
+the table during its traversal.
+
+
+
+
+
+
pcall (f, arg1, ···)
+Calls function f with
+the given arguments in protected mode.
+This means that any error inside f is not propagated;
+instead, pcall catches the error
+and returns a status code.
+Its first result is the status code (a boolean),
+which is true if the call succeeds without errors.
+In such case, pcall also returns all results from the call,
+after this first result.
+In case of any error, pcall returns false plus the error message.
+
+
+
+
+
+
print (···)stdout,
+using the tostring function to convert them to strings.
+print is not intended for formatted output,
+but only as a quick way to show a value,
+typically for debugging.
+For formatted output, use string.format.
+
+
+
+
++
rawequal (v1, v2)v1 is equal to v2,
+without invoking any metamethod.
+Returns a boolean.
+
+
+
+
++
rawget (table, index)table[index],
+without invoking any metamethod.
+table must be a table;
+index may be any value.
+
+
+
+
++
rawset (table, index, value)table[index] to value,
+without invoking any metamethod.
+table must be a table,
+index any value different from nil,
+and value any Lua value.
+
+
+
+This function returns table.
+
+
+
+
+
+
select (index, ···)
+If index is a number,
+returns all arguments after argument number index.
+Otherwise, index must be the string "#",
+and select returns the total number of extra arguments it received.
+
+
+
+
+
+
setfenv (f, table)
+Sets the environment to be used by the given function.
+f can be a Lua function or a number
+that specifies the function at that stack level:
+Level 1 is the function calling setfenv.
+setfenv returns the given function.
+
+
+
+As a special case, when f is 0 setfenv changes
+the environment of the running thread.
+In this case, setfenv returns no values.
+
+
+
+
+
+
setmetatable (table, metatable)
+Sets the metatable for the given table.
+(You cannot change the metatable of other types from Lua, only from C.)
+If metatable is nil,
+removes the metatable of the given table.
+If the original metatable has a "__metatable" field,
+raises an error.
+
+
+
+This function returns table.
+
+
+
+
+
+
tonumber (e [, base])tonumber returns this number;
+otherwise, it returns nil.
+
+
+
+An optional argument specifies the base to interpret the numeral.
+The base may be any integer between 2 and 36, inclusive.
+In bases above 10, the letter 'A' (in either upper or lower case)
+represents 10, 'B' represents 11, and so forth,
+with 'Z' representing 35.
+In base 10 (the default), the number may have a decimal part,
+as well as an optional exponent part (see §2.1).
+In other bases, only unsigned integers are accepted.
+
+
+
+
+
+
tostring (e)string.format.
+
+
+
+If the metatable of e has a "__tostring" field,
+then tostring calls the corresponding value
+with e as argument,
+and uses the result of the call as its result.
+
+
+
+
+
+
type (v)nil" (a string, not the value nil),
+"number",
+"string",
+"boolean",
+"table",
+"function",
+"thread",
+and "userdata".
+
+
+
+
++
unpack (list [, i [, j]])+ return list[i], list[i+1], ···, list[j] +
+except that the above code can be written only for a fixed number
+of elements.
+By default, i is 1 and j is the length of the list,
+as defined by the length operator (see §2.5.5).
+
+
+
+
+
+
_VERSIONLua 5.1".
+
+
+
+
++
xpcall (f, err)
+This function is similar to pcall,
+except that you can set a new error handler.
+
+
+
+xpcall calls function f in protected mode,
+using err as the error handler.
+Any error inside f is not propagated;
+instead, xpcall catches the error,
+calls the err function with the original error object,
+and returns a status code.
+Its first result is the status code (a boolean),
+which is true if the call succeeds without errors.
+In this case, xpcall also returns all results from the call,
+after this first result.
+In case of any error,
+xpcall returns false plus the result from err.
+
+
+
+
+
+
+
+
+The operations related to coroutines comprise a sub-library of
+the basic library and come inside the table coroutine.
+See §2.11 for a general description of coroutines.
+
+
+
+
coroutine.create (f)
+Creates a new coroutine, with body f.
+f must be a Lua function.
+Returns this new coroutine,
+an object with type "thread".
+
+
+
+
+
+
coroutine.resume (co [, val1, ···])
+Starts or continues the execution of coroutine co.
+The first time you resume a coroutine,
+it starts running its body.
+The values val1, ··· are passed
+as the arguments to the body function.
+If the coroutine has yielded,
+resume restarts it;
+the values val1, ··· are passed
+as the results from the yield.
+
+
+
+If the coroutine runs without any errors,
+resume returns true plus any values passed to yield
+(if the coroutine yields) or any values returned by the body function
+(if the coroutine terminates).
+If there is any error,
+resume returns false plus the error message.
+
+
+
+
+
+
coroutine.running ()+Returns the running coroutine, +or nil when called by the main thread. + + + + +
+
coroutine.status (co)
+Returns the status of coroutine co, as a string:
+"running",
+if the coroutine is running (that is, it called status);
+"suspended", if the coroutine is suspended in a call to yield,
+or if it has not started running yet;
+"normal" if the coroutine is active but not running
+(that is, it has resumed another coroutine);
+and "dead" if the coroutine has finished its body function,
+or if it has stopped with an error.
+
+
+
+
+
+
coroutine.wrap (f)
+Creates a new coroutine, with body f.
+f must be a Lua function.
+Returns a function that resumes the coroutine each time it is called.
+Any arguments passed to the function behave as the
+extra arguments to resume.
+Returns the same values returned by resume,
+except the first boolean.
+In case of error, propagates the error.
+
+
+
+
+
+
coroutine.yield (···)
+Suspends the execution of the calling coroutine.
+The coroutine cannot be running a C function,
+a metamethod, or an iterator.
+Any arguments to yield are passed as extra results to resume.
+
+
+
+
+
+
+
+
+The package library provides basic
+facilities for loading and building modules in Lua.
+It exports two of its functions directly in the global environment:
+require and module.
+Everything else is exported in a table package.
+
+
+
+
module (name [, ···])
+Creates a module.
+If there is a table in package.loaded[name],
+this table is the module.
+Otherwise, if there is a global table t with the given name,
+this table is the module.
+Otherwise creates a new table t and
+sets it as the value of the global name and
+the value of package.loaded[name].
+This function also initializes t._NAME with the given name,
+t._M with the module (t itself),
+and t._PACKAGE with the package name
+(the full module name minus last component; see below).
+Finally, module sets t as the new environment
+of the current function and the new value of package.loaded[name],
+so that require returns t.
+
+
+
+If name is a compound name
+(that is, one with components separated by dots),
+module creates (or reuses, if they already exist)
+tables for each component.
+For instance, if name is a.b.c,
+then module stores the module table in field c of
+field b of global a.
+
+
+
+This function may receive optional options after +the module name, +where each option is a function to be applied over the module. + + + + +
+
require (modname)
+Loads the given module.
+The function starts by looking into the package.loaded table
+to determine whether modname is already loaded.
+If it is, then require returns the value stored
+at package.loaded[modname].
+Otherwise, it tries to find a loader for the module.
+
+
+
+To find a loader,
+require is guided by the package.loaders array.
+By changing this array,
+we can change how require looks for a module.
+The following explanation is based on the default configuration
+for package.loaders.
+
+
+
+First require queries package.preload[modname].
+If it has a value,
+this value (which should be a function) is the loader.
+Otherwise require searches for a Lua loader using the
+path stored in package.path.
+If that also fails, it searches for a C loader using the
+path stored in package.cpath.
+If that also fails,
+it tries an all-in-one loader (see package.loaders).
+
+
+
+Once a loader is found,
+require calls the loader with a single argument, modname.
+If the loader returns any value,
+require assigns the returned value to package.loaded[modname].
+If the loader returns no value and
+has not assigned any value to package.loaded[modname],
+then require assigns true to this entry.
+In any case, require returns the
+final value of package.loaded[modname].
+
+
+
+If there is any error loading or running the module,
+or if it cannot find any loader for the module,
+then require signals an error.
+
+
+
+
+
+
package.cpath
+The path used by require to search for a C loader.
+
+
+
+Lua initializes the C path package.cpath in the same way
+it initializes the Lua path package.path,
+using the environment variable LUA_CPATH
+or a default path defined in luaconf.h.
+
+
+
+
+
+ +
package.loaded
+A table used by require to control which
+modules are already loaded.
+When you require a module modname and
+package.loaded[modname] is not false,
+require simply returns the value stored there.
+
+
+
+
+
+
package.loaders
+A table used by require to control how to load modules.
+
+
+
+Each entry in this table is a searcher function.
+When looking for a module,
+require calls each of these searchers in ascending order,
+with the module name (the argument given to require) as its
+sole parameter.
+The function may return another function (the module loader)
+or a string explaining why it did not find that module
+(or nil if it has nothing to say).
+Lua initializes this table with four functions.
+
+
+
+The first searcher simply looks for a loader in the
+package.preload table.
+
+
+
+The second searcher looks for a loader as a Lua library,
+using the path stored at package.path.
+A path is a sequence of templates separated by semicolons.
+For each template,
+the searcher will change each interrogation
+mark in the template by filename,
+which is the module name with each dot replaced by a
+"directory separator" (such as "/" in Unix);
+then it will try to open the resulting file name.
+So, for instance, if the Lua path is the string
+
+
+ "./?.lua;./?.lc;/usr/local/?/init.lua" +
+the search for a Lua file for module foo
+will try to open the files
+./foo.lua, ./foo.lc, and
+/usr/local/foo/init.lua, in that order.
+
+
+
+The third searcher looks for a loader as a C library,
+using the path given by the variable package.cpath.
+For instance,
+if the C path is the string
+
+
+ "./?.so;./?.dll;/usr/local/?/init.so" +
+the searcher for module foo
+will try to open the files ./foo.so, ./foo.dll,
+and /usr/local/foo/init.so, in that order.
+Once it finds a C library,
+this searcher first uses a dynamic link facility to link the
+application with the library.
+Then it tries to find a C function inside the library to
+be used as the loader.
+The name of this C function is the string "luaopen_"
+concatenated with a copy of the module name where each dot
+is replaced by an underscore.
+Moreover, if the module name has a hyphen,
+its prefix up to (and including) the first hyphen is removed.
+For instance, if the module name is a.v1-b.c,
+the function name will be luaopen_b_c.
+
+
+
+The fourth searcher tries an all-in-one loader.
+It searches the C path for a library for
+the root name of the given module.
+For instance, when requiring a.b.c,
+it will search for a C library for a.
+If found, it looks into it for an open function for
+the submodule;
+in our example, that would be luaopen_a_b_c.
+With this facility, a package can pack several C submodules
+into one single library,
+with each submodule keeping its original open function.
+
+
+
+
+
+
package.loadlib (libname, funcname)
+Dynamically links the host program with the C library libname.
+Inside this library, looks for a function funcname
+and returns this function as a C function.
+(So, funcname must follow the protocol (see lua_CFunction)).
+
+
+
+This is a low-level function.
+It completely bypasses the package and module system.
+Unlike require,
+it does not perform any path searching and
+does not automatically adds extensions.
+libname must be the complete file name of the C library,
+including if necessary a path and extension.
+funcname must be the exact name exported by the C library
+(which may depend on the C compiler and linker used).
+
+
+
+This function is not supported by ANSI C.
+As such, it is only available on some platforms
+(Windows, Linux, Mac OS X, Solaris, BSD,
+plus other Unix systems that support the dlfcn standard).
+
+
+
+
+
+
package.path
+The path used by require to search for a Lua loader.
+
+
+
+At start-up, Lua initializes this variable with
+the value of the environment variable LUA_PATH or
+with a default path defined in luaconf.h,
+if the environment variable is not defined.
+Any ";;" in the value of the environment variable
+is replaced by the default path.
+
+
+
+
+
+
package.preload
+A table to store loaders for specific modules
+(see require).
+
+
+
+
+
+
package.seeall (module)
+Sets a metatable for module with
+its __index field referring to the global environment,
+so that this module inherits values
+from the global environment.
+To be used as an option to function module.
+
+
+
+
+
+
+
+
+This library provides generic functions for string manipulation, +such as finding and extracting substrings, and pattern matching. +When indexing a string in Lua, the first character is at position 1 +(not at 0, as in C). +Indices are allowed to be negative and are interpreted as indexing backwards, +from the end of the string. +Thus, the last character is at position -1, and so on. + + +
+The string library provides all its functions inside the table
+string.
+It also sets a metatable for strings
+where the __index field points to the string table.
+Therefore, you can use the string functions in object-oriented style.
+For instance, string.byte(s, i)
+can be written as s:byte(i).
+
+
+
+
string.byte (s [, i [, j]])s[i],
+s[i+1], ···, s[j].
+The default value for i is 1;
+the default value for j is i.
+
+
++Note that numerical codes are not necessarily portable across platforms. + + + + +
+
string.char (···)+Note that numerical codes are not necessarily portable across platforms. + + + + +
+
string.dump (function)
+Returns a string containing a binary representation of the given function,
+so that a later loadstring on this string returns
+a copy of the function.
+function must be a Lua function without upvalues.
+
+
+
+
+
+
string.find (s, pattern [, init [, plain]])pattern in the string s.
+If it finds a match, then find returns the indices of s
+where this occurrence starts and ends;
+otherwise, it returns nil.
+A third, optional numerical argument init specifies
+where to start the search;
+its default value is 1 and may be negative.
+A value of true as a fourth, optional argument plain
+turns off the pattern matching facilities,
+so the function does a plain "find substring" operation,
+with no characters in pattern being considered "magic".
+Note that if plain is given, then init must be given as well.
+
+
++If the pattern has captures, +then in a successful match +the captured values are also returned, +after the two indices. + + + + +
+
string.format (formatstring, ···)printf family of
+standard C functions.
+The only differences are that the options/modifiers
+*, l, L, n, p,
+and h are not supported
+and that there is an extra option, q.
+The q option formats a string in a form suitable to be safely read
+back by the Lua interpreter:
+the string is written between double quotes,
+and all double quotes, newlines, embedded zeros,
+and backslashes in the string
+are correctly escaped when written.
+For instance, the call
+
+
+ string.format('%q', 'a string with "quotes" and \n new line')
++will produce the string: + +
+ "a string with \"quotes\" and \ + new line" ++ +
+The options c, d, E, e, f,
+g, G, i, o, u, X, and x all
+expect a number as argument,
+whereas q and s expect a string.
+
+
+
+This function does not accept string values
+containing embedded zeros,
+except as arguments to the q option.
+
+
+
+
+
+
string.gmatch (s, pattern)pattern over string s.
+If pattern specifies no captures,
+then the whole match is produced in each call.
+
+
++As an example, the following loop + +
+ s = "hello world from Lua" + for w in string.gmatch(s, "%a+") do + print(w) + end +
+will iterate over all the words from string s,
+printing one per line.
+The next example collects all pairs key=value from the
+given string into a table:
+
+
+ t = {}
+ s = "from=world, to=Lua"
+ for k, v in string.gmatch(s, "(%w+)=(%w+)") do
+ t[k] = v
+ end
+
+
+
+For this function, a '^' at the start of a pattern does not
+work as an anchor, as this would prevent the iteration.
+
+
+
+
+
+
string.gsub (s, pattern, repl [, n])s
+in which all (or the first n, if given)
+occurrences of the pattern have been
+replaced by a replacement string specified by repl,
+which may be a string, a table, or a function.
+gsub also returns, as its second value,
+the total number of matches that occurred.
+
+
+
+If repl is a string, then its value is used for replacement.
+The character % works as an escape character:
+any sequence in repl of the form %n,
+with n between 1 and 9,
+stands for the value of the n-th captured substring (see below).
+The sequence %0 stands for the whole match.
+The sequence %% stands for a single %.
+
+
+
+If repl is a table, then the table is queried for every match,
+using the first capture as the key;
+if the pattern specifies no captures,
+then the whole match is used as the key.
+
+
+
+If repl is a function, then this function is called every time a
+match occurs, with all captured substrings passed as arguments,
+in order;
+if the pattern specifies no captures,
+then the whole match is passed as a sole argument.
+
+
+
+If the value returned by the table query or by the function call +is a string or a number, +then it is used as the replacement string; +otherwise, if it is false or nil, +then there is no replacement +(that is, the original match is kept in the string). + + +
+Here are some examples: + +
+ x = string.gsub("hello world", "(%w+)", "%1 %1")
+ --> x="hello hello world world"
+
+ x = string.gsub("hello world", "%w+", "%0 %0", 1)
+ --> x="hello hello world"
+
+ x = string.gsub("hello world from Lua", "(%w+)%s*(%w+)", "%2 %1")
+ --> x="world hello Lua from"
+
+ x = string.gsub("home = $HOME, user = $USER", "%$(%w+)", os.getenv)
+ --> x="home = /home/roberto, user = roberto"
+
+ x = string.gsub("4+5 = $return 4+5$", "%$(.-)%$", function (s)
+ return loadstring(s)()
+ end)
+ --> x="4+5 = 9"
+
+ local t = {name="lua", version="5.1"}
+ x = string.gsub("$name-$version.tar.gz", "%$(%w+)", t)
+ --> x="lua-5.1.tar.gz"
+
+
+
+
++
string.len (s)"" has length 0.
+Embedded zeros are counted,
+so "a\000bc\000" has length 5.
+
+
+
+
++
string.lower (s)+
string.match (s, pattern [, init])pattern in the string s.
+If it finds one, then match returns
+the captures from the pattern;
+otherwise it returns nil.
+If pattern specifies no captures,
+then the whole match is returned.
+A third, optional numerical argument init specifies
+where to start the search;
+its default value is 1 and may be negative.
+
+
+
+
++
string.rep (s, n)n copies of
+the string s.
+
+
+
+
++
string.reverse (s)s reversed.
+
+
+
+
++
string.sub (s, i [, j])s that
+starts at i and continues until j;
+i and j may be negative.
+If j is absent, then it is assumed to be equal to -1
+(which is the same as the string length).
+In particular,
+the call string.sub(s,1,j) returns a prefix of s
+with length j,
+and string.sub(s, -i) returns a suffix of s
+with length i.
+
+
+
+
++
string.upper (s)+A character class is used to represent a set of characters. +The following combinations are allowed in describing a character class: + +
^$()%.[]*+-?)
+represents the character x itself.
+.: (a dot) represents all characters.%a: represents all letters.%c: represents all control characters.%d: represents all digits.%l: represents all lowercase letters.%p: represents all punctuation characters.%s: represents all space characters.%u: represents all uppercase letters.%w: represents all alphanumeric characters.%x: represents all hexadecimal digits.%z: represents the character with representation 0.%x: (where x is any non-alphanumeric character)
+represents the character x.
+This is the standard way to escape the magic characters.
+Any punctuation character (even the non magic)
+can be preceded by a '%'
+when used to represent itself in a pattern.
+[set]:
+represents the class which is the union of all
+characters in set.
+A range of characters may be specified by
+separating the end characters of the range with a '-'.
+All classes %x described above may also be used as
+components in set.
+All other characters in set represent themselves.
+For example, [%w_] (or [_%w])
+represents all alphanumeric characters plus the underscore,
+[0-7] represents the octal digits,
+and [0-7%l%-] represents the octal digits plus
+the lowercase letters plus the '-' character.
+
+
+
+The interaction between ranges and classes is not defined.
+Therefore, patterns like [%a-z] or [a-%%]
+have no meaning.
+
[^set]:
+represents the complement of set,
+where set is interpreted as above.
+
+For all classes represented by single letters (%a, %c, etc.),
+the corresponding uppercase letter represents the complement of the class.
+For instance, %S represents all non-space characters.
+
+
+
+The definitions of letter, space, and other character groups
+depend on the current locale.
+In particular, the class [a-z] may not be equivalent to %l.
+
+
+
+
+
+
+A pattern item may be + +
*',
+which matches 0 or more repetitions of characters in the class.
+These repetition items will always match the longest possible sequence;
++',
+which matches 1 or more repetitions of characters in the class.
+These repetition items will always match the longest possible sequence;
+-',
+which also matches 0 or more repetitions of characters in the class.
+Unlike '*',
+these repetition items will always match the shortest possible sequence;
+?',
+which matches 0 or 1 occurrence of a character in the class;
+%n, for n between 1 and 9;
+such item matches a substring equal to the n-th captured string
+(see below);
+%bxy, where x and y are two distinct characters;
+such item matches strings that start with x, end with y,
+and where the x and y are balanced.
+This means that, if one reads the string from left to right,
+counting +1 for an x and -1 for a y,
+the ending y is the first y where the count reaches 0.
+For instance, the item %b() matches expressions with
+balanced parentheses.
+
+A pattern is a sequence of pattern items.
+A '^' at the beginning of a pattern anchors the match at the
+beginning of the subject string.
+A '$' at the end of a pattern anchors the match at the
+end of the subject string.
+At other positions,
+'^' and '$' have no special meaning and represent themselves.
+
+
+
+
+
+
+A pattern may contain sub-patterns enclosed in parentheses;
+they describe captures.
+When a match succeeds, the substrings of the subject string
+that match captures are stored (captured) for future use.
+Captures are numbered according to their left parentheses.
+For instance, in the pattern "(a*(.)%w(%s*))",
+the part of the string matching "a*(.)%w(%s*)" is
+stored as the first capture (and therefore has number 1);
+the character matching "." is captured with number 2,
+and the part matching "%s*" has number 3.
+
+
+
+As a special case, the empty capture () captures
+the current string position (a number).
+For instance, if we apply the pattern "()aa()" on the
+string "flaaap", there will be two captures: 3 and 5.
+
+
+
+A pattern cannot contain embedded zeros. Use %z instead.
+
+
+
+
+
+
+
+
+
+
+
+
+This library provides generic functions for table manipulation.
+It provides all its functions inside the table table.
+
+
+
+Most functions in the table library assume that the table +represents an array or a list. +For these functions, when we talk about the "length" of a table +we mean the result of the length operator. + + +
+
table.concat (table [, sep [, i [, j]]])table[i]..sep..table[i+1] ··· sep..table[j].
+The default value for sep is the empty string,
+the default for i is 1,
+and the default for j is the length of the table.
+If i is greater than j, returns the empty string.
+
+
+
+
++
table.insert (table, [pos,] value)
+Inserts element value at position pos in table,
+shifting up other elements to open space, if necessary.
+The default value for pos is n+1,
+where n is the length of the table (see §2.5.5),
+so that a call table.insert(t,x) inserts x at the end
+of table t.
+
+
+
+
+
+
table.maxn (table)+Returns the largest positive numerical index of the given table, +or zero if the table has no positive numerical indices. +(To do its job this function does a linear traversal of +the whole table.) + + + + +
+
table.remove (table [, pos])
+Removes from table the element at position pos,
+shifting down other elements to close the space, if necessary.
+Returns the value of the removed element.
+The default value for pos is n,
+where n is the length of the table,
+so that a call table.remove(t) removes the last element
+of table t.
+
+
+
+
+
+
table.sort (table [, comp])table[1] to table[n],
+where n is the length of the table.
+If comp is given,
+then it must be a function that receives two table elements,
+and returns true
+when the first is less than the second
+(so that not comp(a[i+1],a[i]) will be true after the sort).
+If comp is not given,
+then the standard Lua operator < is used instead.
+
+
++The sort algorithm is not stable; +that is, elements considered equal by the given order +may have their relative positions changed by the sort. + + + + + + + +
+This library is an interface to the standard C math library.
+It provides all its functions inside the table math.
+
+
+
+
math.abs (x)
+Returns the absolute value of x.
+
+
+
+
+
+
math.acos (x)
+Returns the arc cosine of x (in radians).
+
+
+
+
+
+
math.asin (x)
+Returns the arc sine of x (in radians).
+
+
+
+
+
+
math.atan (x)
+Returns the arc tangent of x (in radians).
+
+
+
+
+
+
math.atan2 (y, x)
+Returns the arc tangent of y/x (in radians),
+but uses the signs of both parameters to find the
+quadrant of the result.
+(It also handles correctly the case of x being zero.)
+
+
+
+
+
+
math.ceil (x)
+Returns the smallest integer larger than or equal to x.
+
+
+
+
+
+
math.cos (x)
+Returns the cosine of x (assumed to be in radians).
+
+
+
+
+
+
math.cosh (x)
+Returns the hyperbolic cosine of x.
+
+
+
+
+
+
math.deg (x)
+Returns the angle x (given in radians) in degrees.
+
+
+
+
+
+
math.exp (x)+Returns the value ex. + + + + +
+
math.floor (x)
+Returns the largest integer smaller than or equal to x.
+
+
+
+
+
+
math.fmod (x, y)
+Returns the remainder of the division of x by y.
+
+
+
+
+
+
math.frexp (x)
+Returns m and e such that x = m2e,
+e is an integer and the absolute value of m is
+in the range [0.5, 1)
+(or zero when x is zero).
+
+
+
+
+
+
math.huge
+The value HUGE_VAL,
+a value larger than or equal to any other numerical value.
+
+
+
+
+
+
math.ldexp (m, e)
+Returns m2e (e should be an integer).
+
+
+
+
+
+
math.log (x)
+Returns the natural logarithm of x.
+
+
+
+
+
+
math.log10 (x)
+Returns the base-10 logarithm of x.
+
+
+
+
+
+
math.max (x, ···)+Returns the maximum value among its arguments. + + + + +
+
math.min (x, ···)+Returns the minimum value among its arguments. + + + + +
+
math.modf (x)
+Returns two numbers,
+the integral part of x and the fractional part of x.
+
+
+
+
+
+
math.pi+The value of pi. + + + + +
+
math.pow (x, y)
+Returns xy.
+(You can also use the expression x^y to compute this value.)
+
+
+
+
+
+
math.rad (x)
+Returns the angle x (given in degrees) in radians.
+
+
+
+
+
+
math.random ([m [, n]])
+This function is an interface to the simple
+pseudo-random generator function rand provided by ANSI C.
+(No guarantees can be given for its statistical properties.)
+
+
+
+When called without arguments,
+returns a uniform pseudo-random real number
+in the range [0,1).
+When called with an integer number m,
+math.random returns
+a uniform pseudo-random integer in the range [1, m].
+When called with two integer numbers m and n,
+math.random returns a uniform pseudo-random
+integer in the range [m, n].
+
+
+
+
+
+
math.randomseed (x)
+Sets x as the "seed"
+for the pseudo-random generator:
+equal seeds produce equal sequences of numbers.
+
+
+
+
+
+
math.sin (x)
+Returns the sine of x (assumed to be in radians).
+
+
+
+
+
+
math.sinh (x)
+Returns the hyperbolic sine of x.
+
+
+
+
+
+
math.sqrt (x)
+Returns the square root of x.
+(You can also use the expression x^0.5 to compute this value.)
+
+
+
+
+
+
math.tan (x)
+Returns the tangent of x (assumed to be in radians).
+
+
+
+
+
+
math.tanh (x)
+Returns the hyperbolic tangent of x.
+
+
+
+
+
+
+
+
+The I/O library provides two different styles for file manipulation. +The first one uses implicit file descriptors; +that is, there are operations to set a default input file and a +default output file, +and all input/output operations are over these default files. +The second style uses explicit file descriptors. + + +
+When using implicit file descriptors,
+all operations are supplied by table io.
+When using explicit file descriptors,
+the operation io.open returns a file descriptor
+and then all operations are supplied as methods of the file descriptor.
+
+
+
+The table io also provides
+three predefined file descriptors with their usual meanings from C:
+io.stdin, io.stdout, and io.stderr.
+The I/O library never closes these files.
+
+
+
+Unless otherwise stated, +all I/O functions return nil on failure +(plus an error message as a second result and +a system-dependent error code as a third result) +and some value different from nil on success. + + +
+
io.close ([file])
+Equivalent to file:close().
+Without a file, closes the default output file.
+
+
+
+
+
+
io.flush ()
+Equivalent to file:flush over the default output file.
+
+
+
+
+
+
io.input ([file])+When called with a file name, it opens the named file (in text mode), +and sets its handle as the default input file. +When called with a file handle, +it simply sets this file handle as the default input file. +When called without parameters, +it returns the current default input file. + + +
+In case of errors this function raises the error, +instead of returning an error code. + + + + +
+
io.lines ([filename])+Opens the given file name in read mode +and returns an iterator function that, +each time it is called, +returns a new line from the file. +Therefore, the construction + +
+ for line in io.lines(filename) do body end +
+will iterate over all lines of the file. +When the iterator function detects the end of file, +it returns nil (to finish the loop) and automatically closes the file. + + +
+The call io.lines() (with no file name) is equivalent
+to io.input():lines();
+that is, it iterates over the lines of the default input file.
+In this case it does not close the file when the loop ends.
+
+
+
+
+
+
io.open (filename [, mode])
+This function opens a file,
+in the mode specified in the string mode.
+It returns a new file handle,
+or, in case of errors, nil plus an error message.
+
+
+
+The mode string can be any of the following:
+
+
+The mode string may also have a 'b' at the end,
+which is needed in some systems to open the file in binary mode.
+This string is exactly what is used in the
+standard C function fopen.
+
+
+
+
+
+
io.output ([file])
+Similar to io.input, but operates over the default output file.
+
+
+
+
+
+
io.popen (prog [, mode])
+Starts program prog in a separated process and returns
+a file handle that you can use to read data from this program
+(if mode is "r", the default)
+or to write data to this program
+(if mode is "w").
+
+
+
+This function is system dependent and is not available +on all platforms. + + + + +
+
io.read (···)
+Equivalent to io.input():read.
+
+
+
+
+
+
io.tmpfile ()+Returns a handle for a temporary file. +This file is opened in update mode +and it is automatically removed when the program ends. + + + + +
+
io.type (obj)
+Checks whether obj is a valid file handle.
+Returns the string "file" if obj is an open file handle,
+"closed file" if obj is a closed file handle,
+or nil if obj is not a file handle.
+
+
+
+
+
+
io.write (···)
+Equivalent to io.output():write.
+
+
+
+
+
+
file:close ()
+Closes file.
+Note that files are automatically closed when
+their handles are garbage collected,
+but that takes an unpredictable amount of time to happen.
+
+
+
+
+
+
file:flush ()
+Saves any written data to file.
+
+
+
+
+
+
file:lines ()+Returns an iterator function that, +each time it is called, +returns a new line from the file. +Therefore, the construction + +
+ for line in file:lines() do body end +
+will iterate over all lines of the file.
+(Unlike io.lines, this function does not close the file
+when the loop ends.)
+
+
+
+
+
+
file:read (···)
+Reads the file file,
+according to the given formats, which specify what to read.
+For each format,
+the function returns a string (or a number) with the characters read,
+or nil if it cannot read data with the specified format.
+When called without formats,
+it uses a default format that reads the entire next line
+(see below).
+
+
+
+The available formats are + +
+
file:seek ([whence] [, offset])
+Sets and gets the file position,
+measured from the beginning of the file,
+to the position given by offset plus a base
+specified by the string whence, as follows:
+
+
+In case of success, function seek returns the final file position,
+measured in bytes from the beginning of the file.
+If this function fails, it returns nil,
+plus a string describing the error.
+
+
+
+The default value for whence is "cur",
+and for offset is 0.
+Therefore, the call file:seek() returns the current
+file position, without changing it;
+the call file:seek("set") sets the position to the
+beginning of the file (and returns 0);
+and the call file:seek("end") sets the position to the
+end of the file, and returns its size.
+
+
+
+
+
+
file:setvbuf (mode [, size])+Sets the buffering mode for an output file. +There are three available modes: + +
flush the file
+(see io.flush)).
+
+For the last two cases, size
+specifies the size of the buffer, in bytes.
+The default is an appropriate size.
+
+
+
+
+
+
file:write (···)
+Writes the value of each of its arguments to
+the file.
+The arguments must be strings or numbers.
+To write other values,
+use tostring or string.format before write.
+
+
+
+
+
+
+
+
+This library is implemented through table os.
+
+
+
+
os.clock ()+Returns an approximation of the amount in seconds of CPU time +used by the program. + + + + +
+
os.date ([format [, time]])
+Returns a string or a table containing date and time,
+formatted according to the given string format.
+
+
+
+If the time argument is present,
+this is the time to be formatted
+(see the os.time function for a description of this value).
+Otherwise, date formats the current time.
+
+
+
+If format starts with '!',
+then the date is formatted in Coordinated Universal Time.
+After this optional character,
+if format is the string "*t",
+then date returns a table with the following fields:
+year (four digits), month (1--12), day (1--31),
+hour (0--23), min (0--59), sec (0--61),
+wday (weekday, Sunday is 1),
+yday (day of the year),
+and isdst (daylight saving flag, a boolean).
+
+
+
+If format is not "*t",
+then date returns the date as a string,
+formatted according to the same rules as the C function strftime.
+
+
+
+When called without arguments,
+date returns a reasonable date and time representation that depends on
+the host system and on the current locale
+(that is, os.date() is equivalent to os.date("%c")).
+
+
+
+
+
+
os.difftime (t2, t1)
+Returns the number of seconds from time t1 to time t2.
+In POSIX, Windows, and some other systems,
+this value is exactly t2-t1.
+
+
+
+
+
+
os.execute ([command])
+This function is equivalent to the C function system.
+It passes command to be executed by an operating system shell.
+It returns a status code, which is system-dependent.
+If command is absent, then it returns nonzero if a shell is available
+and zero otherwise.
+
+
+
+
+
+
os.exit ([code])
+Calls the C function exit,
+with an optional code,
+to terminate the host program.
+The default value for code is the success code.
+
+
+
+
+
+
os.getenv (varname)
+Returns the value of the process environment variable varname,
+or nil if the variable is not defined.
+
+
+
+
+
+
os.remove (filename)+Deletes the file or directory with the given name. +Directories must be empty to be removed. +If this function fails, it returns nil, +plus a string describing the error. + + + + +
+
os.rename (oldname, newname)
+Renames file or directory named oldname to newname.
+If this function fails, it returns nil,
+plus a string describing the error.
+
+
+
+
+
+
os.setlocale (locale [, category])
+Sets the current locale of the program.
+locale is a string specifying a locale;
+category is an optional string describing which category to change:
+"all", "collate", "ctype",
+"monetary", "numeric", or "time";
+the default category is "all".
+The function returns the name of the new locale,
+or nil if the request cannot be honored.
+
+
+
+If locale is the empty string,
+the current locale is set to an implementation-defined native locale.
+If locale is the string "C",
+the current locale is set to the standard C locale.
+
+
+
+When called with nil as the first argument, +this function only returns the name of the current locale +for the given category. + + + + +
+
os.time ([table])
+Returns the current time when called without arguments,
+or a time representing the date and time specified by the given table.
+This table must have fields year, month, and day,
+and may have fields hour, min, sec, and isdst
+(for a description of these fields, see the os.date function).
+
+
+
+The returned value is a number, whose meaning depends on your system.
+In POSIX, Windows, and some other systems, this number counts the number
+of seconds since some given start time (the "epoch").
+In other systems, the meaning is not specified,
+and the number returned by time can be used only as an argument to
+date and difftime.
+
+
+
+
+
+
os.tmpname ()+Returns a string with a file name that can +be used for a temporary file. +The file must be explicitly opened before its use +and explicitly removed when no longer needed. + + + + + + + +
+This library provides +the functionality of the debug interface to Lua programs. +You should exert care when using this library. +The functions provided here should be used exclusively for debugging +and similar tasks, such as profiling. +Please resist the temptation to use them as a +usual programming tool: +they can be very slow. +Moreover, several of these functions +violate some assumptions about Lua code +(e.g., that variables local to a function +cannot be accessed from outside or +that userdata metatables cannot be changed by Lua code) +and therefore can compromise otherwise secure code. + + +
+All functions in this library are provided
+inside the debug table.
+All functions that operate over a thread
+have an optional first argument which is the
+thread to operate over.
+The default is always the current thread.
+
+
+
+
debug.debug ()
+Enters an interactive mode with the user,
+running each string that the user enters.
+Using simple commands and other debug facilities,
+the user can inspect global and local variables,
+change their values, evaluate expressions, and so on.
+A line containing only the word cont finishes this function,
+so that the caller continues its execution.
+
+
+
+Note that commands for debug.debug are not lexically nested
+within any function, and so have no direct access to local variables.
+
+
+
+
+
+
debug.getfenv (o)o.
+
+
+
+
++
debug.gethook ([thread])
+Returns the current hook settings of the thread, as three values:
+the current hook function, the current hook mask,
+and the current hook count
+(as set by the debug.sethook function).
+
+
+
+
+
+
debug.getinfo ([thread,] function [, what])
+Returns a table with information about a function.
+You can give the function directly,
+or you can give a number as the value of function,
+which means the function running at level function of the call stack
+of the given thread:
+level 0 is the current function (getinfo itself);
+level 1 is the function that called getinfo;
+and so on.
+If function is a number larger than the number of active functions,
+then getinfo returns nil.
+
+
+
+The returned table may contain all the fields returned by lua_getinfo,
+with the string what describing which fields to fill in.
+The default for what is to get all information available,
+except the table of valid lines.
+If present,
+the option 'f'
+adds a field named func with the function itself.
+If present,
+the option 'L'
+adds a field named activelines with the table of
+valid lines.
+
+
+
+For instance, the expression debug.getinfo(1,"n").name returns
+a table with a name for the current function,
+if a reasonable name can be found,
+and the expression debug.getinfo(print)
+returns a table with all available information
+about the print function.
+
+
+
+
+
+
debug.getlocal ([thread,] level, local)
+This function returns the name and the value of the local variable
+with index local of the function at level level of the stack.
+(The first parameter or local variable has index 1, and so on,
+until the last active local variable.)
+The function returns nil if there is no local
+variable with the given index,
+and raises an error when called with a level out of range.
+(You can call debug.getinfo to check whether the level is valid.)
+
+
+
+Variable names starting with '(' (open parentheses)
+represent internal variables
+(loop control variables, temporaries, and C function locals).
+
+
+
+
+
+
debug.getmetatable (object)
+Returns the metatable of the given object
+or nil if it does not have a metatable.
+
+
+
+
+
+
debug.getregistry ()+Returns the registry table (see §3.5). + + + + +
+
debug.getupvalue (func, up)
+This function returns the name and the value of the upvalue
+with index up of the function func.
+The function returns nil if there is no upvalue with the given index.
+
+
+
+
+
+
debug.setfenv (object, table)
+Sets the environment of the given object to the given table.
+Returns object.
+
+
+
+
+
+
debug.sethook ([thread,] hook, mask [, count])
+Sets the given function as a hook.
+The string mask and the number count describe
+when the hook will be called.
+The string mask may have the following characters,
+with the given meaning:
+
+
"c": the hook is called every time Lua calls a function;"r": the hook is called every time Lua returns from a function;"l": the hook is called every time Lua enters a new line of code.
+With a count different from zero,
+the hook is called after every count instructions.
+
+
+
+When called without arguments,
+debug.sethook turns off the hook.
+
+
+
+When the hook is called, its first parameter is a string
+describing the event that has triggered its call:
+"call", "return" (or "tail return"),
+"line", and "count".
+For line events,
+the hook also gets the new line number as its second parameter.
+Inside a hook,
+you can call getinfo with level 2 to get more information about
+the running function
+(level 0 is the getinfo function,
+and level 1 is the hook function),
+unless the event is "tail return".
+In this case, Lua is only simulating the return,
+and a call to getinfo will return invalid data.
+
+
+
+
+
+
debug.setlocal ([thread,] level, local, value)
+This function assigns the value value to the local variable
+with index local of the function at level level of the stack.
+The function returns nil if there is no local
+variable with the given index,
+and raises an error when called with a level out of range.
+(You can call getinfo to check whether the level is valid.)
+Otherwise, it returns the name of the local variable.
+
+
+
+
+
+
debug.setmetatable (object, table)
+Sets the metatable for the given object to the given table
+(which can be nil).
+
+
+
+
+
+
debug.setupvalue (func, up, value)
+This function assigns the value value to the upvalue
+with index up of the function func.
+The function returns nil if there is no upvalue
+with the given index.
+Otherwise, it returns the name of the upvalue.
+
+
+
+
+
+
debug.traceback ([thread,] [message] [, level])
+Returns a string with a traceback of the call stack.
+An optional message string is appended
+at the beginning of the traceback.
+An optional level number tells at which level
+to start the traceback
+(default is 1, the function calling traceback).
+
+
+
+
+
+
+
+
+Although Lua has been designed as an extension language,
+to be embedded in a host C program,
+it is also frequently used as a stand-alone language.
+An interpreter for Lua as a stand-alone language,
+called simply lua,
+is provided with the standard distribution.
+The stand-alone interpreter includes
+all standard libraries, including the debug library.
+Its usage is:
+
+
+ lua [options] [script [args]] +
+The options are: + +
-e stat: executes string stat;-l mod: "requires" mod;-i: enters interactive mode after running script;-v: prints version information;--: stops handling options;-: executes stdin as a file and stops handling options.
+After handling its options, lua runs the given script,
+passing to it the given args as string arguments.
+When called without arguments,
+lua behaves as lua -v -i
+when the standard input (stdin) is a terminal,
+and as lua - otherwise.
+
+
+
+Before running any argument,
+the interpreter checks for an environment variable LUA_INIT.
+If its format is @filename,
+then lua executes the file.
+Otherwise, lua executes the string itself.
+
+
+
+All options are handled in order, except -i.
+For instance, an invocation like
+
+
+ $ lua -e'a=1' -e 'print(a)' script.lua +
+will first set a to 1, then print the value of a (which is '1'),
+and finally run the file script.lua with no arguments.
+(Here $ is the shell prompt. Your prompt may be different.)
+
+
+
+Before starting to run the script,
+lua collects all arguments in the command line
+in a global table called arg.
+The script name is stored at index 0,
+the first argument after the script name goes to index 1,
+and so on.
+Any arguments before the script name
+(that is, the interpreter name plus the options)
+go to negative indices.
+For instance, in the call
+
+
+ $ lua -la b.lua t1 t2 +
+the interpreter first runs the file a.lua,
+then creates a table
+
+
+ arg = { [-2] = "lua", [-1] = "-la",
+ [0] = "b.lua",
+ [1] = "t1", [2] = "t2" }
+
+and finally runs the file b.lua.
+The script is called with arg[1], arg[2], ···
+as arguments;
+it can also access these arguments with the vararg expression '...'.
+
+
+
+In interactive mode, +if you write an incomplete statement, +the interpreter waits for its completion +by issuing a different prompt. + + +
+If the global variable _PROMPT contains a string,
+then its value is used as the prompt.
+Similarly, if the global variable _PROMPT2 contains a string,
+its value is used as the secondary prompt
+(issued during incomplete statements).
+Therefore, both prompts can be changed directly on the command line
+or in any Lua programs by assigning to _PROMPT.
+See the next example:
+
+
+ $ lua -e"_PROMPT='myprompt> '" -i +
+(The outer pair of quotes is for the shell,
+the inner pair is for Lua.)
+Note the use of -i to enter interactive mode;
+otherwise,
+the program would just end silently
+right after the assignment to _PROMPT.
+
+
+
+To allow the use of Lua as a
+script interpreter in Unix systems,
+the stand-alone interpreter skips
+the first line of a chunk if it starts with #.
+Therefore, Lua scripts can be made into executable programs
+by using chmod +x and the #! form,
+as in
+
+
+ #!/usr/local/bin/lua +
+(Of course,
+the location of the Lua interpreter may be different in your machine.
+If lua is in your PATH,
+then
+
+
+ #!/usr/bin/env lua +
+is a more portable solution.) + + + +
+Here we list the incompatibilities that you may find when moving a program
+from Lua 5.0 to Lua 5.1.
+You can avoid most of the incompatibilities compiling Lua with
+appropriate options (see file luaconf.h).
+However,
+all these compatibility options will be removed in the next version of Lua.
+
+
+
+
arg with a
+table with the extra arguments to the vararg expression.
+(See compile-time option LUA_COMPAT_VARARG in luaconf.h.)
+[[string]])
+does not allow nesting.
+You can use the new syntax ([=[string]=]) in these cases.
+(See compile-time option LUA_COMPAT_LSTR in luaconf.h.)
+string.gfind was renamed string.gmatch.
+(See compile-time option LUA_COMPAT_GFIND in luaconf.h.)
+string.gsub is called with a function as its
+third argument,
+whenever this function returns nil or false the
+replacement string is the whole match,
+instead of the empty string.
+table.setn was deprecated.
+Function table.getn corresponds
+to the new length operator (#);
+use the operator instead of the function.
+(See compile-time option LUA_COMPAT_GETN in luaconf.h.)
+loadlib was renamed package.loadlib.
+(See compile-time option LUA_COMPAT_LOADLIB in luaconf.h.)
+math.mod was renamed math.fmod.
+(See compile-time option LUA_COMPAT_MOD in luaconf.h.)
+table.foreach and table.foreachi are deprecated.
+You can use a for loop with pairs or ipairs instead.
+require due to
+the new module system.
+However, the new behavior is mostly compatible with the old,
+but require gets the path from package.path instead
+of from LUA_PATH.
+collectgarbage has different arguments.
+Function gcinfo is deprecated;
+use collectgarbage("count") instead.
+luaopen_* functions (to open libraries)
+cannot be called directly,
+like a regular C function.
+They must be called through Lua,
+like a Lua function.
+lua_open was replaced by lua_newstate to
+allow the user to set a memory-allocation function.
+You can use luaL_newstate from the standard library to
+create a state with a standard allocation function
+(based on realloc).
+luaL_getn and luaL_setn
+(from the auxiliary library) are deprecated.
+Use lua_objlen instead of luaL_getn
+and nothing instead of luaL_setn.
+luaL_openlib was replaced by luaL_register.
+luaL_checkudata now throws an error when the given value
+is not a userdata of the expected type.
+(In Lua 5.0 it returned NULL.)
++Here is the complete syntax of Lua in extended BNF. +(It does not describe operator precedences.) + + + + +
+
+ chunk ::= {stat [`;´]} [laststat [`;´]]
+
+ block ::= chunk
+
+ stat ::= varlist `=´ explist |
+ functioncall |
+ do block end |
+ while exp do block end |
+ repeat block until exp |
+ if exp then block {elseif exp then block} [else block] end |
+ for Name `=´ exp `,´ exp [`,´ exp] do block end |
+ for namelist in explist do block end |
+ function funcname funcbody |
+ local function Name funcbody |
+ local namelist [`=´ explist]
+
+ laststat ::= return [explist] | break
+
+ funcname ::= Name {`.´ Name} [`:´ Name]
+
+ varlist ::= var {`,´ var}
+
+ var ::= Name | prefixexp `[´ exp `]´ | prefixexp `.´ Name
+
+ namelist ::= Name {`,´ Name}
+
+ explist ::= {exp `,´} exp
+
+ exp ::= nil | false | true | Number | String | `...´ | function |
+ prefixexp | tableconstructor | exp binop exp | unop exp
+
+ prefixexp ::= var | functioncall | `(´ exp `)´
+
+ functioncall ::= prefixexp args | prefixexp `:´ Name args
+
+ args ::= `(´ [explist] `)´ | tableconstructor | String
+
+ function ::= function funcbody
+
+ funcbody ::= `(´ [parlist] `)´ block end
+
+ parlist ::= namelist [`,´ `...´] | `...´
+
+ tableconstructor ::= `{´ [fieldlist] `}´
+
+ fieldlist ::= field {fieldsep field} [fieldsep]
+
+ field ::= `[´ exp `]´ `=´ exp | Name `=´ exp | exp
+
+ fieldsep ::= `,´ | `;´
+
+ binop ::= `+´ | `-´ | `*´ | `/´ | `^´ | `%´ | `..´ |
+ `<´ | `<=´ | `>´ | `>=´ | `==´ | `~=´ |
+ and | or
+
+ unop ::= `-´ | not | `#´
+
+
+
++ + + + + + + +
+Documentation
++ +
lsizenode))
+
+
+#define luaO_nilobject (&luaO_nilobject_)
+
+LUAI_DATA const TValue luaO_nilobject_;
+
+#define ceillog2(x) (luaO_log2((x)-1) + 1)
+
+LUAI_FUNC int luaO_log2 (unsigned int x);
+LUAI_FUNC int luaO_int2fb (unsigned int x);
+LUAI_FUNC int luaO_fb2int (int x);
+LUAI_FUNC int luaO_rawequalObj (const TValue *t1, const TValue *t2);
+LUAI_FUNC int luaO_str2d (const char *s, lua_Number *result);
+LUAI_FUNC const char *luaO_pushvfstring (lua_State *L, const char *fmt,
+ va_list argp);
+LUAI_FUNC const char *luaO_pushfstring (lua_State *L, const char *fmt, ...);
+LUAI_FUNC void luaO_chunkid (char *out, const char *source, size_t len);
+
+
+#endif
+
diff --git a/engines/sword25/util/lua/src/lopcodes.c b/engines/sword25/util/lua/src/lopcodes.c
new file mode 100755
index 0000000000..4cc745230b
--- /dev/null
+++ b/engines/sword25/util/lua/src/lopcodes.c
@@ -0,0 +1,102 @@
+/*
+** $Id: lopcodes.c,v 1.37.1.1 2007/12/27 13:02:25 roberto Exp $
+** See Copyright Notice in lua.h
+*/
+
+
+#define lopcodes_c
+#define LUA_CORE
+
+
+#include "lopcodes.h"
+
+
+/* ORDER OP */
+
+const char *const luaP_opnames[NUM_OPCODES+1] = {
+ "MOVE",
+ "LOADK",
+ "LOADBOOL",
+ "LOADNIL",
+ "GETUPVAL",
+ "GETGLOBAL",
+ "GETTABLE",
+ "SETGLOBAL",
+ "SETUPVAL",
+ "SETTABLE",
+ "NEWTABLE",
+ "SELF",
+ "ADD",
+ "SUB",
+ "MUL",
+ "DIV",
+ "MOD",
+ "POW",
+ "UNM",
+ "NOT",
+ "LEN",
+ "CONCAT",
+ "JMP",
+ "EQ",
+ "LT",
+ "LE",
+ "TEST",
+ "TESTSET",
+ "CALL",
+ "TAILCALL",
+ "RETURN",
+ "FORLOOP",
+ "FORPREP",
+ "TFORLOOP",
+ "SETLIST",
+ "CLOSE",
+ "CLOSURE",
+ "VARARG",
+ NULL
+};
+
+
+#define opmode(t,a,b,c,m) (((t)<<7) | ((a)<<6) | ((b)<<4) | ((c)<<2) | (m))
+
+const lu_byte luaP_opmodes[NUM_OPCODES] = {
+/* T A B C mode opcode */
+ opmode(0, 1, OpArgR, OpArgN, iABC) /* OP_MOVE */
+ ,opmode(0, 1, OpArgK, OpArgN, iABx) /* OP_LOADK */
+ ,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_LOADBOOL */
+ ,opmode(0, 1, OpArgR, OpArgN, iABC) /* OP_LOADNIL */
+ ,opmode(0, 1, OpArgU, OpArgN, iABC) /* OP_GETUPVAL */
+ ,opmode(0, 1, OpArgK, OpArgN, iABx) /* OP_GETGLOBAL */
+ ,opmode(0, 1, OpArgR, OpArgK, iABC) /* OP_GETTABLE */
+ ,opmode(0, 0, OpArgK, OpArgN, iABx) /* OP_SETGLOBAL */
+ ,opmode(0, 0, OpArgU, OpArgN, iABC) /* OP_SETUPVAL */
+ ,opmode(0, 0, OpArgK, OpArgK, iABC) /* OP_SETTABLE */
+ ,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_NEWTABLE */
+ ,opmode(0, 1, OpArgR, OpArgK, iABC) /* OP_SELF */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_ADD */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_SUB */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_MUL */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_DIV */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_MOD */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_POW */
+ ,opmode(0, 1, OpArgR, OpArgN, iABC) /* OP_UNM */
+ ,opmode(0, 1, OpArgR, OpArgN, iABC) /* OP_NOT */
+ ,opmode(0, 1, OpArgR, OpArgN, iABC) /* OP_LEN */
+ ,opmode(0, 1, OpArgR, OpArgR, iABC) /* OP_CONCAT */
+ ,opmode(0, 0, OpArgR, OpArgN, iAsBx) /* OP_JMP */
+ ,opmode(1, 0, OpArgK, OpArgK, iABC) /* OP_EQ */
+ ,opmode(1, 0, OpArgK, OpArgK, iABC) /* OP_LT */
+ ,opmode(1, 0, OpArgK, OpArgK, iABC) /* OP_LE */
+ ,opmode(1, 1, OpArgR, OpArgU, iABC) /* OP_TEST */
+ ,opmode(1, 1, OpArgR, OpArgU, iABC) /* OP_TESTSET */
+ ,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_CALL */
+ ,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_TAILCALL */
+ ,opmode(0, 0, OpArgU, OpArgN, iABC) /* OP_RETURN */
+ ,opmode(0, 1, OpArgR, OpArgN, iAsBx) /* OP_FORLOOP */
+ ,opmode(0, 1, OpArgR, OpArgN, iAsBx) /* OP_FORPREP */
+ ,opmode(1, 0, OpArgN, OpArgU, iABC) /* OP_TFORLOOP */
+ ,opmode(0, 0, OpArgU, OpArgU, iABC) /* OP_SETLIST */
+ ,opmode(0, 0, OpArgN, OpArgN, iABC) /* OP_CLOSE */
+ ,opmode(0, 1, OpArgU, OpArgN, iABx) /* OP_CLOSURE */
+ ,opmode(0, 1, OpArgU, OpArgN, iABC) /* OP_VARARG */
+};
+
diff --git a/engines/sword25/util/lua/src/lopcodes.h b/engines/sword25/util/lua/src/lopcodes.h
new file mode 100755
index 0000000000..41224d6ee1
--- /dev/null
+++ b/engines/sword25/util/lua/src/lopcodes.h
@@ -0,0 +1,268 @@
+/*
+** $Id: lopcodes.h,v 1.125.1.1 2007/12/27 13:02:25 roberto Exp $
+** Opcodes for Lua virtual machine
+** See Copyright Notice in lua.h
+*/
+
+#ifndef lopcodes_h
+#define lopcodes_h
+
+#include "llimits.h"
+
+
+/*===========================================================================
+ We assume that instructions are unsigned numbers.
+ All instructions have an opcode in the first 6 bits.
+ Instructions can have the following fields:
+ `A' : 8 bits
+ `B' : 9 bits
+ `C' : 9 bits
+ `Bx' : 18 bits (`B' and `C' together)
+ `sBx' : signed Bx
+
+ A signed argument is represented in excess K; that is, the number
+ value is the unsigned value minus K. K is exactly the maximum value
+ for that argument (so that -max is represented by 0, and +max is
+ represented by 2*max), which is half the maximum for the corresponding
+ unsigned argument.
+===========================================================================*/
+
+
+enum OpMode {iABC, iABx, iAsBx}; /* basic instruction format */
+
+
+/*
+** size and position of opcode arguments.
+*/
+#define SIZE_C 9
+#define SIZE_B 9
+#define SIZE_Bx (SIZE_C + SIZE_B)
+#define SIZE_A 8
+
+#define SIZE_OP 6
+
+#define POS_OP 0
+#define POS_A (POS_OP + SIZE_OP)
+#define POS_C (POS_A + SIZE_A)
+#define POS_B (POS_C + SIZE_C)
+#define POS_Bx POS_C
+
+
+/*
+** limits for opcode arguments.
+** we use (signed) int to manipulate most arguments,
+** so they must fit in LUAI_BITSINT-1 bits (-1 for sign)
+*/
+#if SIZE_Bx < LUAI_BITSINT-1
+#define MAXARG_Bx ((1<
-
-Buy a copy of this book and
-help to support
-the Lua project.
-
-
-The reference manual is the official definition of the Lua language.
-For a complete introduction to Lua programming, see the book
-Programming in Lua.
-
-
-start
-·
-contents
-·
-index
-·
-português
-·
-español
-
-
-
-
-
-
-
-
-
-
-
-
-The given
-options
-(see below)
-are executed and then
-the Lua program in file
-script
-is loaded and executed.
-The given
-args
-are available to
-script
-as strings in a global table named
-arg.
-If these arguments contain spaces or other characters special to the shell,
-then they should be quoted
-(but note that the quotes will be removed by the shell).
-The arguments in
-arg
-start at 0,
-which contains the string
-'script'.
-The index of the last argument is stored in
-arg.n.
-The arguments given in the command line before
-script,
-including the name of the interpreter,
-are available in negative indices in
-arg.
-
-At the very start,
-before even handling the command line,
-lua
-executes the contents of the environment variable
-LUA_INIT,
-if it is defined.
-If the value of
-LUA_INIT
-is of the form
-'@filename',
-then
-filename
-is executed.
-Otherwise, the string is assumed to be a Lua statement and is executed.
-
-Options start with
-'-'
-and are described below.
-You can use
-'--'
-to signal the end of options.
-
-If no arguments are given,
-then
-"-v -i"
-is assumed when the standard input is a terminal;
-otherwise,
-"-"
-is assumed.
-
-In interactive mode,
-lua
-prompts the user,
-reads lines from the standard input,
-and executes them as they are read.
-If a line does not contain a complete statement,
-then a secondary prompt is displayed and
-lines are read until a complete statement is formed or
-a syntax error is found.
-So, one way to interrupt the reading of an incomplete statement is
-to force a syntax error:
-adding a
-';'
-in the middle of a statement is a sure way of forcing a syntax error
-(except inside multiline strings and comments; these must be closed explicitly).
-If a line starts with
-'=',
-then
-lua
-displays the values of all the expressions in the remainder of the
-line. The expressions must be separated by commas.
-The primary prompt is the value of the global variable
-_PROMPT,
-if this value is a string;
-otherwise, the default prompt is used.
-Similarly, the secondary prompt is the value of the global variable
-_PROMPT2.
-So,
-to change the prompts,
-set the corresponding variable to a string of your choice.
-You can do that after calling the interpreter
-or on the command line
-(but in this case you have to be careful with quotes
-if the prompt string contains a space; otherwise you may confuse the shell.)
-The default prompts are "> " and ">> ".
-
--
-load and execute the standard input as a file,
-that is,
-not interactively,
-even when the standard input is a terminal.
-
--e stat
-execute statement
-stat.
-You need to quote
-stat
-if it contains spaces, quotes,
-or other characters special to the shell.
-
--i
-enter interactive mode after
-script
-is executed.
-
--l name
-call
-require('name')
-before executing
-script.
-Typically used to load libraries.
-
--v
-show version information.
-
-The main advantages of precompiling chunks are:
-faster loading,
-protecting source code from accidental user changes,
-and
-off-line syntax checking.
-
-Precompiling does not imply faster execution
-because in Lua chunks are always compiled into bytecodes before being executed.
-luac
-simply allows those bytecodes to be saved in a file for later execution.
-
-Precompiled chunks are not necessarily smaller than the corresponding source.
-The main goal in precompiling is faster loading.
-
-The binary files created by
-luac
-are portable only among architectures with the same word size and byte order.
-
-luac
-produces a single output file containing the bytecodes
-for all source files given.
-By default,
-the output file is named
-luac.out,
-but you can change this with the
--o
-option.
-
-In the command line,
-you can mix
-text files containing Lua source and
-binary files containing precompiled chunks.
-This is useful because several precompiled chunks,
-even from different (but compatible) platforms,
-can be combined into a single precompiled chunk.
-
-You can use
-'-'
-to indicate the standard input as a source file
-and
-'--'
-to signal the end of options
-(that is,
-all remaining arguments will be treated as files even if they start with
-'-').
-
-The internal format of the binary files produced by
-luac
-is likely to change when a new version of Lua is released.
-So,
-save the source files of all Lua programs that you precompile.
-
-
--l
-produce a listing of the compiled bytecode for Lua's virtual machine.
-Listing bytecodes is useful to learn about Lua's virtual machine.
-If no files are given, then
-luac
-loads
-luac.out
-and lists its contents.
-
--o file
-output to
-file,
-instead of the default
-luac.out.
-(You can use
-'-'
-for standard output,
-but not on platforms that open standard output in text mode.)
-The output file may be a source file because
-all files are loaded before the output file is written.
-Be careful not to overwrite precious files.
-
--p
-load files but do not generate any output file.
-Used mainly for syntax checking and for testing precompiled chunks:
-corrupted files will probably generate errors when loaded.
-Lua always performs a thorough integrity test on precompiled chunks.
-Bytecode that passes this test is completely safe,
-in the sense that it will not break the interpreter.
-However,
-there is no guarantee that such code does anything sensible.
-(None can be given, because the halting problem is unsolvable.)
-If no files are given, then
-luac
-loads
-luac.out
-and tests its contents.
-No messages are displayed if the file passes the integrity test.
-
--s
-strip debug information before writing the output file.
-This saves some space in very large chunks,
-but if errors occur when running a stripped chunk,
-then the error messages may not contain the full information they usually do.
-For instance,
-line numbers and names of local variables are lost.
-
--v
-show version information.
-
-luac.out
-default output file
-
-
-Copyright © 2006-2008 Lua.org, PUC-Rio.
-Freely available under the terms of the
-Lua license.
-
-
-
-
-
-
-
-
-
-Lua is an extension programming language designed to support
-general procedural programming with data description
-facilities.
-It also offers good support for object-oriented programming,
-functional programming, and data-driven programming.
-Lua is intended to be used as a powerful, light-weight
-scripting language for any program that needs one.
-Lua is implemented as a library, written in clean C
-(that is, in the common subset of ANSI C and C++).
-
-
-
-Being an extension language, Lua has no notion of a "main" program:
-it only works embedded in a host client,
-called the embedding program or simply the host.
-This host program can invoke functions to execute a piece of Lua code,
-can write and read Lua variables,
-and can register C functions to be called by Lua code.
-Through the use of C functions, Lua can be augmented to cope with
-a wide range of different domains,
-thus creating customized programming languages sharing a syntactical framework.
-The Lua distribution includes a sample host program called
-Lua is free software,
-and is provided as usual with no guarantees,
-as stated in its license.
-The implementation described in this manual is available
-at Lua's official web site,
-Like any other reference manual,
-this document is dry in places.
-For a discussion of the decisions behind the design of Lua,
-see the technical papers available at Lua's web site.
-For a detailed introduction to programming in Lua,
-see Roberto's book, Programming in Lua (Second Edition).
-
-
-
-
-This section describes the lexis, the syntax, and the semantics of Lua.
-In other words,
-this section describes
-which tokens are valid,
-how they can be combined,
-and what their combinations mean.
-
-
-
-The language constructs will be explained using the usual extended BNF notation,
-in which
-{a} means 0 or more a's, and
-[a] means an optional a.
-Non-terminals are shown like non-terminal,
-keywords are shown like kword,
-and other terminal symbols are shown like `=´.
-The complete syntax of Lua can be found at the end of this manual.
-
-
-
-
-Names
-(also called identifiers)
-in Lua can be any string of letters,
-digits, and underscores,
-not beginning with a digit.
-This coincides with the definition of names in most languages.
-(The definition of letter depends on the current locale:
-any character considered alphabetic by the current locale
-can be used in an identifier.)
-Identifiers are used to name variables and table fields.
-
-
-
-The following keywords are reserved
-and cannot be used as names:
-
-
-
-Lua is a case-sensitive language:
-
-The following strings denote other tokens:
-
-
-Literal strings
-can be delimited by matching single or double quotes,
-and can contain the following C-like escape sequences:
-'
-To put a double (single) quote, a newline, a backslash,
-a carriage return,
-or an embedded zero
-inside a literal string enclosed by double (single) quotes
-you must use an escape sequence.
-Any other character may be directly inserted into the literal.
-(Some control characters may cause problems for the file system,
-but Lua has no problem with them.)
-
-
-
-Literal strings can also be defined using a long format
-enclosed by long brackets.
-We define an opening long bracket of level n as an opening
-square bracket followed by n equal signs followed by another
-opening square bracket.
-So, an opening long bracket of level 0 is written as
-For convenience,
-when the opening long bracket is immediately followed by a newline,
-the newline is not included in the string.
-As an example, in a system using ASCII
-(in which '
-A numerical constant may be written with an optional decimal part
-and an optional decimal exponent.
-Lua also accepts integer hexadecimal constants,
-by prefixing them with
-A comment starts with a double hyphen (
-Lua is a dynamically typed language.
-This means that
-variables do not have types; only values do.
-There are no type definitions in the language.
-All values carry their own type.
-
-
-
-All values in Lua are first-class values.
-This means that all values can be stored in variables,
-passed as arguments to other functions, and returned as results.
-
-
-
-There are eight basic types in Lua:
-nil, boolean, number,
-string, function, userdata,
-thread, and table.
-Nil is the type of the value nil,
-whose main property is to be different from any other value;
-it usually represents the absence of a useful value.
-Boolean is the type of the values false and true.
-Both nil and false make a condition false;
-any other value makes it true.
-Number represents real (double-precision floating-point) numbers.
-(It is easy to build Lua interpreters that use other
-internal representations for numbers,
-such as single-precision float or long integers;
-see file
-Lua can call (and manipulate) functions written in Lua and
-functions written in C
-(see §2.5.8).
-
-
-
-The type userdata is provided to allow arbitrary C data to
-be stored in Lua variables.
-This type corresponds to a block of raw memory
-and has no pre-defined operations in Lua,
-except assignment and identity test.
-However, by using metatables,
-the programmer can define operations for userdata values
-(see §2.8).
-Userdata values cannot be created or modified in Lua,
-only through the C API.
-This guarantees the integrity of data owned by the host program.
-
-
-
-The type thread represents independent threads of execution
-and it is used to implement coroutines (see §2.11).
-Do not confuse Lua threads with operating-system threads.
-Lua supports coroutines on all systems,
-even those that do not support threads.
-
-
-
-The type table implements associative arrays,
-that is, arrays that can be indexed not only with numbers,
-but with any value (except nil).
-Tables can be heterogeneous;
-that is, they can contain values of all types (except nil).
-Tables are the sole data structuring mechanism in Lua;
-they may be used to represent ordinary arrays,
-symbol tables, sets, records, graphs, trees, etc.
-To represent records, Lua uses the field name as an index.
-The language supports this representation by
-providing
-Like indices,
-the value of a table field can be of any type (except nil).
-In particular,
-because functions are first-class values,
-table fields may contain functions.
-Thus tables may also carry methods (see §2.5.9).
-
-
-
-Tables, functions, threads, and (full) userdata values are objects:
-variables do not actually contain these values,
-only references to them.
-Assignment, parameter passing, and function returns
-always manipulate references to such values;
-these operations do not imply any kind of copy.
-
-
-
-The library function
-Lua provides automatic conversion between
-string and number values at run time.
-Any arithmetic operation applied to a string tries to convert
-this string to a number, following the usual conversion rules.
-Conversely, whenever a number is used where a string is expected,
-the number is converted to a string, in a reasonable format.
-For complete control over how numbers are converted to strings,
-use the
-Variables are places that store values.
-
-There are three kinds of variables in Lua:
-global variables, local variables, and table fields.
-
-
-
-A single name can denote a global variable or a local variable
-(or a function's formal parameter,
-which is a particular kind of local variable):
-
-
-Name denotes identifiers, as defined in §2.1.
-
-
-
-Any variable is assumed to be global unless explicitly declared
-as a local (see §2.4.7).
-Local variables are lexically scoped:
-local variables can be freely accessed by functions
-defined inside their scope (see §2.6).
-
-
-
-Before the first assignment to a variable, its value is nil.
-
-
-
-Square brackets are used to index a table:
-
-
-The meaning of accesses to global variables
-and table fields can be changed via metatables.
-An access to an indexed variable
-The syntax
-All global variables live as fields in ordinary Lua tables,
-called environment tables or simply
-environments (see §2.9).
-Each function has its own reference to an environment,
-so that all global variables in this function
-will refer to this environment table.
-When a function is created,
-it inherits the environment from the function that created it.
-To get the environment table of a Lua function,
-you call
-An access to a global variable
-where
-Lua supports an almost conventional set of statements,
-similar to those in Pascal or C.
-This set includes
-assignment, control structures, function calls,
-and variable declarations.
-
-
-
-
-The unit of execution of Lua is called a chunk.
-A chunk is simply a sequence of statements,
-which are executed sequentially.
-Each statement can be optionally followed by a semicolon:
-
-
-There are no empty statements and thus '
-Lua handles a chunk as the body of an anonymous function
-with a variable number of arguments
-(see §2.5.9).
-As such, chunks can define local variables,
-receive arguments, and return values.
-
-
-
-A chunk may be stored in a file or in a string inside the host program.
-When a chunk is executed, first it is pre-compiled into instructions for
-a virtual machine,
-and then the compiled code is executed
-by an interpreter for the virtual machine.
-
-
-
-Chunks may also be pre-compiled into binary form;
-see program
-A block is a list of statements;
-syntactically, a block is the same as a chunk:
-
-
-A block may be explicitly delimited to produce a single statement:
-
-
-Explicit blocks are useful
-to control the scope of variable declarations.
-Explicit blocks are also sometimes used to
-add a return or break statement in the middle
-of another block (see §2.4.4).
-
-
-
-
-
-
-Lua allows multiple assignment.
-Therefore, the syntax for assignment
-defines a list of variables on the left side
-and a list of expressions on the right side.
-The elements in both lists are separated by commas:
-
-
-Expressions are discussed in §2.5.
-
-
-
-Before the assignment,
-the list of values is adjusted to the length of
-the list of variables.
-If there are more values than needed,
-the excess values are thrown away.
-If there are fewer values than needed,
-the list is extended with as many nil's as needed.
-If the list of expressions ends with a function call,
-then all values returned by this call enter in the list of values,
-before the adjustment
-(except when the call is enclosed in parentheses; see §2.5).
-
-
-
-The assignment statement first evaluates all its expressions
-and only then are the assignments performed.
-Thus the code
-
-
-sets
-exchanges the values of
-The meaning of assignments to global variables
-and table fields can be changed via metatables.
-An assignment to an indexed variable
-An assignment to a global variable
-where
-The control structures
-if, while, and repeat have the usual meaning and
-familiar syntax:
-
-
-
-
-
-Lua also has a for statement, in two flavors (see §2.4.5).
-
-
-
-The condition expression of a
-control structure may return any value.
-Both false and nil are considered false.
-All values different from nil and false are considered true
-(in particular, the number 0 and the empty string are also true).
-
-
-
-In the repeat–until loop,
-the inner block does not end at the until keyword,
-but only after the condition.
-So, the condition can refer to local variables
-declared inside the loop block.
-
-
-
-The return statement is used to return values
-from a function or a chunk (which is just a function).
-
-Functions and chunks may return more than one value,
-so the syntax for the return statement is
-
-
-The break statement is used to terminate the execution of a
-while, repeat, or for loop,
-skipping to the next statement after the loop:
-
-
-
-A break ends the innermost enclosing loop.
-
-
-
-The return and break
-statements can only be written as the last statement of a block.
-If it is really necessary to return or break in the
-middle of a block,
-then an explicit inner block can be used,
-as in the idioms
-
-
-The for statement has two forms:
-one numeric and one generic.
-
-
-
-The numeric for loop repeats a block of code while a
-control variable runs through an arithmetic progression.
-It has the following syntax:
-
-
-The block is repeated for name starting at the value of
-the first exp, until it passes the second exp by steps of the
-third exp.
-More precisely, a for statement like
-
-
-is equivalent to the code:
-
-
-Note the following:
-
-
-The generic for statement works over functions,
-called iterators.
-On each iteration, the iterator function is called to produce a new value,
-stopping when this new value is nil.
-The generic for loop has the following syntax:
-
-
-A for statement like
-
-
-is equivalent to the code:
-
-
-Note the following:
-
-
-To allow possible side-effects,
-function calls can be executed as statements:
-
-
-In this case, all returned values are thrown away.
-Function calls are explained in §2.5.8.
-
-
-
-
-
-
-Local variables may be declared anywhere inside a block.
-The declaration may include an initial assignment:
-
-
-If present, an initial assignment has the same semantics
-of a multiple assignment (see §2.4.3).
-Otherwise, all variables are initialized with nil.
-
-
-
-A chunk is also a block (see §2.4.1),
-and so local variables can be declared in a chunk outside any explicit block.
-The scope of such local variables extends until the end of the chunk.
-
-
-
-The visibility rules for local variables are explained in §2.6.
-
-
-
-
-
-
-
-
-The basic expressions in Lua are the following:
-
-
-Numbers and literal strings are explained in §2.1;
-variables are explained in §2.3;
-function definitions are explained in §2.5.9;
-function calls are explained in §2.5.8;
-table constructors are explained in §2.5.7.
-Vararg expressions,
-denoted by three dots ('
-Binary operators comprise arithmetic operators (see §2.5.1),
-relational operators (see §2.5.2), logical operators (see §2.5.3),
-and the concatenation operator (see §2.5.4).
-Unary operators comprise the unary minus (see §2.5.1),
-the unary not (see §2.5.3),
-and the unary length operator (see §2.5.5).
-
-
-
-Both function calls and vararg expressions may result in multiple values.
-If the expression is used as a statement (see §2.4.6)
-(only possible for function calls),
-then its return list is adjusted to zero elements,
-thus discarding all returned values.
-If the expression is used as the last (or the only) element
-of a list of expressions,
-then no adjustment is made
-(unless the call is enclosed in parentheses).
-In all other contexts,
-Lua adjusts the result list to one element,
-discarding all values except the first one.
-
-
-
-Here are some examples:
-
-
-An expression enclosed in parentheses always results in only one value.
-Thus,
-
-Lua supports the usual arithmetic operators:
-the binary
-That is, it is the remainder of a division that rounds
-the quotient towards minus infinity.
-
-
-
-
-
-
-The relational operators in Lua are
-
-
-These operators always result in false or true.
-
-
-
-Equality (
-You can change the way that Lua compares tables and userdata
-by using the "eq" metamethod (see §2.8).
-
-
-
-The conversion rules of §2.2.1
-do not apply to equality comparisons.
-Thus,
-The operator
-The order operators work as follows.
-If both arguments are numbers, then they are compared as such.
-Otherwise, if both arguments are strings,
-then their values are compared according to the current locale.
-Otherwise, Lua tries to call the "lt" or the "le"
-metamethod (see §2.8).
-
-
-
-
-
-
-The logical operators in Lua are
-and, or, and not.
-Like the control structures (see §2.4.4),
-all logical operators consider both false and nil as false
-and anything else as true.
-
-
-
-The negation operator not always returns false or true.
-The conjunction operator and returns its first argument
-if this value is false or nil;
-otherwise, and returns its second argument.
-The disjunction operator or returns its first argument
-if this value is different from nil and false;
-otherwise, or returns its second argument.
-Both and and or use short-cut evaluation;
-that is,
-the second operand is evaluated only if necessary.
-Here are some examples:
-
-
-(In this manual,
---> indicates the result of the preceding expression.)
-
-
-
-
-
-
-The string concatenation operator in Lua is
-denoted by two dots ('
-The length operator is denoted by the unary operator
-The length of a table
-Operator precedence in Lua follows the table below,
-from lower to higher priority:
-
-
-As usual,
-you can use parentheses to change the precedences of an expression.
-The concatenation ('
-Table constructors are expressions that create tables.
-Every time a constructor is evaluated, a new table is created.
-Constructors can be used to create empty tables,
-or to create a table and initialize some of its fields.
-The general syntax for constructors is
-
-
-Each field of the form
-is equivalent to
-
-
-If the last field in the list has the form
-The field list may have an optional trailing separator,
-as a convenience for machine-generated code.
-
-
-
-
-
-
-A function call in Lua has the following syntax:
-
-
-In a function call,
-first prefixexp and args are evaluated.
-If the value of prefixexp has type function,
-then this function is called
-with the given arguments.
-Otherwise, the prefixexp "call" metamethod is called,
-having as first parameter the value of prefixexp,
-followed by the original call arguments
-(see §2.8).
-
-
-
-The form
-
-
-can be used to call "methods".
-A call
-Arguments have the following syntax:
-
-
-All argument expressions are evaluated before the call.
-A call of the form
-As an exception to the free-format syntax of Lua,
-you cannot put a line break before the '
-Lua would see that as a single statement,
-A call of the form
-The syntax for function definition is
-
-
-The following syntactic sugar simplifies function definitions:
-
-
-The statement
-
-
-translates to
-
-
-The statement
-
-
-translates to
-
-
-The statement
-
-
-translates to
-
-
-not to
-
-
-(This only makes a difference when the body of the function
-contains references to
-A function definition is an executable expression,
-whose value has type function.
-When Lua pre-compiles a chunk,
-all its function bodies are pre-compiled too.
-Then, whenever Lua executes the function definition,
-the function is instantiated (or closed).
-This function instance (or closure)
-is the final value of the expression.
-Different instances of the same function
-may refer to different external local variables
-and may have different environment tables.
-
-
-
-Parameters act as local variables that are
-initialized with the argument values:
-
-
-When a function is called,
-the list of arguments is adjusted to
-the length of the list of parameters,
-unless the function is a variadic or vararg function,
-which is
-indicated by three dots ('
-As an example, consider the following definitions:
-
-
-Then, we have the following mapping from arguments to parameters and
-to the vararg expression:
-
-
-Results are returned using the return statement (see §2.4.4).
-If control reaches the end of a function
-without encountering a return statement,
-then the function returns with no results.
-
-
-
-The colon syntax
-is used for defining methods,
-that is, functions that have an implicit extra parameter
-is syntactic sugar for
-
-
-
-Lua is a lexically scoped language.
-The scope of variables begins at the first statement after
-their declaration and lasts until the end of the innermost block that
-includes the declaration.
-Consider the following example:
-
-
-Notice that, in a declaration like
-Because of the lexical scoping rules,
-local variables can be freely accessed by functions
-defined inside their scope.
-A local variable used by an inner function is called
-an upvalue, or external local variable,
-inside the inner function.
-
-
-
-Notice that each execution of a local statement
-defines new local variables.
-Consider the following example:
-
-
-The loop creates ten closures
-(that is, ten instances of the anonymous function).
-Each of these closures uses a different
-Because Lua is an embedded extension language,
-all Lua actions start from C code in the host program
-calling a function from the Lua library (see
-Lua code can explicitly generate an error by calling the
-
-Every value in Lua may have a metatable.
-This metatable is an ordinary Lua table
-that defines the behavior of the original value
-under certain special operations.
-You can change several aspects of the behavior
-of operations over a value by setting specific fields in its metatable.
-For instance, when a non-numeric value is the operand of an addition,
-Lua checks for a function in the field
-We call the keys in a metatable events
-and the values metamethods.
-In the previous example, the event is
-You can query the metatable of any value
-through the
-You can replace the metatable of tables
-through the
-Tables and full userdata have individual metatables
-(although multiple tables and userdata can share their metatables);
-values of all other types share one single metatable per type.
-So, there is one single metatable for all numbers,
-one for all strings, etc.
-
-
-
-A metatable may control how an object behaves in arithmetic operations,
-order comparisons, concatenation, length operation, and indexing.
-A metatable can also define a function to be called when a userdata
-is garbage collected.
-For each of these operations Lua associates a specific key
-called an event.
-When Lua performs one of these operations over a value,
-it checks whether this value has a metatable with the corresponding event.
-If so, the value associated with that key (the metamethod)
-controls how Lua will perform the operation.
-
-
-
-Metatables control the operations listed next.
-Each operation is identified by its corresponding name.
-The key for each operation is a string with its name prefixed by
-two underscores, '
-The code shown here in Lua is only illustrative;
-the real behavior is hard coded in the interpreter
-and it is much more efficient than this simulation.
-All functions used in these descriptions
-(
-This should be read as
-
-
-
-That is, the access to a metamethod does not invoke other metamethods,
-and the access to objects with no metatables does not fail
-(it simply results in nil).
-
-
-
-
-The function
-By using this function,
-the behavior of the
-
-
-
-See §2.5.5 for a description of the length of a table.
-
-The "eq" event is defined as follows:
-
-
-
-
-
-
-
-
-Besides metatables,
-objects of types thread, function, and userdata
-have another table associated with them,
-called their environment.
-Like metatables, environments are regular tables and
-multiple objects can share the same environment.
-
-
-
-Environments associated with userdata have no meaning for Lua.
-It is only a convenience feature for programmers to associate a table to
-a userdata.
-
-
-
-Environments associated with threads are called
-global environments.
-They are used as the default environment for their threads and
-non-nested functions created by the thread
-(through
-Environments associated with C functions can be directly
-accessed by C code (see §3.3).
-They are used as the default environment for other C functions
-created by the function.
-
-
-
-Environments associated with Lua functions are used to resolve
-all accesses to global variables within the function (see §2.3).
-They are used as the default environment for other Lua functions
-created by the function.
-
-
-
-You can change the environment of a Lua function or the
-running thread by calling
-Lua performs automatic memory management.
-This means that
-you have to worry neither about allocating memory for new objects
-nor about freeing it when the objects are no longer needed.
-Lua manages memory automatically by running
-a garbage collector from time to time
-to collect all dead objects
-(that is, these objects that are no longer accessible from Lua).
-All objects in Lua are subject to automatic management:
-tables, userdata, functions, threads, and strings.
-
-
-
-Lua implements an incremental mark-and-sweep collector.
-It uses two numbers to control its garbage-collection cycles:
-the garbage-collector pause and
-the garbage-collector step multiplier.
-
-
-
-The garbage-collector pause
-controls how long the collector waits before starting a new cycle.
-Larger values make the collector less aggressive.
-Values smaller than 1 mean the collector will not wait to
-start a new cycle.
-A value of 2 means that the collector waits for the total memory in use
-to double before starting a new cycle.
-
-
-
-The step multiplier
-controls the relative speed of the collector relative to
-memory allocation.
-Larger values make the collector more aggressive but also increase
-the size of each incremental step.
-Values smaller than 1 make the collector too slow and
-may result in the collector never finishing a cycle.
-The default, 2, means that the collector runs at "twice"
-the speed of memory allocation.
-
-
-
-You can change these numbers by calling
-Using the C API,
-you can set garbage-collector metamethods for userdata (see §2.8).
-These metamethods are also called finalizers.
-Finalizers allow you to coordinate Lua's garbage collection
-with external resource management
-(such as closing files, network or database connections,
-or freeing your own memory).
-
-
-
-Garbage userdata with a field
-At the end of each garbage-collection cycle,
-the finalizers for userdata are called in reverse
-order of their creation,
-among those collected in that cycle.
-That is, the first finalizer to be called is the one associated
-with the userdata created last in the program.
-The userdata itself is freed only in the next garbage-collection cycle.
-
-
-
-
-
-
-A weak table is a table whose elements are
-weak references.
-A weak reference is ignored by the garbage collector.
-In other words,
-if the only references to an object are weak references,
-then the garbage collector will collect this object.
-
-
-
-A weak table can have weak keys, weak values, or both.
-A table with weak keys allows the collection of its keys,
-but prevents the collection of its values.
-A table with both weak keys and weak values allows the collection of
-both keys and values.
-In any case, if either the key or the value is collected,
-the whole pair is removed from the table.
-The weakness of a table is controlled by the
-
-After you use a table as a metatable,
-you should not change the value of its field
-Lua supports coroutines,
-also called collaborative multithreading.
-A coroutine in Lua represents an independent thread of execution.
-Unlike threads in multithread systems, however,
-a coroutine only suspends its execution by explicitly calling
-a yield function.
-
-
-
-You create a coroutine with a call to
-When you first call
-A coroutine can terminate its execution in two ways:
-normally, when its main function returns
-(explicitly or implicitly, after the last instruction);
-and abnormally, if there is an unprotected error.
-In the first case,
-A coroutine yields by calling
-Like
-As an example,
-consider the following code:
-
-
-When you run it, it produces the following output:
-
-
-
-This section describes the C API for Lua, that is,
-the set of C functions available to the host program to communicate
-with Lua.
-All API functions and related types and constants
-are declared in the header file
-Even when we use the term "function",
-any facility in the API may be provided as a macro instead.
-All such macros use each of their arguments exactly once
-(except for the first argument, which is always a Lua state),
-and so do not generate any hidden side-effects.
-
-
-
-As in most C libraries,
-the Lua API functions do not check their arguments for validity or consistency.
-However, you can change this behavior by compiling Lua
-with a proper definition for the macro
-Lua uses a virtual stack to pass values to and from C.
-Each element in this stack represents a Lua value
-(nil, number, string, etc.).
-
-
-
-Whenever Lua calls C, the called function gets a new stack,
-which is independent of previous stacks and of stacks of
-C functions that are still active.
-This stack initially contains any arguments to the C function
-and it is where the C function pushes its results
-to be returned to the caller (see
-For convenience,
-most query operations in the API do not follow a strict stack discipline.
-Instead, they can refer to any element in the stack
-by using an index:
-A positive index represents an absolute stack position
-(starting at 1);
-a negative index represents an offset relative to the top of the stack.
-More specifically, if the stack has n elements,
-then index 1 represents the first element
-(that is, the element that was pushed onto the stack first)
-and
-index n represents the last element;
-index -1 also represents the last element
-(that is, the element at the top)
-and index -n represents the first element.
-We say that an index is valid
-if it lies between 1 and the stack top
-(that is, if
-When you interact with Lua API,
-you are responsible for ensuring consistency.
-In particular,
-you are responsible for controlling stack overflow.
-You can use the function
-Whenever Lua calls C,
-it ensures that at least
-Most query functions accept as indices any value inside the
-available stack space, that is, indices up to the maximum stack size
-you have set through
-Note that 0 is never an acceptable index.
-
-
-
-
-
-
-Unless otherwise noted,
-any function that accepts valid indices can also be called with
-pseudo-indices,
-which represent some Lua values that are accessible to C code
-but which are not in the stack.
-Pseudo-indices are used to access the thread environment,
-the function environment,
-the registry,
-and the upvalues of a C function (see §3.4).
-
-
-
-The thread environment (where global variables live) is
-always at pseudo-index
-To access and change the value of global variables,
-you can use regular table operations over an environment table.
-For instance, to access the value of a global variable, do
-
-
-When a C function is created,
-it is possible to associate some values with it,
-thus creating a C closure;
-these values are called upvalues and are
-accessible to the function whenever it is called
-(see
-Whenever a C function is called,
-its upvalues are located at specific pseudo-indices.
-These pseudo-indices are produced by the macro
-
-Lua provides a registry,
-a pre-defined table that can be used by any C code to
-store whatever Lua value it needs to store.
-This table is always located at pseudo-index
-
-The integer keys in the registry are used by the reference mechanism,
-implemented by the auxiliary library,
-and therefore should not be used for other purposes.
-
-
-
-
-
-
-Internally, Lua uses the C
-Most functions in the API may throw an error,
-for instance due to a memory allocation error.
-The documentation for each function indicates whether
-it can throw errors.
-
-
-
-Inside a C function you can throw an error by calling
-Here we list all functions and types from the C API in
-alphabetical order.
-Each function has an indicator like this:
-[-o, +p, x]
-
-
-
-The first field,
-The type of the memory-allocation function used by Lua states.
-The allocator function must provide a
-functionality similar to
-Here is a simple implementation for the allocator function.
-It is used in the auxiliary library by
-This code assumes
-that
-[-0, +0, -]
-
-Sets a new panic function and returns the old one.
-
-
-
-If an error happens outside any protected environment,
-Lua calls a panic function
-and then calls
-The panic function can access the error message at the top of the stack.
-
-
-
-
-
-
-[-(nargs + 1), +nresults, e]
-
-Calls a function.
-
-
-
-To call a function you must use the following protocol:
-first, the function to be called is pushed onto the stack;
-then, the arguments to the function are pushed
-in direct order;
-that is, the first argument is pushed first.
-Finally you call
-Any error inside the called function is propagated upwards
-(with a
-The following example shows how the host program may do the
-equivalent to this Lua code:
-
-
-Here it is in C:
-
-
-Note that the code above is "balanced":
-at its end, the stack is back to its original configuration.
-This is considered good programming practice.
-
-
-
-
-
-
-Type for C functions.
-
-
-
-In order to communicate properly with Lua,
-a C function must use the following protocol,
-which defines the way parameters and results are passed:
-a C function receives its arguments from Lua in its stack
-in direct order (the first argument is pushed first).
-So, when the function starts,
-
-As an example, the following function receives a variable number
-of numerical arguments and returns their average and sum:
-
-
-[-0, +0, m]
-
-Ensures that there are at least
-[-0, +0, -]
-
-Destroys all objects in the given Lua state
-(calling the corresponding garbage-collection metamethods, if any)
-and frees all dynamic memory used by this state.
-On several platforms, you may not need to call this function,
-because all resources are naturally released when the host program ends.
-On the other hand, long-running programs,
-such as a daemon or a web server,
-might need to release states as soon as they are not needed,
-to avoid growing too large.
-
-
-
-
-
-
-[-n, +1, e]
-
-Concatenates the
-[-0, +(0|1), -]
-
-Calls the C function
-[-0, +1, m]
-
-Creates a new empty table and pushes it onto the stack.
-The new table has space pre-allocated
-for
-[-0, +0, m]
-
-Dumps a function as a binary chunk.
-Receives a Lua function on the top of the stack
-and produces a binary chunk that,
-if loaded again,
-results in a function equivalent to the one dumped.
-As it produces parts of the chunk,
-
-The value returned is the error code returned by the last
-call to the writer;
-0 means no errors.
-
-
-
-This function does not pop the Lua function from the stack.
-
-
-
-
-
-
-[-0, +0, e]
-
-Returns 1 if the two values in acceptable indices
-[-1, +0, v]
-
-Generates a Lua error.
-The error message (which can actually be a Lua value of any type)
-must be on the stack top.
-This function does a long jump,
-and therefore never returns.
-(see
-[-0, +0, e]
-
-Controls the garbage collector.
-
-
-
-This function performs several tasks,
-according to the value of the parameter
-[-0, +0, -]
-
-Returns the memory-allocation function of a given state.
-If
-[-0, +1, -]
-
-Pushes onto the stack the environment table of
-the value at the given index.
-
-
-
-
-
-
-[-0, +1, e]
-
-Pushes onto the stack the value
-[-0, +1, e]
-
-Pushes onto the stack the value of the global
-[-0, +(0|1), -]
-
-Pushes onto the stack the metatable of the value at the given
-acceptable index.
-If the index is not valid,
-or if the value does not have a metatable,
-the function returns 0 and pushes nothing on the stack.
-
-
-
-
-
-
-[-1, +1, e]
-
-Pushes onto the stack the value
-This function pops the key from the stack
-(putting the resulting value in its place).
-As in Lua, this function may trigger a metamethod
-for the "index" event (see §2.8).
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns the index of the top element in the stack.
-Because indices start at 1,
-this result is equal to the number of elements in the stack
-(and so 0 means an empty stack).
-
-
-
-
-
-
-[-1, +1, -]
-
-Moves the top element into the given valid index,
-shifting up the elements above this index to open space.
-Cannot be called with a pseudo-index,
-because a pseudo-index is not an actual stack position.
-
-
-
-
-
-
-The type used by the Lua API to represent integral values.
-
-
-
-By default it is a
-[-0, +0, -]
-
-Returns 1 if the value at the given acceptable index has type boolean,
-and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns 1 if the value at the given acceptable index is a C function,
-and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns 1 if the value at the given acceptable index is a function
-(either C or Lua), and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns 1 if the value at the given acceptable index is a light userdata,
-and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns 1 if the value at the given acceptable index is nil,
-and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns 1 if the given acceptable index is not valid
-(that is, it refers to an element outside the current stack),
-and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns 1 if the given acceptable index is not valid
-(that is, it refers to an element outside the current stack)
-or if the value at this index is nil,
-and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns 1 if the value at the given acceptable index is a number
-or a string convertible to a number,
-and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns 1 if the value at the given acceptable index is a string
-or a number (which is always convertible to a string),
-and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns 1 if the value at the given acceptable index is a table,
-and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns 1 if the value at the given acceptable index is a thread,
-and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns 1 if the value at the given acceptable index is a userdata
-(either full or light), and 0 otherwise.
-
-
-
-
-
-
-[-0, +0, e]
-
-Returns 1 if the value at acceptable index
-[-0, +1, -]
-
-Loads a Lua chunk.
-If there are no errors,
-
-This function only loads a chunk;
-it does not run it.
-
-
-
-
-The
-The
-[-0, +0, -]
-
-Creates a new, independent state.
-Returns
-[-0, +1, m]
-
-Creates a new empty table and pushes it onto the stack.
-It is equivalent to
-[-0, +1, m]
-
-Creates a new thread, pushes it on the stack,
-and returns a pointer to a
-There is no explicit function to close or to destroy a thread.
-Threads are subject to garbage collection,
-like any Lua object.
-
-
-
-
-
-
-[-0, +1, m]
-
-This function allocates a new block of memory with the given size,
-pushes onto the stack a new full userdata with the block address,
-and returns this address.
-
-
-
-Userdata represent C values in Lua.
-A full userdata represents a block of memory.
-It is an object (like a table):
-you must create it, it can have its own metatable,
-and you can detect when it is being collected.
-A full userdata is only equal to itself (under raw equality).
-
-
-
-When Lua collects a full userdata with a
-[-1, +(2|0), e]
-
-Pops a key from the stack,
-and pushes a key-value pair from the table at the given index
-(the "next" pair after the given key).
-If there are no more elements in the table,
-then
-A typical traversal looks like this:
-
-
-While traversing a table,
-do not call
-The type of numbers in Lua.
-By default, it is double, but that can be changed in
-Through the configuration file you can change
-Lua to operate with another type for numbers (e.g., float or long).
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns the "length" of the value at the given acceptable index:
-for strings, this is the string length;
-for tables, this is the result of the length operator ('
-[-(nargs + 1), +(nresults|1), -]
-
-Calls a function in protected mode.
-
-
-
-Both
-If
-Typically, the error handler function is used to add more debug
-information to the error message, such as a stack traceback.
-Such information cannot be gathered after the return of
-The
-[-n, +0, -]
-
-Pops
-[-0, +1, -]
-
-Pushes a boolean value with value
-[-n, +1, m]
-
-Pushes a new C closure onto the stack.
-
-
-
-When a C function is created,
-it is possible to associate some values with it,
-thus creating a C closure (see §3.4);
-these values are then accessible to the function whenever it is called.
-To associate values with a C function,
-first these values should be pushed onto the stack
-(when there are multiple values, the first value is pushed first).
-Then
-[-0, +1, m]
-
-Pushes a C function onto the stack.
-This function receives a pointer to a C function
-and pushes onto the stack a Lua value of type
-Any function to be registered in Lua must
-follow the correct protocol to receive its parameters
-and return its results (see
-
-[-0, +1, m]
-
-Pushes onto the stack a formatted string
-and returns a pointer to this string.
-It is similar to the C function
-[-0, +1, -]
-
-Pushes a number with value
-[-0, +1, -]
-
-Pushes a light userdata onto the stack.
-
-
-
-Userdata represent C values in Lua.
-A light userdata represents a pointer.
-It is a value (like a number):
-you do not create it, it has no individual metatable,
-and it is not collected (as it was never created).
-A light userdata is equal to "any"
-light userdata with the same C address.
-
-
-
-
-
-
-[-0, +1, m]
-
-This macro is equivalent to
-[-0, +1, m]
-
-Pushes the string pointed to by
-[-0, +1, -]
-
-Pushes a nil value onto the stack.
-
-
-
-
-
-
-[-0, +1, -]
-
-Pushes a number with value
-[-0, +1, m]
-
-Pushes the zero-terminated string pointed to by
-[-0, +1, -]
-
-Pushes the thread represented by
-[-0, +1, -]
-
-Pushes a copy of the element at the given valid index
-onto the stack.
-
-
-
-
-
-
-[-0, +1, m]
-
-Equivalent to
-[-0, +0, -]
-
-Returns 1 if the two values in acceptable indices
-[-1, +1, -]
-
-Similar to
-[-0, +1, -]
-
-Pushes onto the stack the value
-[-2, +0, m]
-
-Similar to
-[-1, +0, m]
-
-Does the equivalent of
-This function pops the value from the stack.
-The assignment is raw;
-that is, it does not invoke metamethods.
-
-
-
-
-
-
-The reader function used by
-[-0, +0, e]
-
-Sets the C function
-[-1, +0, -]
-
-Removes the element at the given valid index,
-shifting down the elements above this index to fill the gap.
-Cannot be called with a pseudo-index,
-because a pseudo-index is not an actual stack position.
-
-
-
-
-
-
-[-1, +0, -]
-
-Moves the top element into the given position (and pops it),
-without shifting any element
-(therefore replacing the value at the given position).
-
-
-
-
-
-
-[-?, +?, -]
-
-Starts and resumes a coroutine in a given thread.
-
-
-
-To start a coroutine, you first create a new thread
-(see
-[-0, +0, -]
-
-Changes the allocator function of a given state to
-[-1, +0, -]
-
-Pops a table from the stack and sets it as
-the new environment for the value at the given index.
-If the value at the given index is
-neither a function nor a thread nor a userdata,
-
-[-1, +0, e]
-
-Does the equivalent to
-This function pops the value from the stack.
-As in Lua, this function may trigger a metamethod
-for the "newindex" event (see §2.8).
-
-
-
-
-
-
-[-1, +0, e]
-
-Pops a value from the stack and
-sets it as the new value of global
-[-1, +0, -]
-
-Pops a table from the stack and
-sets it as the new metatable for the value at the given
-acceptable index.
-
-
-
-
-
-
-[-2, +0, e]
-
-Does the equivalent to
-This function pops both the key and the value from the stack.
-As in Lua, this function may trigger a metamethod
-for the "newindex" event (see §2.8).
-
-
-
-
-
-
-[-?, +?, -]
-
-Accepts any acceptable index, or 0,
-and sets the stack top to this index.
-If the new top is larger than the old one,
-then the new elements are filled with nil.
-If
-Opaque structure that keeps the whole state of a Lua interpreter.
-The Lua library is fully reentrant:
-it has no global variables.
-All information about a state is kept in this structure.
-
-
-
-A pointer to this state must be passed as the first argument to
-every function in the library, except to
-[-0, +0, -]
-
-Returns the status of the thread
-The status can be 0 for a normal thread,
-an error code if the thread finished its execution with an error,
-or
-[-0, +0, -]
-
-Converts the Lua value at the given acceptable index to a C boolean
-value (0 or 1).
-Like all tests in Lua,
-
-[-0, +0, -]
-
-Converts a value at the given acceptable index to a C function.
-That value must be a C function;
-otherwise, returns
-[-0, +0, -]
-
-Converts the Lua value at the given acceptable index
-to the signed integral type
-If the number is not an integer,
-it is truncated in some non-specified way.
-
-
-
-
-
-
-[-0, +0, m]
-
-Converts the Lua value at the given acceptable index to a C string.
-If
-
-[-0, +0, -]
-
-Converts the Lua value at the given acceptable index
-to the C type
-[-0, +0, -]
-
-Converts the value at the given acceptable index to a generic
-C pointer (
-Typically this function is used only for debug information.
-
-
-
-
-
-
-[-0, +0, m]
-
-Equivalent to
-[-0, +0, -]
-
-Converts the value at the given acceptable index to a Lua thread
-(represented as
-[-0, +0, -]
-
-If the value at the given acceptable index is a full userdata,
-returns its block address.
-If the value is a light userdata,
-returns its pointer.
-Otherwise, returns
-[-0, +0, -]
-
-Returns the type of the value in the given acceptable index,
-or
-[-0, +0, -]
-
-Returns the name of the type encoded by the value
-The type of the writer function used by
-The writer returns an error code:
-0 means no errors;
-any other value means an error and stops
-[-?, +?, -]
-
-Exchange values between different threads of the same global state.
-
-
-
-This function pops
-[-?, +?, -]
-
-Yields a coroutine.
-
-
-
-This function should only be called as the
-return expression of a C function, as follows:
-
-
-When a C function calls
-Lua has no built-in debugging facilities.
-Instead, it offers a special interface
-by means of functions and hooks.
-This interface allows the construction of different
-kinds of debuggers, profilers, and other tools
-that need "inside information" from the interpreter.
-
-
-
-
-A structure used to carry different pieces of
-information about an active function.
-
-The fields of
-[-0, +0, -]
-
-Returns the current hook function.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns the current hook count.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns the current hook mask.
-
-
-
-
-
-
-[-(0|1), +(0|1|2), m]
-
-Returns information about a specific function or function invocation.
-
-
-
-To get information about a function invocation,
-the parameter
-To get information about a function you push it onto the stack
-and start the
-Each character in the string
-This function returns 0 on error
-(for instance, an invalid option in
-[-0, +(0|1), -]
-
-Gets information about a local variable of a given activation record.
-The parameter
-Variable names starting with '
-Returns
-[-0, +0, -]
-
-Get information about the interpreter runtime stack.
-
-
-
-This function fills parts of a
-[-0, +(0|1), -]
-
-Gets information about a closure's upvalue.
-(For Lua functions,
-upvalues are the external local variables that the function uses,
-and that are consequently included in its closure.)
-
-Returns
-Type for debugging hook functions.
-
-
-
-Whenever a hook is called, its
-While Lua is running a hook, it disables other calls to hooks.
-Therefore, if a hook calls back Lua to execute a function or a chunk,
-this execution occurs without any calls to hooks.
-
-
-
-
-
-
-[-0, +0, -]
-
-Sets the debugging hook function.
-
-
-
-Argument
-A hook is disabled by setting
-[-(0|1), +0, -]
-
-Sets the value of a local variable of a given activation record.
-Parameters
-Returns
-[-(0|1), +0, -]
-
-Sets the value of a closure's upvalue.
-It assigns the value at the top of the stack
-to the upvalue and returns its name.
-It also pops the value from the stack.
-Parameters
-Returns
-
-The auxiliary library provides several convenient functions
-to interface C with Lua.
-While the basic API provides the primitive functions for all
-interactions between C and Lua,
-the auxiliary library provides higher-level functions for some
-common tasks.
-
-
-
-All functions from the auxiliary library
-are defined in header file
-All functions in the auxiliary library are built on
-top of the basic API,
-and so they provide nothing that cannot be done with this API.
-
-
-
-Several functions in the auxiliary library are used to
-check C function arguments.
-Their names are always
-Here we list all functions and types from the auxiliary library
-in alphabetical order.
-
-
-
-
-[-0, +0, m]
-
-Adds the character
-[-0, +0, m]
-
-Adds the string pointed to by
-[-0, +0, m]
-
-Adds to the buffer
-[-0, +0, m]
-
-Adds the zero-terminated string pointed to by
-[-1, +0, m]
-
-Adds the value at the top of the stack
-to the buffer
-This is the only function on string buffers that can (and must)
-be called with an extra element on the stack,
-which is the value to be added to the buffer.
-
-
-
-
-
-
-[-0, +0, v]
-
-Checks whether
-[-0, +0, v]
-
-Raises an error with the following message,
-where
-This function never returns,
-but it is an idiom to use it in C functions
-as
-Type for a string buffer.
-
-
-
-A string buffer allows C code to build Lua strings piecemeal.
-Its pattern of use is as follows:
-
-
-During its normal operation,
-a string buffer uses a variable number of stack slots.
-So, while using a buffer, you cannot assume that you know where
-the top of the stack is.
-You can use the stack between successive calls to buffer operations
-as long as that use is balanced;
-that is,
-when you call a buffer operation,
-the stack is at the same level
-it was immediately after the previous buffer operation.
-(The only exception to this rule is
-[-0, +0, -]
-
-Initializes a buffer
-[-0, +(0|1), e]
-
-Calls a metamethod.
-
-
-
-If the object at index
-[-0, +0, v]
-
-Checks whether the function has an argument
-of any type (including nil) at position
-[-0, +0, v]
-
-Checks whether the function argument
-[-0, +0, v]
-
-Checks whether the function argument
-[-0, +0, v]
-
-Checks whether the function argument
-[-0, +0, v]
-
-Checks whether the function argument
-This function uses
-[-0, +0, v]
-
-Checks whether the function argument
-[-0, +0, v]
-
-Checks whether the function argument
-If
-This is a useful function for mapping strings to C enums.
-(The usual convention in Lua libraries is
-to use strings instead of numbers to select options.)
-
-
-
-
-
-
-[-0, +0, v]
-
-Grows the stack size to
-[-0, +0, v]
-
-Checks whether the function argument
-This function uses
-[-0, +0, v]
-
-Checks whether the function argument
-[-0, +0, v]
-
-Checks whether the function argument
-[-0, +?, m]
-
-Loads and runs the given file.
-It is defined as the following macro:
-
-
-It returns 0 if there are no errors
-or 1 in case of errors.
-
-
-
-
-
-
-[-0, +?, m]
-
-Loads and runs the given string.
-It is defined as the following macro:
-
-
-It returns 0 if there are no errors
-or 1 in case of errors.
-
-
-
-
-
-
-[-0, +0, v]
-
-Raises an error.
-The error message format is given by
-This function never returns,
-but it is an idiom to use it in C functions
-as
-[-0, +(0|1), m]
-
-Pushes onto the stack the field
-[-0, +1, -]
-
-Pushes onto the stack the metatable associated with name
-[-0, +1, m]
-
-Creates a copy of string
-[-0, +1, m]
-
-Loads a buffer as a Lua chunk.
-This function uses
-This function returns the same results as
-[-0, +1, m]
-
-Loads a file as a Lua chunk.
-This function uses
-This function returns the same results as
-As
-[-0, +1, m]
-
-Loads a string as a Lua chunk.
-This function uses
-This function returns the same results as
-Also as
-[-0, +1, m]
-
-If the registry already has the key
-In both cases pushes onto the stack the final value associated
-with
-[-0, +0, -]
-
-Creates a new Lua state.
-It calls
-Returns the new state,
-or
-[-0, +0, m]
-
-Opens all standard Lua libraries into the given state.
-
-
-
-
-
-
-[-0, +0, v]
-
-If the function argument
-[-0, +0, v]
-
-If the function argument
-[-0, +0, v]
-
-If the function argument
-[-0, +0, v]
-
-If the function argument
-If
-[-0, +0, v]
-
-If the function argument
-[-0, +0, v]
-
-If the function argument
-[-0, +0, -]
-
-Returns an address to a space of size
-[-?, +1, m]
-
-Finishes the use of buffer
-[-1, +0, m]
-
-Creates and returns a reference,
-in the table at index
-A reference is a unique integer key.
-As long as you do not manually add integer keys into table
-If the object at the top of the stack is nil,
-
-Type for arrays of functions to be registered by
-
-[-(0|1), +1, m]
-
-Opens a library.
-
-
-
-When called with
-When called with a non-null
-In any case the function leaves the table
-on the top of the stack.
-
-
-
-
-
-
-[-0, +0, -]
-
-Returns the name of the type of the value at the given index.
-
-
-
-
-
-
-[-0, +0, v]
-
-Generates an error with a message like the following:
-
-
-where
-[-0, +0, -]
-
-Releases reference
-If
-[-0, +1, m]
-
-Pushes onto the stack a string identifying the current position
-of the control at level
-Level 0 is the running function,
-level 1 is the function that called the running function,
-etc.
-
-
-
-This function is used to build a prefix for error messages.
-
-
-
-
-
-
-
-
-The standard Lua libraries provide useful functions
-that are implemented directly through the C API.
-Some of these functions provide essential services to the language
-(e.g.,
-All libraries are implemented through the official C API
-and are provided as separate C modules.
-Currently, Lua has the following standard libraries:
-
-
-Except for the basic and package libraries,
-each library provides all its functions as fields of a global table
-or as methods of its objects.
-
-
-
-To have access to these libraries,
-the C host program should call the
-The basic library provides some core functions to Lua.
-If you do not include this library in your application,
-you should check carefully whether you need to provide
-implementations for some of its facilities.
-
-
-
-
-
-This function is a generic interface to the garbage collector.
-It performs different functions according to its first argument,
-
-
-Usually,
-
-
-
-If
-
-Returns three values: an iterator function, the table
-will iterate over the pairs (
-
-Loads a chunk using function
-If there are no errors,
-returns the compiled chunk as a function;
-otherwise, returns nil plus the error message.
-The environment of the returned function is the global environment.
-
-
-
-
-
-Similar to
-
-Similar to
-To load and run a given string, use the idiom
-
-
-When absent,
-
-
-Allows a program to traverse all fields of a table.
-Its first argument is a table and its second argument
-is an index in this table.
-
-The order in which the indices are enumerated is not specified,
-even for numeric indices.
-(To traverse a table in numeric order,
-use a numerical for or the
-The behavior of
-
-Returns three values: the
-will iterate over all key–value pairs of table
-See function
-
-Calls function
-
-
-
-
-This function returns
-
-If
-
-Sets the environment to be used by the given function.
-
-As a special case, when
-
-Sets the metatable for the given table.
-(You cannot change the metatable of other types from Lua, only from C.)
-If
-This function returns
-
-An optional argument specifies the base to interpret the numeral.
-The base may be any integer between 2 and 36, inclusive.
-In bases above 10, the letter '
-
-If the metatable of
-
-
-except that the above code can be written only for a fixed number
-of elements.
-By default,
-
-
-This function is similar to
-
-The operations related to coroutines comprise a sub-library of
-the basic library and come inside the table
-
-Creates a new coroutine, with body
-
-Starts or continues the execution of coroutine
-If the coroutine runs without any errors,
-
-
-Returns the running coroutine,
-or nil when called by the main thread.
-
-
-
-
-
-
-Returns the status of coroutine
-
-Creates a new coroutine, with body
-
-Suspends the execution of the calling coroutine.
-The coroutine cannot be running a C function,
-a metamethod, or an iterator.
-Any arguments to
-The package library provides basic
-facilities for loading and building modules in Lua.
-It exports two of its functions directly in the global environment:
-
-
-Creates a module.
-If there is a table in
-If
-This function may receive optional options after
-the module name,
-where each option is a function to be applied over the module.
-
-
-
-
-
-
-Loads the given module.
-The function starts by looking into the
-To find a loader,
-
-First
-Once a loader is found,
-
-If there is any error loading or running the module,
-or if it cannot find any loader for the module,
-then
-
-The path used by
-Lua initializes the C path
-
-
-A table used by
-
-A table used by
-Each entry in this table is a searcher function.
-When looking for a module,
-
-The first searcher simply looks for a loader in the
-
-The second searcher looks for a loader as a Lua library,
-using the path stored at
-the search for a Lua file for module
-The third searcher looks for a loader as a C library,
-using the path given by the variable
-the searcher for module
-The fourth searcher tries an all-in-one loader.
-It searches the C path for a library for
-the root name of the given module.
-For instance, when requiring
-
-Dynamically links the host program with the C library
-This is a low-level function.
-It completely bypasses the package and module system.
-Unlike
-This function is not supported by ANSI C.
-As such, it is only available on some platforms
-(Windows, Linux, Mac OS X, Solaris, BSD,
-plus other Unix systems that support the
-
-The path used by
-At start-up, Lua initializes this variable with
-the value of the environment variable
-
-A table to store loaders for specific modules
-(see
-
-Sets a metatable for
-This library provides generic functions for string manipulation,
-such as finding and extracting substrings, and pattern matching.
-When indexing a string in Lua, the first character is at position 1
-(not at 0, as in C).
-Indices are allowed to be negative and are interpreted as indexing backwards,
-from the end of the string.
-Thus, the last character is at position -1, and so on.
-
-
-
-The string library provides all its functions inside the table
-
-
-Note that numerical codes are not necessarily portable across platforms.
-
-
-
-
-
-
-Note that numerical codes are not necessarily portable across platforms.
-
-
-
-
-
-
-Returns a string containing a binary representation of the given function,
-so that a later
-
-If the pattern has captures,
-then in a successful match
-the captured values are also returned,
-after the two indices.
-
-
-
-
-
-
-will produce the string:
-
-
-The options
-This function does not accept string values
-containing embedded zeros,
-except as arguments to the
-
-As an example, the following loop
-
-
-will iterate over all the words from string
-For this function, a '
-
-If
-If
-If
-If the value returned by the table query or by the function call
-is a string or a number,
-then it is used as the replacement string;
-otherwise, if it is false or nil,
-then there is no replacement
-(that is, the original match is kept in the string).
-
-
-
-Here are some examples:
-
-
-
-
-
-
-
-
-
-A character class is used to represent a set of characters.
-The following combinations are allowed in describing a character class:
-
-
-The interaction between ranges and classes is not defined.
-Therefore, patterns like
-For all classes represented by single letters (
-The definitions of letter, space, and other character groups
-depend on the current locale.
-In particular, the class
-A pattern item may be
-
-
-A pattern is a sequence of pattern items.
-A '
-A pattern may contain sub-patterns enclosed in parentheses;
-they describe captures.
-When a match succeeds, the substrings of the subject string
-that match captures are stored (captured) for future use.
-Captures are numbered according to their left parentheses.
-For instance, in the pattern
-As a special case, the empty capture
-A pattern cannot contain embedded zeros. Use
-This library provides generic functions for table manipulation.
-It provides all its functions inside the table
-Most functions in the table library assume that the table
-represents an array or a list.
-For these functions, when we talk about the "length" of a table
-we mean the result of the length operator.
-
-
-
-
-
-Inserts element
-
-Returns the largest positive numerical index of the given table,
-or zero if the table has no positive numerical indices.
-(To do its job this function does a linear traversal of
-the whole table.)
-
-
-
-
-
-
-Removes from
-
-The sort algorithm is not stable;
-that is, elements considered equal by the given order
-may have their relative positions changed by the sort.
-
-
-
-
-
-
-
-
-This library is an interface to the standard C math library.
-It provides all its functions inside the table
-
-Returns the absolute value of
-
-Returns the arc cosine of
-
-Returns the arc sine of
-
-Returns the arc tangent of
-
-Returns the arc tangent of
-
-Returns the smallest integer larger than or equal to
-
-Returns the cosine of
-
-Returns the hyperbolic cosine of
-
-Returns the angle
-
-Returns the value ex.
-
-
-
-
-
-
-Returns the largest integer smaller than or equal to
-
-Returns the remainder of the division of
-
-Returns
-
-The value
-
-Returns m2e (
-
-Returns the natural logarithm of
-
-Returns the base-10 logarithm of
-
-Returns the maximum value among its arguments.
-
-
-
-
-
-
-Returns the minimum value among its arguments.
-
-
-
-
-
-
-Returns two numbers,
-the integral part of
-
-The value of pi.
-
-
-
-
-
-
-Returns xy.
-(You can also use the expression
-
-Returns the angle
-
-This function is an interface to the simple
-pseudo-random generator function
-When called without arguments,
-returns a uniform pseudo-random real number
-in the range [0,1).
-When called with an integer number
-
-Sets
-
-Returns the sine of
-
-Returns the hyperbolic sine of
-
-Returns the square root of
-
-Returns the tangent of
-
-Returns the hyperbolic tangent of
-The I/O library provides two different styles for file manipulation.
-The first one uses implicit file descriptors;
-that is, there are operations to set a default input file and a
-default output file,
-and all input/output operations are over these default files.
-The second style uses explicit file descriptors.
-
-
-
-When using implicit file descriptors,
-all operations are supplied by table
-The table
-Unless otherwise stated,
-all I/O functions return nil on failure
-(plus an error message as a second result and
-a system-dependent error code as a third result)
-and some value different from nil on success.
-
-
-
-
-Equivalent to
-
-Equivalent to
-
-When called with a file name, it opens the named file (in text mode),
-and sets its handle as the default input file.
-When called with a file handle,
-it simply sets this file handle as the default input file.
-When called without parameters,
-it returns the current default input file.
-
-
-
-In case of errors this function raises the error,
-instead of returning an error code.
-
-
-
-
-
-
-Opens the given file name in read mode
-and returns an iterator function that,
-each time it is called,
-returns a new line from the file.
-Therefore, the construction
-
-
-will iterate over all lines of the file.
-When the iterator function detects the end of file,
-it returns nil (to finish the loop) and automatically closes the file.
-
-
-
-The call
-
-This function opens a file,
-in the mode specified in the string
-The
-The
-
-Similar to
-
-Starts program
-This function is system dependent and is not available
-on all platforms.
-
-
-
-
-
-
-Equivalent to
-
-Returns a handle for a temporary file.
-This file is opened in update mode
-and it is automatically removed when the program ends.
-
-
-
-
-
-
-Checks whether
-
-Equivalent to
-
-Closes
-
-Saves any written data to
-
-Returns an iterator function that,
-each time it is called,
-returns a new line from the file.
-Therefore, the construction
-
-
-will iterate over all lines of the file.
-(Unlike
-
-Reads the file
-The available formats are
-
-
-
-Sets and gets the file position,
-measured from the beginning of the file,
-to the position given by
-In case of success, function
-The default value for
-
-Sets the buffering mode for an output file.
-There are three available modes:
-
-
-For the last two cases,
-
-Writes the value of each of its arguments to
-the
-This library is implemented through table
-
-Returns an approximation of the amount in seconds of CPU time
-used by the program.
-
-
-
-
-
-
-Returns a string or a table containing date and time,
-formatted according to the given string
-If the
-If
-If
-When called without arguments,
-
-
-Returns the number of seconds from time
-
-This function is equivalent to the C function
-
-Calls the C function
-
-Returns the value of the process environment variable
-
-Deletes the file or directory with the given name.
-Directories must be empty to be removed.
-If this function fails, it returns nil,
-plus a string describing the error.
-
-
-
-
-
-
-Renames file or directory named
-
-Sets the current locale of the program.
-
-If
-When called with nil as the first argument,
-this function only returns the name of the current locale
-for the given category.
-
-
-
-
-
-
-Returns the current time when called without arguments,
-or a time representing the date and time specified by the given table.
-This table must have fields
-The returned value is a number, whose meaning depends on your system.
-In POSIX, Windows, and some other systems, this number counts the number
-of seconds since some given start time (the "epoch").
-In other systems, the meaning is not specified,
-and the number returned by
-
-Returns a string with a file name that can
-be used for a temporary file.
-The file must be explicitly opened before its use
-and explicitly removed when no longer needed.
-
-
-
-
-
-
-
-
-This library provides
-the functionality of the debug interface to Lua programs.
-You should exert care when using this library.
-The functions provided here should be used exclusively for debugging
-and similar tasks, such as profiling.
-Please resist the temptation to use them as a
-usual programming tool:
-they can be very slow.
-Moreover, several of these functions
-violate some assumptions about Lua code
-(e.g., that variables local to a function
-cannot be accessed from outside or
-that userdata metatables cannot be changed by Lua code)
-and therefore can compromise otherwise secure code.
-
-
-
-All functions in this library are provided
-inside the
-
-Enters an interactive mode with the user,
-running each string that the user enters.
-Using simple commands and other debug facilities,
-the user can inspect global and local variables,
-change their values, evaluate expressions, and so on.
-A line containing only the word
-Note that commands for
-
-
-Returns the current hook settings of the thread, as three values:
-the current hook function, the current hook mask,
-and the current hook count
-(as set by the
-
-Returns a table with information about a function.
-You can give the function directly,
-or you can give a number as the value of
-The returned table may contain all the fields returned by
-For instance, the expression
-
-This function returns the name and the value of the local variable
-with index
-Variable names starting with '
-
-Returns the metatable of the given
-
-Returns the registry table (see §3.5).
-
-
-
-
-
-
-This function returns the name and the value of the upvalue
-with index
-
-Sets the environment of the given
-
-Sets the given function as a hook.
-The string
-With a
-When called without arguments,
-
-When the hook is called, its first parameter is a string
-describing the event that has triggered its call:
-
-
-This function assigns the value
-
-Sets the metatable for the given
-
-This function assigns the value
-
-Returns a string with a traceback of the call stack.
-An optional
-Although Lua has been designed as an extension language,
-to be embedded in a host C program,
-it is also frequently used as a stand-alone language.
-An interpreter for Lua as a stand-alone language,
-called simply
-The options are:
-
-
-After handling its options,
-Before running any argument,
-the interpreter checks for an environment variable
-All options are handled in order, except
-will first set
-Before starting to run the script,
-
-the interpreter first runs the file
-and finally runs the file
-In interactive mode,
-if you write an incomplete statement,
-the interpreter waits for its completion
-by issuing a different prompt.
-
-
-
-If the global variable
-(The outer pair of quotes is for the shell,
-the inner pair is for Lua.)
-Note the use of
-To allow the use of Lua as a
-script interpreter in Unix systems,
-the stand-alone interpreter skips
-the first line of a chunk if it starts with
-(Of course,
-the location of the Lua interpreter may be different in your machine.
-If
-is a more portable solution.)
-
-
-
-
-Here we list the incompatibilities that you may find when moving a program
-from Lua 5.0 to Lua 5.1.
-You can avoid most of the incompatibilities compiling Lua with
-appropriate options (see file
-Here is the complete syntax of Lua in extended BNF.
-(It does not describe operator precedences.)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
- lsizenode))
+
+
+#define luaO_nilobject (&luaO_nilobject_)
+
+LUAI_DATA const TValue luaO_nilobject_;
+
+#define ceillog2(x) (luaO_log2((x)-1) + 1)
+
+LUAI_FUNC int luaO_log2 (unsigned int x);
+LUAI_FUNC int luaO_int2fb (unsigned int x);
+LUAI_FUNC int luaO_fb2int (int x);
+LUAI_FUNC int luaO_rawequalObj (const TValue *t1, const TValue *t2);
+LUAI_FUNC int luaO_str2d (const char *s, lua_Number *result);
+LUAI_FUNC const char *luaO_pushvfstring (lua_State *L, const char *fmt,
+ va_list argp);
+LUAI_FUNC const char *luaO_pushfstring (lua_State *L, const char *fmt, ...);
+LUAI_FUNC void luaO_chunkid (char *out, const char *source, size_t len);
+
+
+#endif
+
diff --git a/engines/sword25/util/lua/lopcodes.c b/engines/sword25/util/lua/lopcodes.c
new file mode 100755
index 0000000000..4cc745230b
--- /dev/null
+++ b/engines/sword25/util/lua/lopcodes.c
@@ -0,0 +1,102 @@
+/*
+** $Id: lopcodes.c,v 1.37.1.1 2007/12/27 13:02:25 roberto Exp $
+** See Copyright Notice in lua.h
+*/
+
+
+#define lopcodes_c
+#define LUA_CORE
+
+
+#include "lopcodes.h"
+
+
+/* ORDER OP */
+
+const char *const luaP_opnames[NUM_OPCODES+1] = {
+ "MOVE",
+ "LOADK",
+ "LOADBOOL",
+ "LOADNIL",
+ "GETUPVAL",
+ "GETGLOBAL",
+ "GETTABLE",
+ "SETGLOBAL",
+ "SETUPVAL",
+ "SETTABLE",
+ "NEWTABLE",
+ "SELF",
+ "ADD",
+ "SUB",
+ "MUL",
+ "DIV",
+ "MOD",
+ "POW",
+ "UNM",
+ "NOT",
+ "LEN",
+ "CONCAT",
+ "JMP",
+ "EQ",
+ "LT",
+ "LE",
+ "TEST",
+ "TESTSET",
+ "CALL",
+ "TAILCALL",
+ "RETURN",
+ "FORLOOP",
+ "FORPREP",
+ "TFORLOOP",
+ "SETLIST",
+ "CLOSE",
+ "CLOSURE",
+ "VARARG",
+ NULL
+};
+
+
+#define opmode(t,a,b,c,m) (((t)<<7) | ((a)<<6) | ((b)<<4) | ((c)<<2) | (m))
+
+const lu_byte luaP_opmodes[NUM_OPCODES] = {
+/* T A B C mode opcode */
+ opmode(0, 1, OpArgR, OpArgN, iABC) /* OP_MOVE */
+ ,opmode(0, 1, OpArgK, OpArgN, iABx) /* OP_LOADK */
+ ,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_LOADBOOL */
+ ,opmode(0, 1, OpArgR, OpArgN, iABC) /* OP_LOADNIL */
+ ,opmode(0, 1, OpArgU, OpArgN, iABC) /* OP_GETUPVAL */
+ ,opmode(0, 1, OpArgK, OpArgN, iABx) /* OP_GETGLOBAL */
+ ,opmode(0, 1, OpArgR, OpArgK, iABC) /* OP_GETTABLE */
+ ,opmode(0, 0, OpArgK, OpArgN, iABx) /* OP_SETGLOBAL */
+ ,opmode(0, 0, OpArgU, OpArgN, iABC) /* OP_SETUPVAL */
+ ,opmode(0, 0, OpArgK, OpArgK, iABC) /* OP_SETTABLE */
+ ,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_NEWTABLE */
+ ,opmode(0, 1, OpArgR, OpArgK, iABC) /* OP_SELF */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_ADD */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_SUB */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_MUL */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_DIV */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_MOD */
+ ,opmode(0, 1, OpArgK, OpArgK, iABC) /* OP_POW */
+ ,opmode(0, 1, OpArgR, OpArgN, iABC) /* OP_UNM */
+ ,opmode(0, 1, OpArgR, OpArgN, iABC) /* OP_NOT */
+ ,opmode(0, 1, OpArgR, OpArgN, iABC) /* OP_LEN */
+ ,opmode(0, 1, OpArgR, OpArgR, iABC) /* OP_CONCAT */
+ ,opmode(0, 0, OpArgR, OpArgN, iAsBx) /* OP_JMP */
+ ,opmode(1, 0, OpArgK, OpArgK, iABC) /* OP_EQ */
+ ,opmode(1, 0, OpArgK, OpArgK, iABC) /* OP_LT */
+ ,opmode(1, 0, OpArgK, OpArgK, iABC) /* OP_LE */
+ ,opmode(1, 1, OpArgR, OpArgU, iABC) /* OP_TEST */
+ ,opmode(1, 1, OpArgR, OpArgU, iABC) /* OP_TESTSET */
+ ,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_CALL */
+ ,opmode(0, 1, OpArgU, OpArgU, iABC) /* OP_TAILCALL */
+ ,opmode(0, 0, OpArgU, OpArgN, iABC) /* OP_RETURN */
+ ,opmode(0, 1, OpArgR, OpArgN, iAsBx) /* OP_FORLOOP */
+ ,opmode(0, 1, OpArgR, OpArgN, iAsBx) /* OP_FORPREP */
+ ,opmode(1, 0, OpArgN, OpArgU, iABC) /* OP_TFORLOOP */
+ ,opmode(0, 0, OpArgU, OpArgU, iABC) /* OP_SETLIST */
+ ,opmode(0, 0, OpArgN, OpArgN, iABC) /* OP_CLOSE */
+ ,opmode(0, 1, OpArgU, OpArgN, iABx) /* OP_CLOSURE */
+ ,opmode(0, 1, OpArgU, OpArgN, iABC) /* OP_VARARG */
+};
+
diff --git a/engines/sword25/util/lua/lopcodes.h b/engines/sword25/util/lua/lopcodes.h
new file mode 100755
index 0000000000..41224d6ee1
--- /dev/null
+++ b/engines/sword25/util/lua/lopcodes.h
@@ -0,0 +1,268 @@
+/*
+** $Id: lopcodes.h,v 1.125.1.1 2007/12/27 13:02:25 roberto Exp $
+** Opcodes for Lua virtual machine
+** See Copyright Notice in lua.h
+*/
+
+#ifndef lopcodes_h
+#define lopcodes_h
+
+#include "llimits.h"
+
+
+/*===========================================================================
+ We assume that instructions are unsigned numbers.
+ All instructions have an opcode in the first 6 bits.
+ Instructions can have the following fields:
+ `A' : 8 bits
+ `B' : 9 bits
+ `C' : 9 bits
+ `Bx' : 18 bits (`B' and `C' together)
+ `sBx' : signed Bx
+
+ A signed argument is represented in excess K; that is, the number
+ value is the unsigned value minus K. K is exactly the maximum value
+ for that argument (so that -max is represented by 0, and +max is
+ represented by 2*max), which is half the maximum for the corresponding
+ unsigned argument.
+===========================================================================*/
+
+
+enum OpMode {iABC, iABx, iAsBx}; /* basic instruction format */
+
+
+/*
+** size and position of opcode arguments.
+*/
+#define SIZE_C 9
+#define SIZE_B 9
+#define SIZE_Bx (SIZE_C + SIZE_B)
+#define SIZE_A 8
+
+#define SIZE_OP 6
+
+#define POS_OP 0
+#define POS_A (POS_OP + SIZE_OP)
+#define POS_C (POS_A + SIZE_A)
+#define POS_B (POS_C + SIZE_C)
+#define POS_Bx POS_C
+
+
+/*
+** limits for opcode arguments.
+** we use (signed) int to manipulate most arguments,
+** so they must fit in LUAI_BITSINT-1 bits (-1 for sign)
+*/
+#if SIZE_Bx < LUAI_BITSINT-1
+#define MAXARG_Bx ((1<
-
-
-
-This is an online version of
-
-Lua 5.1 Reference Manual
-
-
-
-
-
-Lua 5.1 Reference Manual
-
by R. Ierusalimschy, L. H. de Figueiredo, W. Celes
-
Lua.org, August 2006
-
ISBN 85-903798-3-3
-
-
-
-
-
-Copyright © 2006-2008 Lua.org, PUC-Rio.
-Freely available under the terms of the
-Lua license.
-
-Contents
-
-
-
-
-
-
-
-
-
-Index
-
-
-Last update:
-Sat Jan 19 13:24:29 BRST 2008
-
-
-
-
-
diff --git a/engines/sword25/util/lua/doc/cover.png b/engines/sword25/util/lua/doc/cover.png
deleted file mode 100755
index 2dbb198123..0000000000
Binary files a/engines/sword25/util/lua/doc/cover.png and /dev/null differ
diff --git a/engines/sword25/util/lua/doc/logo.gif b/engines/sword25/util/lua/doc/logo.gif
deleted file mode 100755
index 2f5e4ac2e7..0000000000
Binary files a/engines/sword25/util/lua/doc/logo.gif and /dev/null differ
diff --git a/engines/sword25/util/lua/doc/lua.1 b/engines/sword25/util/lua/doc/lua.1
deleted file mode 100755
index 24809cc6c1..0000000000
--- a/engines/sword25/util/lua/doc/lua.1
+++ /dev/null
@@ -1,163 +0,0 @@
-.\" $Id: lua.man,v 1.11 2006/01/06 16:03:34 lhf Exp $
-.TH LUA 1 "$Date: 2006/01/06 16:03:34 $"
-.SH NAME
-lua \- Lua interpreter
-.SH SYNOPSIS
-.B lua
-[
-.I options
-]
-[
-.I script
-[
-.I args
-]
-]
-.SH DESCRIPTION
-.B lua
-is the stand-alone Lua interpreter.
-It loads and executes Lua programs,
-either in textual source form or
-in precompiled binary form.
-(Precompiled binaries are output by
-.BR luac ,
-the Lua compiler.)
-.B lua
-can be used as a batch interpreter and also interactively.
-.LP
-The given
-.I options
-(see below)
-are executed and then
-the Lua program in file
-.I script
-is loaded and executed.
-The given
-.I args
-are available to
-.I script
-as strings in a global table named
-.BR arg .
-If these arguments contain spaces or other characters special to the shell,
-then they should be quoted
-(but note that the quotes will be removed by the shell).
-The arguments in
-.B arg
-start at 0,
-which contains the string
-.RI ' script '.
-The index of the last argument is stored in
-.BR arg.n .
-The arguments given in the command line before
-.IR script ,
-including the name of the interpreter,
-are available in negative indices in
-.BR arg .
-.LP
-At the very start,
-before even handling the command line,
-.B lua
-executes the contents of the environment variable
-.BR LUA_INIT ,
-if it is defined.
-If the value of
-.B LUA_INIT
-is of the form
-.RI '@ filename ',
-then
-.I filename
-is executed.
-Otherwise, the string is assumed to be a Lua statement and is executed.
-.LP
-Options start with
-.B '\-'
-and are described below.
-You can use
-.B "'\--'"
-to signal the end of options.
-.LP
-If no arguments are given,
-then
-.B "\-v \-i"
-is assumed when the standard input is a terminal;
-otherwise,
-.B "\-"
-is assumed.
-.LP
-In interactive mode,
-.B lua
-prompts the user,
-reads lines from the standard input,
-and executes them as they are read.
-If a line does not contain a complete statement,
-then a secondary prompt is displayed and
-lines are read until a complete statement is formed or
-a syntax error is found.
-So, one way to interrupt the reading of an incomplete statement is
-to force a syntax error:
-adding a
-.B ';'
-in the middle of a statement is a sure way of forcing a syntax error
-(except inside multiline strings and comments; these must be closed explicitly).
-If a line starts with
-.BR '=' ,
-then
-.B lua
-displays the values of all the expressions in the remainder of the
-line. The expressions must be separated by commas.
-The primary prompt is the value of the global variable
-.BR _PROMPT ,
-if this value is a string;
-otherwise, the default prompt is used.
-Similarly, the secondary prompt is the value of the global variable
-.BR _PROMPT2 .
-So,
-to change the prompts,
-set the corresponding variable to a string of your choice.
-You can do that after calling the interpreter
-or on the command line
-(but in this case you have to be careful with quotes
-if the prompt string contains a space; otherwise you may confuse the shell.)
-The default prompts are "> " and ">> ".
-.SH OPTIONS
-.TP
-.B \-
-load and execute the standard input as a file,
-that is,
-not interactively,
-even when the standard input is a terminal.
-.TP
-.BI \-e " stat"
-execute statement
-.IR stat .
-You need to quote
-.I stat
-if it contains spaces, quotes,
-or other characters special to the shell.
-.TP
-.B \-i
-enter interactive mode after
-.I script
-is executed.
-.TP
-.BI \-l " name"
-call
-.BI require(' name ')
-before executing
-.IR script .
-Typically used to load libraries.
-.TP
-.B \-v
-show version information.
-.SH "SEE ALSO"
-.BR luac (1)
-.br
-http://www.lua.org/
-.SH DIAGNOSTICS
-Error messages should be self explanatory.
-.SH AUTHORS
-R. Ierusalimschy,
-L. H. de Figueiredo,
-and
-W. Celes
-.\" EOF
diff --git a/engines/sword25/util/lua/doc/lua.css b/engines/sword25/util/lua/doc/lua.css
deleted file mode 100755
index 039cf11698..0000000000
--- a/engines/sword25/util/lua/doc/lua.css
+++ /dev/null
@@ -1,41 +0,0 @@
-body {
- color: #000000 ;
- background-color: #FFFFFF ;
- font-family: sans-serif ;
- text-align: justify ;
- margin-right: 20px ;
- margin-left: 20px ;
-}
-
-h1, h2, h3, h4 {
- font-weight: normal ;
- font-style: italic ;
-}
-
-a:link {
- color: #000080 ;
- background-color: inherit ;
- text-decoration: none ;
-}
-
-a:visited {
- background-color: inherit ;
- text-decoration: none ;
-}
-
-a:link:hover, a:visited:hover {
- color: #000080 ;
- background-color: #E0E0FF ;
-}
-
-a:link:active, a:visited:active {
- color: #FF0000 ;
-}
-
-hr {
- border: 0 ;
- height: 1px ;
- color: #a0a0a0 ;
- background-color: #a0a0a0 ;
-}
-
diff --git a/engines/sword25/util/lua/doc/lua.html b/engines/sword25/util/lua/doc/lua.html
deleted file mode 100755
index 1d435ab029..0000000000
--- a/engines/sword25/util/lua/doc/lua.html
+++ /dev/null
@@ -1,172 +0,0 @@
-
-
-
-NAME
-lua - Lua interpreter
-SYNOPSIS
-lua
-[
-options
-]
-[
-script
-[
-args
-]
-]
-DESCRIPTION
-lua
-is the stand-alone Lua interpreter.
-It loads and executes Lua programs,
-either in textual source form or
-in precompiled binary form.
-(Precompiled binaries are output by
-luac,
-the Lua compiler.)
-lua
-can be used as a batch interpreter and also interactively.
-OPTIONS
-SEE ALSO
-luac(1)
-
-http://www.lua.org/
-DIAGNOSTICS
-Error messages should be self explanatory.
-AUTHORS
-R. Ierusalimschy,
-L. H. de Figueiredo,
-and
-W. Celes
-
-
-
diff --git a/engines/sword25/util/lua/doc/luac.1 b/engines/sword25/util/lua/doc/luac.1
deleted file mode 100755
index d8146782df..0000000000
--- a/engines/sword25/util/lua/doc/luac.1
+++ /dev/null
@@ -1,136 +0,0 @@
-.\" $Id: luac.man,v 1.28 2006/01/06 16:03:34 lhf Exp $
-.TH LUAC 1 "$Date: 2006/01/06 16:03:34 $"
-.SH NAME
-luac \- Lua compiler
-.SH SYNOPSIS
-.B luac
-[
-.I options
-] [
-.I filenames
-]
-.SH DESCRIPTION
-.B luac
-is the Lua compiler.
-It translates programs written in the Lua programming language
-into binary files that can be later loaded and executed.
-.LP
-The main advantages of precompiling chunks are:
-faster loading,
-protecting source code from accidental user changes,
-and
-off-line syntax checking.
-.LP
-Pre-compiling does not imply faster execution
-because in Lua chunks are always compiled into bytecodes before being executed.
-.B luac
-simply allows those bytecodes to be saved in a file for later execution.
-.LP
-Pre-compiled chunks are not necessarily smaller than the corresponding source.
-The main goal in pre-compiling is faster loading.
-.LP
-The binary files created by
-.B luac
-are portable only among architectures with the same word size and byte order.
-.LP
-.B luac
-produces a single output file containing the bytecodes
-for all source files given.
-By default,
-the output file is named
-.BR luac.out ,
-but you can change this with the
-.B \-o
-option.
-.LP
-In the command line,
-you can mix
-text files containing Lua source and
-binary files containing precompiled chunks.
-This is useful to combine several precompiled chunks,
-even from different (but compatible) platforms,
-into a single precompiled chunk.
-.LP
-You can use
-.B "'\-'"
-to indicate the standard input as a source file
-and
-.B "'\--'"
-to signal the end of options
-(that is,
-all remaining arguments will be treated as files even if they start with
-.BR "'\-'" ).
-.LP
-The internal format of the binary files produced by
-.B luac
-is likely to change when a new version of Lua is released.
-So,
-save the source files of all Lua programs that you precompile.
-.LP
-.SH OPTIONS
-Options must be separate.
-.TP
-.B \-l
-produce a listing of the compiled bytecode for Lua's virtual machine.
-Listing bytecodes is useful to learn about Lua's virtual machine.
-If no files are given, then
-.B luac
-loads
-.B luac.out
-and lists its contents.
-.TP
-.BI \-o " file"
-output to
-.IR file ,
-instead of the default
-.BR luac.out .
-(You can use
-.B "'\-'"
-for standard output,
-but not on platforms that open standard output in text mode.)
-The output file may be a source file because
-all files are loaded before the output file is written.
-Be careful not to overwrite precious files.
-.TP
-.B \-p
-load files but do not generate any output file.
-Used mainly for syntax checking and for testing precompiled chunks:
-corrupted files will probably generate errors when loaded.
-Lua always performs a thorough integrity test on precompiled chunks.
-Bytecode that passes this test is completely safe,
-in the sense that it will not break the interpreter.
-However,
-there is no guarantee that such code does anything sensible.
-(None can be given, because the halting problem is unsolvable.)
-If no files are given, then
-.B luac
-loads
-.B luac.out
-and tests its contents.
-No messages are displayed if the file passes the integrity test.
-.TP
-.B \-s
-strip debug information before writing the output file.
-This saves some space in very large chunks,
-but if errors occur when running a stripped chunk,
-then the error messages may not contain the full information they usually do.
-For instance,
-line numbers and names of local variables are lost.
-.TP
-.B \-v
-show version information.
-.SH FILES
-.TP 15
-.B luac.out
-default output file
-.SH "SEE ALSO"
-.BR lua (1)
-.br
-http://www.lua.org/
-.SH DIAGNOSTICS
-Error messages should be self explanatory.
-.SH AUTHORS
-L. H. de Figueiredo,
-R. Ierusalimschy and
-W. Celes
-.\" EOF
diff --git a/engines/sword25/util/lua/doc/luac.html b/engines/sword25/util/lua/doc/luac.html
deleted file mode 100755
index 179ffe8288..0000000000
--- a/engines/sword25/util/lua/doc/luac.html
+++ /dev/null
@@ -1,145 +0,0 @@
-
-
-
-NAME
-luac - Lua compiler
-SYNOPSIS
-luac
-[
-options
-] [
-filenames
-]
-DESCRIPTION
-luac
-is the Lua compiler.
-It translates programs written in the Lua programming language
-into binary files that can be later loaded and executed.
-OPTIONS
-Options must be separate.
-FILES
-SEE ALSO
-lua(1)
-
-http://www.lua.org/
-DIAGNOSTICS
-Error messages should be self explanatory.
-AUTHORS
-L. H. de Figueiredo,
-R. Ierusalimschy and
-W. Celes
-
-
-
diff --git a/engines/sword25/util/lua/doc/manual.css b/engines/sword25/util/lua/doc/manual.css
deleted file mode 100755
index eed5afd9ee..0000000000
--- a/engines/sword25/util/lua/doc/manual.css
+++ /dev/null
@@ -1,13 +0,0 @@
-h3 code {
- font-family: inherit ;
-}
-
-pre {
- font-size: 105% ;
-}
-
-span.apii {
- float: right ;
- font-family: inherit ;
-}
-
diff --git a/engines/sword25/util/lua/doc/manual.html b/engines/sword25/util/lua/doc/manual.html
deleted file mode 100755
index b125c13d88..0000000000
--- a/engines/sword25/util/lua/doc/manual.html
+++ /dev/null
@@ -1,8764 +0,0 @@
-
-
-
-
-
-
-
-
-by Roberto Ierusalimschy, Luiz Henrique de Figueiredo, Waldemar Celes
-
-Lua 5.1 Reference Manual
-
-1 - Introduction
-
-lua,
-which uses the Lua library to offer a complete, stand-alone Lua interpreter.
-
-
-www.lua.org.
-
-
-2 - The Language
-
-2.1 - Lexical Conventions
-
-
- and break do else elseif
- end false for function if
- in local nil not or
- repeat return then true until while
-
-
-and is a reserved word, but And and AND
-are two different, valid names.
-As a convention, names starting with an underscore followed by
-uppercase letters (such as _VERSION)
-are reserved for internal global variables used by Lua.
-
-
-
- + - * / % ^ #
- == ~= <= >= < > =
- ( ) { } [ ]
- ; : , . .. ...
-
-
-\a' (bell),
-'\b' (backspace),
-'\f' (form feed),
-'\n' (newline),
-'\r' (carriage return),
-'\t' (horizontal tab),
-'\v' (vertical tab),
-'\\' (backslash),
-'\"' (quotation mark [double quote]),
-and '\'' (apostrophe [single quote]).
-Moreover, a backslash followed by a real newline
-results in a newline in the string.
-A character in a string may also be specified by its numerical value
-using the escape sequence \ddd,
-where ddd is a sequence of up to three decimal digits.
-(Note that if a numerical escape is to be followed by a digit,
-it must be expressed using exactly three digits.)
-Strings in Lua may contain any 8-bit value, including embedded zeros,
-which can be specified as '\0'.
-
-
-[[,
-an opening long bracket of level 1 is written as [=[,
-and so on.
-A closing long bracket is defined similarly;
-for instance, a closing long bracket of level 4 is written as ]====].
-A long string starts with an opening long bracket of any level and
-ends at the first closing long bracket of the same level.
-Literals in this bracketed form may run for several lines,
-do not interpret any escape sequences,
-and ignore long brackets of any other level.
-They may contain anything except a closing bracket of the proper level.
-
-
-a' is coded as 97,
-newline is coded as 10, and '1' is coded as 49),
-the five literals below denote the same string:
-
-
- a = 'alo\n123"'
- a = "alo\n123\""
- a = '\97lo\10\04923"'
- a = [[alo
- 123"]]
- a = [==[
- alo
- 123"]==]
-
-
-0x.
-Examples of valid numerical constants are
-
-
- 3 3.0 3.1416 314.16e-2 0.31416E1 0xff 0x56
-
-
---)
-anywhere outside a string.
-If the text immediately after -- is not an opening long bracket,
-the comment is a short comment,
-which runs until the end of the line.
-Otherwise, it is a long comment,
-which runs until the corresponding closing long bracket.
-Long comments are frequently used to disable code temporarily.
-
-
-
-
-
-2.2 - Values and Types
-
-luaconf.h.)
-String represents arrays of characters.
-
-Lua is 8-bit clean:
-strings may contain any 8-bit character,
-including embedded zeros ('\0') (see §2.1).
-
-
-a.name as syntactic sugar for a["name"].
-There are several convenient ways to create tables in Lua
-(see §2.5.7).
-
-
-type returns a string describing the type
-of a given value.
-
-
-
-2.2.1 - Coercion
-
-format function from the string library
-(see string.format).
-
-
-
-
-
-
-
-2.3 - Variables
-
-
- var ::= Name
-
- var ::= prefixexp `[´ exp `]´
-
t[i] is equivalent to
-a call gettable_event(t,i).
-(See §2.8 for a complete description of the
-gettable_event function.
-This function is not defined or callable in Lua.
-We use it here only for explanatory purposes.)
-
-
-var.Name is just syntactic sugar for
-var["Name"]:
-
-
- var ::= prefixexp `.´ Name
-
-
-getfenv.
-To replace it,
-you call setfenv.
-(You can only manipulate the environment of C functions
-through the debug library; (see §5.9).)
-
-
-x
-is equivalent to _env.x,
-which in turn is equivalent to
-
-
- gettable_event(_env, "x")
-
_env is the environment of the running function.
-(See §2.8 for a complete description of the
-gettable_event function.
-This function is not defined or callable in Lua.
-Similarly, the _env variable is not defined in Lua.
-We use them here only for explanatory purposes.)
-
-
-
-
-
-2.4 - Statements
-
-2.4.1 - Chunks
-
-
- chunk ::= {stat [`;´]}
-;;' is not legal.
-
-
-luac for details.
-Programs in source and compiled forms are interchangeable;
-Lua automatically detects the file type and acts accordingly.
-
-
-
-
-
-
-2.4.2 - Blocks
- block ::= chunk
-
-
-
- stat ::= do block end
-
2.4.3 - Assignment
-
-
- stat ::= varlist `=´ explist
- varlist ::= var {`,´ var}
- explist ::= exp {`,´ exp}
-
- i = 3
- i, a[i] = i+1, 20
-
a[3] to 20, without affecting a[4]
-because the i in a[i] is evaluated (to 3)
-before it is assigned 4.
-Similarly, the line
-
-
- x, y = y, x
-
x and y.
-
-
-t[i] = val is equivalent to
-settable_event(t,i,val).
-(See §2.8 for a complete description of the
-settable_event function.
-This function is not defined or callable in Lua.
-We use it here only for explanatory purposes.)
-
-
-x = val
-is equivalent to the assignment
-_env.x = val,
-which in turn is equivalent to
-
-
- settable_event(_env, "x", val)
-
_env is the environment of the running function.
-(The _env variable is not defined in Lua.
-We use it here only for explanatory purposes.)
-
-
-
-
-
-2.4.4 - Control Structures
- stat ::= while exp do block end
- stat ::= repeat block until exp
- stat ::= if exp then block {elseif exp then block} [else block] end
-
- stat ::= return [explist]
-
-
-
- stat ::= break
-
do return end and do break end,
-because now return and break are the last statements in
-their (inner) blocks.
-
-
-
-
-
-2.4.5 - For Statement
-
-
- stat ::= for Name `=´ exp `,´ exp [`,´ exp] do block end
-
- for v = e1, e2, e3 do block end
-
- do
- local var, limit, step = tonumber(e1), tonumber(e2), tonumber(e3)
- if not (var and limit and step) then error() end
- while (step > 0 and var <= limit) or (step <= 0 and var >= limit) do
- local v = var
- block
- var = var + step
- end
- end
-
-
-
-
-var, limit, and step are invisible variables.
-The names are here for explanatory purposes only.
-v is local to the loop;
-you cannot use its value after the for ends or is broken.
-If you need this value,
-assign it to another variable before breaking or exiting the loop.
-
- stat ::= for namelist in explist do block end
- namelist ::= Name {`,´ Name}
-
- for var_1, ···, var_n in explist do block end
-
- do
- local f, s, var = explist
- while true do
- local var_1, ···, var_n = f(s, var)
- var = var_1
- if var == nil then break end
- block
- end
- end
-
-
-
-
-
-
-
-explist is evaluated only once.
-Its results are an iterator function,
-a state,
-and an initial value for the first iterator variable.
-f, s, and var are invisible variables.
-The names are here for explanatory purposes only.
-var_i are local to the loop;
-you cannot use their values after the for ends.
-If you need these values,
-then assign them to other variables before breaking or exiting the loop.
-2.4.6 - Function Calls as Statements
- stat ::= functioncall
-
2.4.7 - Local Declarations
- stat ::= local namelist [`=´ explist]
-
2.5 - Expressions
-
-
- exp ::= prefixexp
- exp ::= nil | false | true
- exp ::= Number
- exp ::= String
- exp ::= function
- exp ::= tableconstructor
- exp ::= `...´
- exp ::= exp binop exp
- exp ::= unop exp
- prefixexp ::= var | functioncall | `(´ exp `)´
-
-
-...'), can only be used when
-directly inside a vararg function;
-they are explained in §2.5.9.
-
-
-
- f() -- adjusted to 0 results
- g(f(), x) -- f() is adjusted to 1 result
- g(x, f()) -- g gets x plus all results from f()
- a,b,c = f(), x -- f() is adjusted to 1 result (c gets nil)
- a,b = ... -- a gets the first vararg parameter, b gets
- -- the second (both a and b may get nil if there
- -- is no corresponding vararg parameter)
-
- a,b,c = x, f() -- f() is adjusted to 2 results
- a,b,c = f() -- f() is adjusted to 3 results
- return f() -- returns all results from f()
- return ... -- returns all received vararg parameters
- return x,y,f() -- returns x, y, and all results from f()
- {f()} -- creates a list with all results from f()
- {...} -- creates a list with all vararg parameters
- {f(), nil} -- f() is adjusted to 1 result
-
-
-(f(x,y,z)) is always a single value,
-even if f returns several values.
-(The value of (f(x,y,z)) is the first value returned by f
-or nil if f does not return any values.)
-
-
-
-2.5.1 - Arithmetic Operators
+ (addition),
-- (subtraction), * (multiplication),
-/ (division), % (modulo), and ^ (exponentiation);
-and unary - (negation).
-If the operands are numbers, or strings that can be converted to
-numbers (see §2.2.1),
-then all operations have the usual meaning.
-Exponentiation works for any exponent.
-For instance, x^(-0.5) computes the inverse of the square root of x.
-Modulo is defined as
-
-
- a % b == a - math.floor(a/b)*b
-
2.5.2 - Relational Operators
- == ~= < > <= >=
-
==) first compares the type of its operands.
-If the types are different, then the result is false.
-Otherwise, the values of the operands are compared.
-Numbers and strings are compared in the usual way.
-Objects (tables, userdata, threads, and functions)
-are compared by reference:
-two objects are considered equal only if they are the same object.
-Every time you create a new object
-(a table, userdata, thread, or function),
-this new object is different from any previously existing object.
-
-
-"0"==0 evaluates to false,
-and t[0] and t["0"] denote different
-entries in a table.
-
-
-~= is exactly the negation of equality (==).
-
-
-2.5.3 - Logical Operators
- 10 or 20 --> 10
- 10 or error() --> 10
- nil or "a" --> "a"
- nil and 10 --> nil
- false and error() --> false
- false and nil --> false
- false or nil --> nil
- 10 and 20 --> 20
-
2.5.4 - Concatenation
..').
-If both operands are strings or numbers, then they are converted to
-strings according to the rules mentioned in §2.2.1.
-Otherwise, the "concat" metamethod is called (see §2.8).
-
-
-
-
-
-2.5.5 - The Length Operator
-
-#.
-The length of a string is its number of bytes
-(that is, the usual meaning of string length when each
-character is one byte).
-
-
-t is defined to be any
-integer index n
-such that t[n] is not nil and t[n+1] is nil;
-moreover, if t[1] is nil, n may be zero.
-For a regular array, with non-nil values from 1 to a given n,
-its length is exactly that n,
-the index of its last value.
-If the array has "holes"
-(that is, nil values between other non-nil values),
-then #t may be any of the indices that
-directly precedes a nil value
-(that is, it may consider any such nil value as the end of
-the array).
-
-
-
-
-
-2.5.6 - Precedence
- or
- and
- < > <= >= ~= ==
- ..
- + -
- * / %
- not # - (unary)
- ^
-
..') and exponentiation ('^')
-operators are right associative.
-All other binary operators are left associative.
-
-
-
-
-
-2.5.7 - Table Constructors
- tableconstructor ::= `{´ [fieldlist] `}´
- fieldlist ::= field {fieldsep field} [fieldsep]
- field ::= `[´ exp `]´ `=´ exp | Name `=´ exp | exp
- fieldsep ::= `,´ | `;´
-
-
-[exp1] = exp2 adds to the new table an entry
-with key exp1 and value exp2.
-A field of the form name = exp is equivalent to
-["name"] = exp.
-Finally, fields of the form exp are equivalent to
-[i] = exp, where i are consecutive numerical integers,
-starting with 1.
-Fields in the other formats do not affect this counting.
-For example,
-
-
- a = { [f(1)] = g; "x", "y"; x = 1, f(x), [30] = 23; 45 }
-
- do
- local t = {}
- t[f(1)] = g
- t[1] = "x" -- 1st exp
- t[2] = "y" -- 2nd exp
- t.x = 1 -- t["x"] = 1
- t[3] = f(x) -- 3rd exp
- t[30] = 23
- t[4] = 45 -- 4th exp
- a = t
- end
-
-
-exp
-and the expression is a function call or a vararg expression,
-then all values returned by this expression enter the list consecutively
-(see §2.5.8).
-To avoid this,
-enclose the function call (or the vararg expression)
-in parentheses (see §2.5).
-
-
-2.5.8 - Function Calls
- functioncall ::= prefixexp args
-
- functioncall ::= prefixexp `:´ Name args
-
v:name(args)
-is syntactic sugar for v.name(v,args),
-except that v is evaluated only once.
-
-
-
- args ::= `(´ [explist] `)´
- args ::= tableconstructor
- args ::= String
-
f{fields} is
-syntactic sugar for f({fields});
-that is, the argument list is a single new table.
-A call of the form f'string'
-(or f"string" or f[[string]])
-is syntactic sugar for f('string');
-that is, the argument list is a single literal string.
-
-
-(' in a function call.
-This restriction avoids some ambiguities in the language.
-If you write
-
-
- a = f
- (g).x(a)
-
a = f(g).x(a).
-So, if you want two statements, you must add a semi-colon between them.
-If you actually want to call f,
-you must remove the line break before (g).
-
-
-return functioncall is called
-a tail call.
-Lua implements proper tail calls
-(or proper tail recursion):
-in a tail call,
-the called function reuses the stack entry of the calling function.
-Therefore, there is no limit on the number of nested tail calls that
-a program can execute.
-However, a tail call erases any debug information about the
-calling function.
-Note that a tail call only happens with a particular syntax,
-where the return has one single function call as argument;
-this syntax makes the calling function return exactly
-the returns of the called function.
-So, none of the following examples are tail calls:
-
-
- return (f(x)) -- results adjusted to 1
- return 2 * f(x)
- return x, f(x) -- additional results
- f(x); return -- results discarded
- return x or f(x) -- results adjusted to 1
-
-
-
-
-
-2.5.9 - Function Definitions
-
-
- function ::= function funcbody
- funcbody ::= `(´ [parlist] `)´ block end
-
-
-
- stat ::= function funcname funcbody
- stat ::= local function Name funcbody
- funcname ::= Name {`.´ Name} [`:´ Name]
-
- function f () body end
-
- f = function () body end
-
- function t.a.b.c.f () body end
-
- t.a.b.c.f = function () body end
-
- local function f () body end
-
- local f; f = function () body end
-
- local f = function () body end
-
f.)
-
-
-
- parlist ::= namelist [`,´ `...´] | `...´
-
...') at the end of its parameter list.
-A vararg function does not adjust its argument list;
-instead, it collects all extra arguments and supplies them
-to the function through a vararg expression,
-which is also written as three dots.
-The value of this expression is a list of all actual extra arguments,
-similar to a function with multiple results.
-If a vararg expression is used inside another expression
-or in the middle of a list of expressions,
-then its return list is adjusted to one element.
-If the expression is used as the last element of a list of expressions,
-then no adjustment is made
-(unless the call is enclosed in parentheses).
-
-
-
- function f(a, b) end
- function g(a, b, ...) end
- function r() return 1,2,3 end
-
- CALL PARAMETERS
-
- f(3) a=3, b=nil
- f(3, 4) a=3, b=4
- f(3, 4, 5) a=3, b=4
- f(r(), 10) a=1, b=10
- f(r()) a=1, b=2
-
- g(3) a=3, b=nil, ... --> (nothing)
- g(3, 4) a=3, b=4, ... --> (nothing)
- g(3, 4, 5, 8) a=3, b=4, ... --> 5 8
- g(5, r()) a=5, b=1, ... --> 2 3
-
-
-self.
-Thus, the statement
-
-
- function t.a.b.c:f (params) body end
-
- t.a.b.c.f = function (self, params) body end
-
-
-
-
-
-
-
-2.6 - Visibility Rules
-
-
- x = 10 -- global variable
- do -- new block
- local x = x -- new 'x', with value 10
- print(x) --> 10
- x = x+1
- do -- another block
- local x = x+1 -- another 'x'
- print(x) --> 12
- end
- print(x) --> 11
- end
- print(x) --> 10 (the global one)
-
-
-local x = x,
-the new x being declared is not in scope yet,
-and so the second x refers to the outside variable.
-
-
-
- a = {}
- local x = 20
- for i=1,10 do
- local y = 0
- a[i] = function () y=y+1; return x+y end
- end
-y variable,
-while all of them share the same x.
-
-
-
-
-
-2.7 - Error Handling
-
-lua_pcall).
-Whenever an error occurs during Lua compilation or execution,
-control returns to C,
-which can take appropriate measures
-(such as printing an error message).
-
-
-error function.
-If you need to catch errors in Lua,
-you can use the pcall function.
-
-
-
-
-
-2.8 - Metatables
-
-"__add" in its metatable.
-If it finds one,
-Lua calls this function to perform the addition.
-
-
-"add"
-and the metamethod is the function that performs the addition.
-
-
-getmetatable function.
-
-
-setmetatable
-function.
-You cannot change the metatable of other types from Lua
-(except using the debug library);
-you must use the C API for that.
-
-
-__';
-for instance, the key for operation "add" is the
-string "__add".
-The semantics of these operations is better explained by a Lua function
-describing how the interpreter executes the operation.
-
-
-rawget, tonumber, etc.)
-are described in §5.1.
-In particular, to retrieve the metamethod of a given object,
-we use the expression
-
-
- metatable(obj)[event]
-
- rawget(getmetatable(obj) or {}, event)
-
-
-
-
-
-
-
-+ operation.
-
-
-
-getbinhandler below defines how Lua chooses a handler
-for a binary operation.
-First, Lua tries the first operand.
-If its type does not define a handler for the operation,
-then Lua tries the second operand.
-
-
- function getbinhandler (op1, op2, event)
- return metatable(op1)[event] or metatable(op2)[event]
- end
-
op1 + op2 is
-
-
- function add_event (op1, op2)
- local o1, o2 = tonumber(op1), tonumber(op2)
- if o1 and o2 then -- both operands are numeric?
- return o1 + o2 -- '+' here is the primitive 'add'
- else -- at least one of the operands is not numeric
- local h = getbinhandler(op1, op2, "__add")
- if h then
- -- call the handler with both operands
- return (h(op1, op2))
- else -- no handler available: default behavior
- error(···)
- end
- end
- end
-
- operation.
-
-Behavior similar to the "add" operation.
-* operation.
-
-Behavior similar to the "add" operation.
-/ operation.
-
-Behavior similar to the "add" operation.
-% operation.
-
-Behavior similar to the "add" operation,
-with the operation
-o1 - floor(o1/o2)*o2 as the primitive operation.
-^ (exponentiation) operation.
-
-Behavior similar to the "add" operation,
-with the function pow (from the C math library)
-as the primitive operation.
-- operation.
-
-
-
- function unm_event (op)
- local o = tonumber(op)
- if o then -- operand is numeric?
- return -o -- '-' here is the primitive 'unm'
- else -- the operand is not numeric.
- -- Try to get a handler from the operand
- local h = metatable(op).__unm
- if h then
- -- call the handler with the operand
- return (h(op))
- else -- no handler available: default behavior
- error(···)
- end
- end
- end
-
.. (concatenation) operation.
-
-
-
- function concat_event (op1, op2)
- if (type(op1) == "string" or type(op1) == "number") and
- (type(op2) == "string" or type(op2) == "number") then
- return op1 .. op2 -- primitive string concatenation
- else
- local h = getbinhandler(op1, op2, "__concat")
- if h then
- return (h(op1, op2))
- else
- error(···)
- end
- end
- end
-
# operation.
-
-
-
- function len_event (op)
- if type(op) == "string" then
- return strlen(op) -- primitive string length
- elseif type(op) == "table" then
- return #op -- primitive table length
- else
- local h = metatable(op).__len
- if h then
- -- call the handler with the operand
- return (h(op))
- else -- no handler available: default behavior
- error(···)
- end
- end
- end
-
== operation.
-
-The function getcomphandler defines how Lua chooses a metamethod
-for comparison operators.
-A metamethod only is selected when both objects
-being compared have the same type
-and the same metamethod for the selected operation.
-
-
- function getcomphandler (op1, op2, event)
- if type(op1) ~= type(op2) then return nil end
- local mm1 = metatable(op1)[event]
- local mm2 = metatable(op2)[event]
- if mm1 == mm2 then return mm1 else return nil end
- end
-
- function eq_event (op1, op2)
- if type(op1) ~= type(op2) then -- different types?
- return false -- different objects
- end
- if op1 == op2 then -- primitive equal?
- return true -- objects are equal
- end
- -- try metamethod
- local h = getcomphandler(op1, op2, "__eq")
- if h then
- return (h(op1, op2))
- else
- return false
- end
- end
-
a ~= b is equivalent to not (a == b).
-< operation.
-
-
-
- function lt_event (op1, op2)
- if type(op1) == "number" and type(op2) == "number" then
- return op1 < op2 -- numeric comparison
- elseif type(op1) == "string" and type(op2) == "string" then
- return op1 < op2 -- lexicographic comparison
- else
- local h = getcomphandler(op1, op2, "__lt")
- if h then
- return (h(op1, op2))
- else
- error(···);
- end
- end
- end
-
a > b is equivalent to b < a.
-<= operation.
-
-
-
- function le_event (op1, op2)
- if type(op1) == "number" and type(op2) == "number" then
- return op1 <= op2 -- numeric comparison
- elseif type(op1) == "string" and type(op2) == "string" then
- return op1 <= op2 -- lexicographic comparison
- else
- local h = getcomphandler(op1, op2, "__le")
- if h then
- return (h(op1, op2))
- else
- h = getcomphandler(op1, op2, "__lt")
- if h then
- return not h(op2, op1)
- else
- error(···);
- end
- end
- end
- end
-
a >= b is equivalent to b <= a.
-Note that, in the absence of a "le" metamethod,
-Lua tries the "lt", assuming that a <= b is
-equivalent to not (b < a).
-table[key].
-
-
-
- function gettable_event (table, key)
- local h
- if type(table) == "table" then
- local v = rawget(table, key)
- if v ~= nil then return v end
- h = metatable(table).__index
- if h == nil then return nil end
- else
- h = metatable(table).__index
- if h == nil then
- error(···);
- end
- end
- if type(h) == "function" then
- return (h(table, key)) -- call the handler
- else return h[key] -- or repeat operation on it
- end
- end
-
table[key] = value.
-
-
-
- function settable_event (table, key, value)
- local h
- if type(table) == "table" then
- local v = rawget(table, key)
- if v ~= nil then rawset(table, key, value); return end
- h = metatable(table).__newindex
- if h == nil then rawset(table, key, value); return end
- else
- h = metatable(table).__newindex
- if h == nil then
- error(···);
- end
- end
- if type(h) == "function" then
- h(table, key,value) -- call the handler
- else h[key] = value -- or repeat operation on it
- end
- end
-
- function function_event (func, ...)
- if type(func) == "function" then
- return func(...) -- primitive call
- else
- local h = metatable(func).__call
- if h then
- return h(func, ...)
- else
- error(···)
- end
- end
- end
-
2.9 - Environments
-
-loadfile, loadstring or load)
-and can be directly accessed by C code (see §3.3).
-
-
-setfenv.
-You can get the environment of a Lua function or the running thread
-by calling getfenv.
-To manipulate the environment of other objects
-(userdata, C functions, other threads) you must
-use the C API.
-
-
-
-
-
-2.10 - Garbage Collection
-
-lua_gc in C
-or collectgarbage in Lua.
-Both get percentage points as arguments
-(so an argument of 100 means a real value of 1).
-With these functions you can also control
-the collector directly (e.g., stop and restart it).
-
-
-
-2.10.1 - Garbage-Collection Metamethods
-
-__gc in their metatables are not
-collected immediately by the garbage collector.
-Instead, Lua puts them in a list.
-After the collection,
-Lua does the equivalent of the following function
-for each userdata in that list:
-
-
- function gc_event (udata)
- local h = metatable(udata).__gc
- if h then
- h(udata)
- end
- end
-
-
-2.10.2 - Weak Tables
-
-__mode field of its metatable.
-If the __mode field is a string containing the character 'k',
-the keys in the table are weak.
-If __mode contains 'v',
-the values in the table are weak.
-
-
-__mode.
-Otherwise, the weak behavior of the tables controlled by this
-metatable is undefined.
-
-
-
-
-
-
-
-2.11 - Coroutines
-
-coroutine.create.
-Its sole argument is a function
-that is the main function of the coroutine.
-The create function only creates a new coroutine and
-returns a handle to it (an object of type thread);
-it does not start the coroutine execution.
-
-
-coroutine.resume,
-passing as its first argument
-the thread returned by coroutine.create,
-the coroutine starts its execution,
-at the first line of its main function.
-Extra arguments passed to coroutine.resume are passed on
-to the coroutine main function.
-After the coroutine starts running,
-it runs until it terminates or yields.
-
-
-coroutine.resume returns true,
-plus any values returned by the coroutine main function.
-In case of errors, coroutine.resume returns false
-plus an error message.
-
-
-coroutine.yield.
-When a coroutine yields,
-the corresponding coroutine.resume returns immediately,
-even if the yield happens inside nested function calls
-(that is, not in the main function,
-but in a function directly or indirectly called by the main function).
-In the case of a yield, coroutine.resume also returns true,
-plus any values passed to coroutine.yield.
-The next time you resume the same coroutine,
-it continues its execution from the point where it yielded,
-with the call to coroutine.yield returning any extra
-arguments passed to coroutine.resume.
-
-
-coroutine.create,
-the coroutine.wrap function also creates a coroutine,
-but instead of returning the coroutine itself,
-it returns a function that, when called, resumes the coroutine.
-Any arguments passed to this function
-go as extra arguments to coroutine.resume.
-coroutine.wrap returns all the values returned by coroutine.resume,
-except the first one (the boolean error code).
-Unlike coroutine.resume,
-coroutine.wrap does not catch errors;
-any error is propagated to the caller.
-
-
-
- function foo (a)
- print("foo", a)
- return coroutine.yield(2*a)
- end
-
- co = coroutine.create(function (a,b)
- print("co-body", a, b)
- local r = foo(a+1)
- print("co-body", r)
- local r, s = coroutine.yield(a+b, a-b)
- print("co-body", r, s)
- return b, "end"
- end)
-
- print("main", coroutine.resume(co, 1, 10))
- print("main", coroutine.resume(co, "r"))
- print("main", coroutine.resume(co, "x", "y"))
- print("main", coroutine.resume(co, "x", "y"))
-
- co-body 1 10
- foo 2
-
- main true 4
- co-body r
- main true 11 -9
- co-body x y
- main true 10 end
- main false cannot resume dead coroutine
-
-
-
-
-
-3 - The Application Program Interface
-
-lua.h.
-
-
-luai_apicheck,
-in file luaconf.h.
-
-
-
-3.1 - The Stack
-
-lua_CFunction).
-
-
-1 ≤ abs(index) ≤ top).
-
-
-
-
-
-
-3.2 - Stack Size
-
-lua_checkstack
-to grow the stack size.
-
-
-LUA_MINSTACK stack positions are available.
-LUA_MINSTACK is defined as 20,
-so that usually you do not have to worry about stack space
-unless your code has loops pushing elements onto the stack.
-
-
-lua_checkstack.
-Such indices are called acceptable indices.
-More formally, we define an acceptable index
-as follows:
-
-
- (index < 0 && abs(index) <= top) ||
- (index > 0 && index <= stackspace)
-
3.3 - Pseudo-Indices
-
-LUA_GLOBALSINDEX.
-The environment of the running C function is always
-at pseudo-index LUA_ENVIRONINDEX.
-
-
-
- lua_getfield(L, LUA_GLOBALSINDEX, varname);
-
-
-
-
-
-3.4 - C Closures
-
-lua_pushcclosure).
-
-
-lua_upvalueindex.
-The first value associated with a function is at position
-lua_upvalueindex(1), and so on.
-Any access to lua_upvalueindex(n),
-where n is greater than the number of upvalues of the
-current function,
-produces an acceptable (but invalid) index.
-
-
-
-
-
-3.5 - Registry
-
-LUA_REGISTRYINDEX.
-Any C library can store data into this table,
-but it should take care to choose keys different from those used
-by other libraries, to avoid collisions.
-Typically, you should use as key a string containing your library name
-or a light userdata with the address of a C object in your code.
-
-
-3.6 - Error Handling in C
-
-longjmp facility to handle errors.
-(You can also choose to use exceptions if you use C++;
-see file luaconf.h.)
-When Lua faces any error
-(such as memory allocation errors, type errors, syntax errors,
-and runtime errors)
-it raises an error;
-that is, it does a long jump.
-A protected environment uses setjmp
-to set a recover point;
-any error jumps to the most recent active recover point.
-
-
-lua_error.
-
-
-
-
-
-3.7 - Functions and Types
-
-o,
-is how many elements the function pops from the stack.
-The second field, p,
-is how many elements the function pushes onto the stack.
-(Any function always pushes its results after popping its arguments.)
-A field in the form x|y means the function may push (or pop)
-x or y elements,
-depending on the situation;
-an interrogation mark '?' means that
-we cannot know how many elements the function pops/pushes
-by looking only at its arguments
-(e.g., they may depend on what is on the stack).
-The third field, x,
-tells whether the function may throw errors:
-'-' means the function never throws any error;
-'m' means the function may throw an error
-only due to not enough memory;
-'e' means the function may throw other kinds of errors;
-'v' means the function may throw an error on purpose.
-
-
-
-
-lua_Alloctypedef void * (*lua_Alloc) (void *ud,
- void *ptr,
- size_t osize,
- size_t nsize);
-
-realloc,
-but not exactly the same.
-Its arguments are
-ud, an opaque pointer passed to lua_newstate;
-ptr, a pointer to the block being allocated/reallocated/freed;
-osize, the original size of the block;
-nsize, the new size of the block.
-ptr is NULL if and only if osize is zero.
-When nsize is zero, the allocator must return NULL;
-if osize is not zero,
-it should free the block pointed to by ptr.
-When nsize is not zero, the allocator returns NULL
-if and only if it cannot fill the request.
-When nsize is not zero and osize is zero,
-the allocator should behave like malloc.
-When nsize and osize are not zero,
-the allocator behaves like realloc.
-Lua assumes that the allocator never fails when
-osize >= nsize.
-
-
-luaL_newstate.
-
-
- static void *l_alloc (void *ud, void *ptr, size_t osize,
- size_t nsize) {
- (void)ud; (void)osize; /* not used */
- if (nsize == 0) {
- free(ptr);
- return NULL;
- }
- else
- return realloc(ptr, nsize);
- }
-free(NULL) has no effect and that
-realloc(NULL, size) is equivalent to malloc(size).
-ANSI C ensures both behaviors.
-
-
-
-
-
-lua_atpaniclua_CFunction lua_atpanic (lua_State *L, lua_CFunction panicf);
-
-exit(EXIT_FAILURE),
-thus exiting the host application.
-Your panic function may avoid this exit by
-never returning (e.g., doing a long jump).
-
-
-lua_callvoid lua_call (lua_State *L, int nargs, int nresults);
-
-lua_call;
-nargs is the number of arguments that you pushed onto the stack.
-All arguments and the function value are popped from the stack
-when the function is called.
-The function results are pushed onto the stack when the function returns.
-The number of results is adjusted to nresults,
-unless nresults is LUA_MULTRET.
-In this case, all results from the function are pushed.
-Lua takes care that the returned values fit into the stack space.
-The function results are pushed onto the stack in direct order
-(the first result is pushed first),
-so that after the call the last result is on the top of the stack.
-
-
-longjmp).
-
-
-
- a = f("how", t.x, 14)
-
- lua_getfield(L, LUA_GLOBALSINDEX, "f"); /* function to be called */
- lua_pushstring(L, "how"); /* 1st argument */
- lua_getfield(L, LUA_GLOBALSINDEX, "t"); /* table to be indexed */
- lua_getfield(L, -1, "x"); /* push result of t.x (2nd arg) */
- lua_remove(L, -2); /* remove 't' from the stack */
- lua_pushinteger(L, 14); /* 3rd argument */
- lua_call(L, 3, 1); /* call 'f' with 3 arguments and 1 result */
- lua_setfield(L, LUA_GLOBALSINDEX, "a"); /* set global 'a' */
-
-lua_CFunctiontypedef int (*lua_CFunction) (lua_State *L);
-
-lua_gettop(L) returns the number of arguments received by the function.
-The first argument (if any) is at index 1
-and its last argument is at index lua_gettop(L).
-To return values to Lua, a C function just pushes them onto the stack,
-in direct order (the first result is pushed first),
-and returns the number of results.
-Any other value in the stack below the results will be properly
-discarded by Lua.
-Like a Lua function, a C function called by Lua can also return
-many results.
-
-
-
- static int foo (lua_State *L) {
- int n = lua_gettop(L); /* number of arguments */
- lua_Number sum = 0;
- int i;
- for (i = 1; i <= n; i++) {
- if (!lua_isnumber(L, i)) {
- lua_pushstring(L, "incorrect argument");
- lua_error(L);
- }
- sum += lua_tonumber(L, i);
- }
- lua_pushnumber(L, sum/n); /* first result */
- lua_pushnumber(L, sum); /* second result */
- return 2; /* number of results */
- }
-
-
-
-
-
-lua_checkstackint lua_checkstack (lua_State *L, int extra);
-
-extra free stack slots in the stack.
-It returns false if it cannot grow the stack to that size.
-This function never shrinks the stack;
-if the stack is already larger than the new size,
-it is left unchanged.
-
-
-
-
-
-lua_closevoid lua_close (lua_State *L);
-
-lua_concatvoid lua_concat (lua_State *L, int n);
-
-n values at the top of the stack,
-pops them, and leaves the result at the top.
-If n is 1, the result is the single value on the stack
-(that is, the function does nothing);
-if n is 0, the result is the empty string.
-Concatenation is performed following the usual semantics of Lua
-(see §2.5.4).
-
-
-
-
-
-lua_cpcallint lua_cpcall (lua_State *L, lua_CFunction func, void *ud);
-
-func in protected mode.
-func starts with only one element in its stack,
-a light userdata containing ud.
-In case of errors,
-lua_cpcall returns the same error codes as lua_pcall,
-plus the error object on the top of the stack;
-otherwise, it returns zero, and does not change the stack.
-All values returned by func are discarded.
-
-
-
-
-
-lua_createtablevoid lua_createtable (lua_State *L, int narr, int nrec);
-
-narr array elements and nrec non-array elements.
-This pre-allocation is useful when you know exactly how many elements
-the table will have.
-Otherwise you can use the function lua_newtable.
-
-
-
-
-
-lua_dumpint lua_dump (lua_State *L, lua_Writer writer, void *data);
-
-lua_dump calls function writer (see lua_Writer)
-with the given data
-to write them.
-
-
-lua_equalint lua_equal (lua_State *L, int index1, int index2);
-
-index1 and
-index2 are equal,
-following the semantics of the Lua == operator
-(that is, may call metamethods).
-Otherwise returns 0.
-Also returns 0 if any of the indices is non valid.
-
-
-
-
-
-lua_errorint lua_error (lua_State *L);
-
-luaL_error).
-
-
-
-
-
-lua_gcint lua_gc (lua_State *L, int what, int data);
-
-what:
-
-
-
-
-
-
-
-
-LUA_GCSTOP:
-stops the garbage collector.
-LUA_GCRESTART:
-restarts the garbage collector.
-LUA_GCCOLLECT:
-performs a full garbage-collection cycle.
-LUA_GCCOUNT:
-returns the current amount of memory (in Kbytes) in use by Lua.
-LUA_GCCOUNTB:
-returns the remainder of dividing the current amount of bytes of
-memory in use by Lua by 1024.
-LUA_GCSTEP:
-performs an incremental step of garbage collection.
-The step "size" is controlled by data
-(larger values mean more steps) in a non-specified way.
-If you want to control the step size
-you must experimentally tune the value of data.
-The function returns 1 if the step finished a
-garbage-collection cycle.
-LUA_GCSETPAUSE:
-sets data/100 as the new value
-for the pause of the collector (see §2.10).
-The function returns the previous value of the pause.
-LUA_GCSETSTEPMUL:
-sets data/100 as the new value for the step multiplier of
-the collector (see §2.10).
-The function returns the previous value of the step multiplier.
-lua_getallocflua_Alloc lua_getallocf (lua_State *L, void **ud);
-
-ud is not NULL, Lua stores in *ud the
-opaque pointer passed to lua_newstate.
-
-
-
-
-
-lua_getfenvvoid lua_getfenv (lua_State *L, int index);
-
-lua_getfieldvoid lua_getfield (lua_State *L, int index, const char *k);
-
-t[k],
-where t is the value at the given valid index.
-As in Lua, this function may trigger a metamethod
-for the "index" event (see §2.8).
-
-
-
-
-
-lua_getglobalvoid lua_getglobal (lua_State *L, const char *name);
-
-name.
-It is defined as a macro:
-
-
- #define lua_getglobal(L,s) lua_getfield(L, LUA_GLOBALSINDEX, s)
-
-
-
-
-
-lua_getmetatableint lua_getmetatable (lua_State *L, int index);
-
-lua_gettablevoid lua_gettable (lua_State *L, int index);
-
-t[k],
-where t is the value at the given valid index
-and k is the value at the top of the stack.
-
-
-lua_gettopint lua_gettop (lua_State *L);
-
-lua_insertvoid lua_insert (lua_State *L, int index);
-
-
-lua_Integertypedef ptrdiff_t lua_Integer;
-
-ptrdiff_t,
-which is usually the largest signed integral type the machine handles
-"comfortably".
-
-
-
-
-
-lua_isbooleanint lua_isboolean (lua_State *L, int index);
-
-lua_iscfunctionint lua_iscfunction (lua_State *L, int index);
-
-lua_isfunctionint lua_isfunction (lua_State *L, int index);
-
-lua_islightuserdataint lua_islightuserdata (lua_State *L, int index);
-
-lua_isnilint lua_isnil (lua_State *L, int index);
-
-lua_isnoneint lua_isnone (lua_State *L, int index);
-
-lua_isnoneornilint lua_isnoneornil (lua_State *L, int index);
-
-lua_isnumberint lua_isnumber (lua_State *L, int index);
-
-lua_isstringint lua_isstring (lua_State *L, int index);
-
-lua_istableint lua_istable (lua_State *L, int index);
-
-lua_isthreadint lua_isthread (lua_State *L, int index);
-
-lua_isuserdataint lua_isuserdata (lua_State *L, int index);
-
-lua_lessthanint lua_lessthan (lua_State *L, int index1, int index2);
-
-index1 is smaller
-than the value at acceptable index index2,
-following the semantics of the Lua < operator
-(that is, may call metamethods).
-Otherwise returns 0.
-Also returns 0 if any of the indices is non valid.
-
-
-
-
-
-lua_loadint lua_load (lua_State *L,
- lua_Reader reader,
- void *data,
- const char *chunkname);
-
-lua_load pushes the compiled chunk as a Lua
-function on top of the stack.
-Otherwise, it pushes an error message.
-The return values of lua_load are:
-
-
-
-
-
-LUA_ERRSYNTAX:
-syntax error during pre-compilation;LUA_ERRMEM:
-memory allocation error.lua_load automatically detects whether the chunk is text or binary,
-and loads it accordingly (see program luac).
-
-
-lua_load function uses a user-supplied reader function
-to read the chunk (see lua_Reader).
-The data argument is an opaque value passed to the reader function.
-
-
-chunkname argument gives a name to the chunk,
-which is used for error messages and in debug information (see §3.8).
-
-
-
-
-
-lua_newstatelua_State *lua_newstate (lua_Alloc f, void *ud);
-
-NULL if cannot create the state
-(due to lack of memory).
-The argument f is the allocator function;
-Lua does all memory allocation for this state through this function.
-The second argument, ud, is an opaque pointer that Lua
-simply passes to the allocator in every call.
-
-
-
-
-
-lua_newtablevoid lua_newtable (lua_State *L);
-
-lua_createtable(L, 0, 0).
-
-
-
-
-
-lua_newthreadlua_State *lua_newthread (lua_State *L);
-
-lua_State that represents this new thread.
-The new state returned by this function shares with the original state
-all global objects (such as tables),
-but has an independent execution stack.
-
-
-lua_newuserdatavoid *lua_newuserdata (lua_State *L, size_t size);
-
-gc metamethod,
-Lua calls the metamethod and marks the userdata as finalized.
-When this userdata is collected again then
-Lua frees its corresponding memory.
-
-
-
-
-
-lua_nextint lua_next (lua_State *L, int index);
-
-lua_next returns 0 (and pushes nothing).
-
-
-
- /* table is in the stack at index 't' */
- lua_pushnil(L); /* first key */
- while (lua_next(L, t) != 0) {
- /* uses 'key' (at index -2) and 'value' (at index -1) */
- printf("%s - %s\n",
- lua_typename(L, lua_type(L, -2)),
- lua_typename(L, lua_type(L, -1)));
- /* removes 'value'; keeps 'key' for next iteration */
- lua_pop(L, 1);
- }
-
-
-lua_tolstring directly on a key,
-unless you know that the key is actually a string.
-Recall that lua_tolstring changes
-the value at the given index;
-this confuses the next call to lua_next.
-
-
-
-
-
-
-lua_Numbertypedef double lua_Number;
-
-luaconf.h.
-
-
-lua_objlensize_t lua_objlen (lua_State *L, int index);
-
-#');
-for userdata, this is the size of the block of memory allocated
-for the userdata;
-for other values, it is 0.
-
-
-
-
-
-lua_pcallint lua_pcall (lua_State *L, int nargs, int nresults, int errfunc);
-
-nargs and nresults have the same meaning as
-in lua_call.
-If there are no errors during the call,
-lua_pcall behaves exactly like lua_call.
-However, if there is any error,
-lua_pcall catches it,
-pushes a single value on the stack (the error message),
-and returns an error code.
-Like lua_call,
-lua_pcall always removes the function
-and its arguments from the stack.
-
-
-errfunc is 0,
-then the error message returned on the stack
-is exactly the original error message.
-Otherwise, errfunc is the stack index of an
-error handler function.
-(In the current implementation, this index cannot be a pseudo-index.)
-In case of runtime errors,
-this function will be called with the error message
-and its return value will be the message returned on the stack by lua_pcall.
-
-
-lua_pcall,
-since by then the stack has unwound.
-
-
-lua_pcall function returns 0 in case of success
-or one of the following error codes
-(defined in lua.h):
-
-
-
-
-
-
-
-
-LUA_ERRRUN:
-a runtime error.
-LUA_ERRMEM:
-memory allocation error.
-For such errors, Lua does not call the error handler function.
-LUA_ERRERR:
-error while running the error handler function.
-lua_popvoid lua_pop (lua_State *L, int n);
-
-n elements from the stack.
-
-
-
-
-
-lua_pushbooleanvoid lua_pushboolean (lua_State *L, int b);
-
-b onto the stack.
-
-
-
-
-
-lua_pushcclosurevoid lua_pushcclosure (lua_State *L, lua_CFunction fn, int n);
-
-lua_pushcclosure
-is called to create and push the C function onto the stack,
-with the argument n telling how many values should be
-associated with the function.
-lua_pushcclosure also pops these values from the stack.
-
-
-
-
-
-lua_pushcfunctionvoid lua_pushcfunction (lua_State *L, lua_CFunction f);
-
-function that,
-when called, invokes the corresponding C function.
-
-
-lua_CFunction).
-
-
-lua_pushcfunction is defined as a macro:
-
-
- #define lua_pushcfunction(L,f) lua_pushcclosure(L,f,0)
-
-
-
-
-
-lua_pushfstringconst char *lua_pushfstring (lua_State *L, const char *fmt, ...);
-
-sprintf,
-but has some important differences:
-
-
-
-
-
-
-
-
-%%' (inserts a '%' in the string),
-'%s' (inserts a zero-terminated string, with no size restrictions),
-'%f' (inserts a lua_Number),
-'%p' (inserts a pointer as a hexadecimal numeral),
-'%d' (inserts an int), and
-'%c' (inserts an int as a character).
-lua_pushintegervoid lua_pushinteger (lua_State *L, lua_Integer n);
-
-n onto the stack.
-
-
-
-
-
-lua_pushlightuserdatavoid lua_pushlightuserdata (lua_State *L, void *p);
-
-lua_pushliteralvoid lua_pushliteral (lua_State *L, const char *s);
-
-lua_pushlstring,
-but can be used only when s is a literal string.
-In these cases, it automatically provides the string length.
-
-
-
-
-
-lua_pushlstringvoid lua_pushlstring (lua_State *L, const char *s, size_t len);
-
-s with size len
-onto the stack.
-Lua makes (or reuses) an internal copy of the given string,
-so the memory at s can be freed or reused immediately after
-the function returns.
-The string can contain embedded zeros.
-
-
-
-
-
-lua_pushnilvoid lua_pushnil (lua_State *L);
-
-lua_pushnumbervoid lua_pushnumber (lua_State *L, lua_Number n);
-
-n onto the stack.
-
-
-
-
-
-lua_pushstringvoid lua_pushstring (lua_State *L, const char *s);
-
-s
-onto the stack.
-Lua makes (or reuses) an internal copy of the given string,
-so the memory at s can be freed or reused immediately after
-the function returns.
-The string cannot contain embedded zeros;
-it is assumed to end at the first zero.
-
-
-
-
-
-lua_pushthreadint lua_pushthread (lua_State *L);
-
-L onto the stack.
-Returns 1 if this thread is the main thread of its state.
-
-
-
-
-
-lua_pushvaluevoid lua_pushvalue (lua_State *L, int index);
-
-lua_pushvfstringconst char *lua_pushvfstring (lua_State *L,
- const char *fmt,
- va_list argp);
-
-lua_pushfstring, except that it receives a va_list
-instead of a variable number of arguments.
-
-
-
-
-
-lua_rawequalint lua_rawequal (lua_State *L, int index1, int index2);
-
-index1 and
-index2 are primitively equal
-(that is, without calling metamethods).
-Otherwise returns 0.
-Also returns 0 if any of the indices are non valid.
-
-
-
-
-
-lua_rawgetvoid lua_rawget (lua_State *L, int index);
-
-lua_gettable, but does a raw access
-(i.e., without metamethods).
-
-
-
-
-
-lua_rawgetivoid lua_rawgeti (lua_State *L, int index, int n);
-
-t[n],
-where t is the value at the given valid index.
-The access is raw;
-that is, it does not invoke metamethods.
-
-
-
-
-
-lua_rawsetvoid lua_rawset (lua_State *L, int index);
-
-lua_settable, but does a raw assignment
-(i.e., without metamethods).
-
-
-
-
-
-lua_rawsetivoid lua_rawseti (lua_State *L, int index, int n);
-
-t[n] = v,
-where t is the value at the given valid index
-and v is the value at the top of the stack.
-
-
-
-lua_Readertypedef const char * (*lua_Reader) (lua_State *L,
- void *data,
- size_t *size);
-
-lua_load.
-Every time it needs another piece of the chunk,
-lua_load calls the reader,
-passing along its data parameter.
-The reader must return a pointer to a block of memory
-with a new piece of the chunk
-and set size to the block size.
-The block must exist until the reader function is called again.
-To signal the end of the chunk, the reader must return NULL.
-The reader function may return pieces of any size greater than zero.
-
-
-
-
-
-lua_registervoid lua_register (lua_State *L,
- const char *name,
- lua_CFunction f);
-
-f as the new value of global name.
-It is defined as a macro:
-
-
- #define lua_register(L,n,f) \
- (lua_pushcfunction(L, f), lua_setglobal(L, n))
-
-
-
-
-
-lua_removevoid lua_remove (lua_State *L, int index);
-
-lua_replacevoid lua_replace (lua_State *L, int index);
-
-lua_resumeint lua_resume (lua_State *L, int narg);
-
-lua_newthread);
-then you push onto its stack the main function plus any arguments;
-then you call lua_resume,
-with narg being the number of arguments.
-This call returns when the coroutine suspends or finishes its execution.
-When it returns, the stack contains all values passed to lua_yield,
-or all values returned by the body function.
-lua_resume returns
-LUA_YIELD if the coroutine yields,
-0 if the coroutine finishes its execution
-without errors,
-or an error code in case of errors (see lua_pcall).
-In case of errors,
-the stack is not unwound,
-so you can use the debug API over it.
-The error message is on the top of the stack.
-To restart a coroutine, you put on its stack only the values to
-be passed as results from yield,
-and then call lua_resume.
-
-
-
-
-
-lua_setallocfvoid lua_setallocf (lua_State *L, lua_Alloc f, void *ud);
-
-f
-with user data ud.
-
-
-
-
-
-lua_setfenvint lua_setfenv (lua_State *L, int index);
-
-lua_setfenv returns 0.
-Otherwise it returns 1.
-
-
-
-
-
-lua_setfieldvoid lua_setfield (lua_State *L, int index, const char *k);
-
-t[k] = v,
-where t is the value at the given valid index
-and v is the value at the top of the stack.
-
-
-lua_setglobalvoid lua_setglobal (lua_State *L, const char *name);
-
-name.
-It is defined as a macro:
-
-
- #define lua_setglobal(L,s) lua_setfield(L, LUA_GLOBALSINDEX, s)
-
-
-
-
-
-lua_setmetatableint lua_setmetatable (lua_State *L, int index);
-
-lua_settablevoid lua_settable (lua_State *L, int index);
-
-t[k] = v,
-where t is the value at the given valid index,
-v is the value at the top of the stack,
-and k is the value just below the top.
-
-
-lua_settopvoid lua_settop (lua_State *L, int index);
-
-index is 0, then all stack elements are removed.
-
-
-
-
-
-
-lua_Statetypedef struct lua_State lua_State;
-
-lua_newstate,
-which creates a Lua state from scratch.
-
-
-
-
-
-lua_statusint lua_status (lua_State *L);
-
-L.
-
-
-LUA_YIELD if the thread is suspended.
-
-
-
-
-
-lua_tobooleanint lua_toboolean (lua_State *L, int index);
-
-lua_toboolean returns 1 for any Lua value
-different from false and nil;
-otherwise it returns 0.
-It also returns 0 when called with a non-valid index.
-(If you want to accept only actual boolean values,
-use lua_isboolean to test the value's type.)
-
-
-
-
-
-lua_tocfunctionlua_CFunction lua_tocfunction (lua_State *L, int index);
-
-NULL.
-
-
-
-
-
-lua_tointegerlua_Integer lua_tointeger (lua_State *L, int index);
-
-lua_Integer.
-The Lua value must be a number or a string convertible to a number
-(see §2.2.1);
-otherwise, lua_tointeger returns 0.
-
-
-lua_tolstringconst char *lua_tolstring (lua_State *L, int index, size_t *len);
-
-len is not NULL,
-it also sets *len with the string length.
-The Lua value must be a string or a number;
-otherwise, the function returns NULL.
-If the value is a number,
-then lua_tolstring also
-changes the actual value in the stack to a string.
-(This change confuses lua_next
-when lua_tolstring is applied to keys during a table traversal.)
-
-
-lua_tolstring returns a fully aligned pointer
-to a string inside the Lua state.
-This string always has a zero ('\0')
-after its last character (as in C),
-but may contain other zeros in its body.
-Because Lua has garbage collection,
-there is no guarantee that the pointer returned by lua_tolstring
-will be valid after the corresponding value is removed from the stack.
-
-
-
-
-
-lua_tonumberlua_Number lua_tonumber (lua_State *L, int index);
-
-lua_Number (see lua_Number).
-The Lua value must be a number or a string convertible to a number
-(see §2.2.1);
-otherwise, lua_tonumber returns 0.
-
-
-
-
-
-lua_topointerconst void *lua_topointer (lua_State *L, int index);
-
-void*).
-The value may be a userdata, a table, a thread, or a function;
-otherwise, lua_topointer returns NULL.
-Different objects will give different pointers.
-There is no way to convert the pointer back to its original value.
-
-
-lua_tostringconst char *lua_tostring (lua_State *L, int index);
-
-lua_tolstring with len equal to NULL.
-
-
-
-
-
-lua_tothreadlua_State *lua_tothread (lua_State *L, int index);
-
-lua_State*).
-This value must be a thread;
-otherwise, the function returns NULL.
-
-
-
-
-
-lua_touserdatavoid *lua_touserdata (lua_State *L, int index);
-
-NULL.
-
-
-
-
-
-lua_typeint lua_type (lua_State *L, int index);
-
-LUA_TNONE for a non-valid index
-(that is, an index to an "empty" stack position).
-The types returned by lua_type are coded by the following constants
-defined in lua.h:
-LUA_TNIL,
-LUA_TNUMBER,
-LUA_TBOOLEAN,
-LUA_TSTRING,
-LUA_TTABLE,
-LUA_TFUNCTION,
-LUA_TUSERDATA,
-LUA_TTHREAD,
-and
-LUA_TLIGHTUSERDATA.
-
-
-
-
-
-lua_typenameconst char *lua_typename (lua_State *L, int tp);
-
-tp,
-which must be one the values returned by lua_type.
-
-
-
-
-
-
-lua_Writertypedef int (*lua_Writer) (lua_State *L,
- const void* p,
- size_t sz,
- void* ud);
-
-lua_dump.
-Every time it produces another piece of chunk,
-lua_dump calls the writer,
-passing along the buffer to be written (p),
-its size (sz),
-and the data parameter supplied to lua_dump.
-
-
-lua_dump from
-calling the writer again.
-
-
-
-
-
-lua_xmovevoid lua_xmove (lua_State *from, lua_State *to, int n);
-
-n values from the stack from,
-and pushes them onto the stack to.
-
-
-
-
-
-lua_yieldint lua_yield (lua_State *L, int nresults);
-
-
- return lua_yield (L, nresults);
-
lua_yield in that way,
-the running coroutine suspends its execution,
-and the call to lua_resume that started this coroutine returns.
-The parameter nresults is the number of values from the stack
-that are passed as results to lua_resume.
-
-
-
-
-
-
-
-3.8 - The Debug Interface
-
-
-lua_Debugtypedef struct lua_Debug {
- int event;
- const char *name; /* (n) */
- const char *namewhat; /* (n) */
- const char *what; /* (S) */
- const char *source; /* (S) */
- int currentline; /* (l) */
- int nups; /* (u) number of upvalues */
- int linedefined; /* (S) */
- int lastlinedefined; /* (S) */
- char short_src[LUA_IDSIZE]; /* (S) */
- /* private part */
- other fields
-} lua_Debug;
-
-lua_getstack fills only the private part
-of this structure, for later use.
-To fill the other fields of lua_Debug with useful information,
-call lua_getinfo.
-
-
-lua_Debug have the following meaning:
-
-
-
-
-
-
-
-
-source:
-If the function was defined in a string,
-then source is that string.
-If the function was defined in a file,
-then source starts with a '@' followed by the file name.
-short_src:
-a "printable" version of source, to be used in error messages.
-linedefined:
-the line number where the definition of the function starts.
-lastlinedefined:
-the line number where the definition of the function ends.
-what:
-the string "Lua" if the function is a Lua function,
-"C" if it is a C function,
-"main" if it is the main part of a chunk,
-and "tail" if it was a function that did a tail call.
-In the latter case,
-Lua has no other information about the function.
-currentline:
-the current line where the given function is executing.
-When no line information is available,
-currentline is set to -1.
-name:
-a reasonable name for the given function.
-Because functions in Lua are first-class values,
-they do not have a fixed name:
-some functions may be the value of multiple global variables,
-while others may be stored only in a table field.
-The lua_getinfo function checks how the function was
-called to find a suitable name.
-If it cannot find a name,
-then name is set to NULL.
-namewhat:
-explains the name field.
-The value of namewhat can be
-"global", "local", "method",
-"field", "upvalue", or "" (the empty string),
-according to how the function was called.
-(Lua uses the empty string when no other option seems to apply.)
-nups:
-the number of upvalues of the function.
-lua_gethooklua_Hook lua_gethook (lua_State *L);
-
-lua_gethookcountint lua_gethookcount (lua_State *L);
-
-lua_gethookmaskint lua_gethookmask (lua_State *L);
-
-lua_getinfoint lua_getinfo (lua_State *L, const char *what, lua_Debug *ar);
-
-ar must be a valid activation record that was
-filled by a previous call to lua_getstack or
-given as argument to a hook (see lua_Hook).
-
-
-what string with the character '>'.
-(In that case,
-lua_getinfo pops the function in the top of the stack.)
-For instance, to know in which line a function f was defined,
-you can write the following code:
-
-
- lua_Debug ar;
- lua_getfield(L, LUA_GLOBALSINDEX, "f"); /* get global 'f' */
- lua_getinfo(L, ">S", &ar);
- printf("%d\n", ar.linedefined);
-
-
-what
-selects some fields of the structure ar to be filled or
-a value to be pushed on the stack:
-
-
-
-
-
-n': fills in the field name and namewhat;
-S':
-fills in the fields source, short_src,
-linedefined, lastlinedefined, and what;
-l': fills in the field currentline;
-u': fills in the field nups;
-f':
-pushes onto the stack the function that is
-running at the given level;
-L':
-pushes onto the stack a table whose indices are the
-numbers of the lines that are valid on the function.
-(A valid line is a line with some associated code,
-that is, a line where you can put a break point.
-Non-valid lines include empty lines and comments.)
-what).
-
-
-
-
-
-lua_getlocalconst char *lua_getlocal (lua_State *L, lua_Debug *ar, int n);
-
-ar must be a valid activation record that was
-filled by a previous call to lua_getstack or
-given as argument to a hook (see lua_Hook).
-The index n selects which local variable to inspect
-(1 is the first parameter or active local variable, and so on,
-until the last active local variable).
-lua_getlocal pushes the variable's value onto the stack
-and returns its name.
-
-
-(' (open parentheses)
-represent internal variables
-(loop control variables, temporaries, and C function locals).
-
-
-NULL (and pushes nothing)
-when the index is greater than
-the number of active local variables.
-
-
-
-
-
-lua_getstackint lua_getstack (lua_State *L, int level, lua_Debug *ar);
-
-lua_Debug structure with
-an identification of the activation record
-of the function executing at a given level.
-Level 0 is the current running function,
-whereas level n+1 is the function that has called level n.
-When there are no errors, lua_getstack returns 1;
-when called with a level greater than the stack depth,
-it returns 0.
-
-
-
-
-
-lua_getupvalueconst char *lua_getupvalue (lua_State *L, int funcindex, int n);
-
-lua_getupvalue gets the index n of an upvalue,
-pushes the upvalue's value onto the stack,
-and returns its name.
-funcindex points to the closure in the stack.
-(Upvalues have no particular order,
-as they are active through the whole function.
-So, they are numbered in an arbitrary order.)
-
-
-NULL (and pushes nothing)
-when the index is greater than the number of upvalues.
-For C functions, this function uses the empty string ""
-as a name for all upvalues.
-
-
-
-
-
-
-lua_Hooktypedef void (*lua_Hook) (lua_State *L, lua_Debug *ar);
-
-ar argument has its field
-event set to the specific event that triggered the hook.
-Lua identifies these events with the following constants:
-LUA_HOOKCALL, LUA_HOOKRET,
-LUA_HOOKTAILRET, LUA_HOOKLINE,
-and LUA_HOOKCOUNT.
-Moreover, for line events, the field currentline is also set.
-To get the value of any other field in ar,
-the hook must call lua_getinfo.
-For return events, event may be LUA_HOOKRET,
-the normal value, or LUA_HOOKTAILRET.
-In the latter case, Lua is simulating a return from
-a function that did a tail call;
-in this case, it is useless to call lua_getinfo.
-
-
-lua_sethookint lua_sethook (lua_State *L, lua_Hook f, int mask, int count);
-
-f is the hook function.
-mask specifies on which events the hook will be called:
-it is formed by a bitwise or of the constants
-LUA_MASKCALL,
-LUA_MASKRET,
-LUA_MASKLINE,
-and LUA_MASKCOUNT.
-The count argument is only meaningful when the mask
-includes LUA_MASKCOUNT.
-For each event, the hook is called as explained below:
-
-
-
-
-
-count instructions.
-(This event only happens while Lua is executing a Lua function.)
-mask to zero.
-
-
-
-
-
-lua_setlocalconst char *lua_setlocal (lua_State *L, lua_Debug *ar, int n);
-
-ar and n are as in lua_getlocal
-(see lua_getlocal).
-lua_setlocal assigns the value at the top of the stack
-to the variable and returns its name.
-It also pops the value from the stack.
-
-
-NULL (and pops nothing)
-when the index is greater than
-the number of active local variables.
-
-
-
-
-
-lua_setupvalueconst char *lua_setupvalue (lua_State *L, int funcindex, int n);
-
-funcindex and n are as in the lua_getupvalue
-(see lua_getupvalue).
-
-
-NULL (and pops nothing)
-when the index is greater than the number of upvalues.
-
-
-
-
-
-
-
-4 - The Auxiliary Library
-
-lauxlib.h and
-have a prefix luaL_.
-
-
-luaL_check* or luaL_opt*.
-All of these functions throw an error if the check is not satisfied.
-Because the error message is formatted for arguments
-(e.g., "bad argument #1"),
-you should not use these functions for other stack values.
-
-
-
-4.1 - Functions and Types
-
-luaL_addcharvoid luaL_addchar (luaL_Buffer *B, char c);
-
-c to the buffer B
-(see luaL_Buffer).
-
-
-
-
-
-luaL_addlstringvoid luaL_addlstring (luaL_Buffer *B, const char *s, size_t l);
-
-s with length l to
-the buffer B
-(see luaL_Buffer).
-The string may contain embedded zeros.
-
-
-
-
-
-luaL_addsizevoid luaL_addsize (luaL_Buffer *B, size_t n);
-
-B (see luaL_Buffer)
-a string of length n previously copied to the
-buffer area (see luaL_prepbuffer).
-
-
-
-
-
-luaL_addstringvoid luaL_addstring (luaL_Buffer *B, const char *s);
-
-s
-to the buffer B
-(see luaL_Buffer).
-The string may not contain embedded zeros.
-
-
-
-
-
-luaL_addvaluevoid luaL_addvalue (luaL_Buffer *B);
-
-B
-(see luaL_Buffer).
-Pops the value.
-
-
-luaL_argcheckvoid luaL_argcheck (lua_State *L,
- int cond,
- int narg,
- const char *extramsg);
-
-cond is true.
-If not, raises an error with the following message,
-where func is retrieved from the call stack:
-
-
- bad argument #<narg> to <func> (<extramsg>)
-
-
-
-
-
-luaL_argerrorint luaL_argerror (lua_State *L, int narg, const char *extramsg);
-
-func is retrieved from the call stack:
-
-
- bad argument #<narg> to <func> (<extramsg>)
-
-
-return luaL_argerror(args).
-
-
-
-
-
-
-luaL_Buffertypedef struct luaL_Buffer luaL_Buffer;
-
-
-
-
-
-b of type luaL_Buffer.luaL_buffinit(L, &b).luaL_add* functions.
-luaL_pushresult(&b).
-This call leaves the final string on the top of the stack.
-luaL_addvalue.)
-After calling luaL_pushresult the stack is back to its
-level when the buffer was initialized,
-plus the final string on its top.
-
-
-
-
-
-luaL_buffinitvoid luaL_buffinit (lua_State *L, luaL_Buffer *B);
-
-B.
-This function does not allocate any space;
-the buffer must be declared as a variable
-(see luaL_Buffer).
-
-
-
-
-
-luaL_callmetaint luaL_callmeta (lua_State *L, int obj, const char *e);
-
-obj has a metatable and this
-metatable has a field e,
-this function calls this field and passes the object as its only argument.
-In this case this function returns 1 and pushes onto the
-stack the value returned by the call.
-If there is no metatable or no metamethod,
-this function returns 0 (without pushing any value on the stack).
-
-
-
-
-
-luaL_checkanyvoid luaL_checkany (lua_State *L, int narg);
-
-narg.
-
-
-
-
-
-luaL_checkintint luaL_checkint (lua_State *L, int narg);
-
-narg is a number
-and returns this number cast to an int.
-
-
-
-
-
-luaL_checkintegerlua_Integer luaL_checkinteger (lua_State *L, int narg);
-
-narg is a number
-and returns this number cast to a lua_Integer.
-
-
-
-
-
-luaL_checklonglong luaL_checklong (lua_State *L, int narg);
-
-narg is a number
-and returns this number cast to a long.
-
-
-
-
-
-luaL_checklstringconst char *luaL_checklstring (lua_State *L, int narg, size_t *l);
-
-narg is a string
-and returns this string;
-if l is not NULL fills *l
-with the string's length.
-
-
-lua_tolstring to get its result,
-so all conversions and caveats of that function apply here.
-
-
-
-
-
-luaL_checknumberlua_Number luaL_checknumber (lua_State *L, int narg);
-
-narg is a number
-and returns this number.
-
-
-
-
-
-luaL_checkoptionint luaL_checkoption (lua_State *L,
- int narg,
- const char *def,
- const char *const lst[]);
-
-narg is a string and
-searches for this string in the array lst
-(which must be NULL-terminated).
-Returns the index in the array where the string was found.
-Raises an error if the argument is not a string or
-if the string cannot be found.
-
-
-def is not NULL,
-the function uses def as a default value when
-there is no argument narg or if this argument is nil.
-
-
-luaL_checkstackvoid luaL_checkstack (lua_State *L, int sz, const char *msg);
-
-top + sz elements,
-raising an error if the stack cannot grow to that size.
-msg is an additional text to go into the error message.
-
-
-
-
-
-luaL_checkstringconst char *luaL_checkstring (lua_State *L, int narg);
-
-narg is a string
-and returns this string.
-
-
-lua_tolstring to get its result,
-so all conversions and caveats of that function apply here.
-
-
-
-
-
-luaL_checktypevoid luaL_checktype (lua_State *L, int narg, int t);
-
-narg has type t.
-See lua_type for the encoding of types for t.
-
-
-
-
-
-luaL_checkudatavoid *luaL_checkudata (lua_State *L, int narg, const char *tname);
-
-narg is a userdata
-of the type tname (see luaL_newmetatable).
-
-
-
-
-
-luaL_dofileint luaL_dofile (lua_State *L, const char *filename);
-
-
- (luaL_loadfile(L, filename) || lua_pcall(L, 0, LUA_MULTRET, 0))
-
luaL_dostringint luaL_dostring (lua_State *L, const char *str);
-
-
- (luaL_loadstring(L, str) || lua_pcall(L, 0, LUA_MULTRET, 0))
-
luaL_errorint luaL_error (lua_State *L, const char *fmt, ...);
-
-fmt
-plus any extra arguments,
-following the same rules of lua_pushfstring.
-It also adds at the beginning of the message the file name and
-the line number where the error occurred,
-if this information is available.
-
-
-return luaL_error(args).
-
-
-
-
-
-luaL_getmetafieldint luaL_getmetafield (lua_State *L, int obj, const char *e);
-
-e from the metatable
-of the object at index obj.
-If the object does not have a metatable,
-or if the metatable does not have this field,
-returns 0 and pushes nothing.
-
-
-
-
-
-luaL_getmetatablevoid luaL_getmetatable (lua_State *L, const char *tname);
-
-tname
-in the registry (see luaL_newmetatable).
-
-
-
-
-
-luaL_gsubconst char *luaL_gsub (lua_State *L,
- const char *s,
- const char *p,
- const char *r);
-
-s by replacing
-any occurrence of the string p
-with the string r.
-Pushes the resulting string on the stack and returns it.
-
-
-
-
-
-luaL_loadbufferint luaL_loadbuffer (lua_State *L,
- const char *buff,
- size_t sz,
- const char *name);
-
-lua_load to load the chunk in the
-buffer pointed to by buff with size sz.
-
-
-lua_load.
-name is the chunk name,
-used for debug information and error messages.
-
-
-
-
-
-luaL_loadfileint luaL_loadfile (lua_State *L, const char *filename);
-
-lua_load to load the chunk in the file
-named filename.
-If filename is NULL,
-then it loads from the standard input.
-The first line in the file is ignored if it starts with a #.
-
-
-lua_load,
-but it has an extra error code LUA_ERRFILE
-if it cannot open/read the file.
-
-
-lua_load, this function only loads the chunk;
-it does not run it.
-
-
-
-
-
-luaL_loadstringint luaL_loadstring (lua_State *L, const char *s);
-
-lua_load to load the chunk in
-the zero-terminated string s.
-
-
-lua_load.
-
-
-lua_load, this function only loads the chunk;
-it does not run it.
-
-
-
-
-
-luaL_newmetatableint luaL_newmetatable (lua_State *L, const char *tname);
-
-tname,
-returns 0.
-Otherwise,
-creates a new table to be used as a metatable for userdata,
-adds it to the registry with key tname,
-and returns 1.
-
-
-tname in the registry.
-
-
-
-
-
-luaL_newstatelua_State *luaL_newstate (void);
-
-lua_newstate with an
-allocator based on the standard C realloc function
-and then sets a panic function (see lua_atpanic) that prints
-an error message to the standard error output in case of fatal
-errors.
-
-
-NULL if there is a memory allocation error.
-
-
-
-
-
-luaL_openlibsvoid luaL_openlibs (lua_State *L);
-
-luaL_optintint luaL_optint (lua_State *L, int narg, int d);
-
-narg is a number,
-returns this number cast to an int.
-If this argument is absent or is nil,
-returns d.
-Otherwise, raises an error.
-
-
-
-
-
-luaL_optintegerlua_Integer luaL_optinteger (lua_State *L,
- int narg,
- lua_Integer d);
-
-narg is a number,
-returns this number cast to a lua_Integer.
-If this argument is absent or is nil,
-returns d.
-Otherwise, raises an error.
-
-
-
-
-
-luaL_optlonglong luaL_optlong (lua_State *L, int narg, long d);
-
-narg is a number,
-returns this number cast to a long.
-If this argument is absent or is nil,
-returns d.
-Otherwise, raises an error.
-
-
-
-
-
-luaL_optlstringconst char *luaL_optlstring (lua_State *L,
- int narg,
- const char *d,
- size_t *l);
-
-narg is a string,
-returns this string.
-If this argument is absent or is nil,
-returns d.
-Otherwise, raises an error.
-
-
-l is not NULL,
-fills the position *l with the results's length.
-
-
-
-
-
-luaL_optnumberlua_Number luaL_optnumber (lua_State *L, int narg, lua_Number d);
-
-narg is a number,
-returns this number.
-If this argument is absent or is nil,
-returns d.
-Otherwise, raises an error.
-
-
-
-
-
-luaL_optstringconst char *luaL_optstring (lua_State *L,
- int narg,
- const char *d);
-
-narg is a string,
-returns this string.
-If this argument is absent or is nil,
-returns d.
-Otherwise, raises an error.
-
-
-
-
-
-luaL_prepbufferchar *luaL_prepbuffer (luaL_Buffer *B);
-
-LUAL_BUFFERSIZE
-where you can copy a string to be added to buffer B
-(see luaL_Buffer).
-After copying the string into this space you must call
-luaL_addsize with the size of the string to actually add
-it to the buffer.
-
-
-
-
-
-luaL_pushresultvoid luaL_pushresult (luaL_Buffer *B);
-
-B leaving the final string on
-the top of the stack.
-
-
-
-
-
-luaL_refint luaL_ref (lua_State *L, int t);
-
-t,
-for the object at the top of the stack (and pops the object).
-
-
-t,
-luaL_ref ensures the uniqueness of the key it returns.
-You can retrieve an object referred by reference r
-by calling lua_rawgeti(L, t, r).
-Function luaL_unref frees a reference and its associated object.
-
-
-luaL_ref returns the constant LUA_REFNIL.
-The constant LUA_NOREF is guaranteed to be different
-from any reference returned by luaL_ref.
-
-
-
-
-
-
-luaL_Regtypedef struct luaL_Reg {
- const char *name;
- lua_CFunction func;
-} luaL_Reg;
-
-luaL_register.
-name is the function name and func is a pointer to
-the function.
-Any array of luaL_Reg must end with an sentinel entry
-in which both name and func are NULL.
-
-
-
-
-
-luaL_registervoid luaL_register (lua_State *L,
- const char *libname,
- const luaL_Reg *l);
-
-libname equal to NULL,
-it simply registers all functions in the list l
-(see luaL_Reg) into the table on the top of the stack.
-
-
-libname,
-luaL_register creates a new table t,
-sets it as the value of the global variable libname,
-sets it as the value of package.loaded[libname],
-and registers on it all functions in the list l.
-If there is a table in package.loaded[libname] or in
-variable libname,
-reuses this table instead of creating a new one.
-
-
-luaL_typenameconst char *luaL_typename (lua_State *L, int index);
-
-luaL_typerrorint luaL_typerror (lua_State *L, int narg, const char *tname);
-
-
- location: bad argument narg to 'func' (tname expected, got rt)
-
location is produced by luaL_where,
-func is the name of the current function,
-and rt is the type name of the actual argument.
-
-
-
-
-
-luaL_unrefvoid luaL_unref (lua_State *L, int t, int ref);
-
-ref from the table at index t
-(see luaL_ref).
-The entry is removed from the table,
-so that the referred object can be collected.
-The reference ref is also freed to be used again.
-
-
-ref is LUA_NOREF or LUA_REFNIL,
-luaL_unref does nothing.
-
-
-
-
-
-luaL_wherevoid luaL_where (lua_State *L, int lvl);
-
-lvl in the call stack.
-Typically this string has the following format:
-
-
- chunkname:currentline:
-
5 - Standard Libraries
-
-type and getmetatable);
-others provide access to "outside" services (e.g., I/O);
-and others could be implemented in Lua itself,
-but are quite useful or have critical performance requirements that
-deserve an implementation in C (e.g., table.sort).
-
-
-
-
-
luaL_openlibs function,
-which opens all standard libraries.
-Alternatively,
-it can open them individually by calling
-luaopen_base (for the basic library),
-luaopen_package (for the package library),
-luaopen_string (for the string library),
-luaopen_table (for the table library),
-luaopen_math (for the mathematical library),
-luaopen_io (for the I/O library),
-luaopen_os (for the Operating System library),
-and luaopen_debug (for the debug library).
-These functions are declared in lualib.h
-and should not be called directly:
-you must call them like any other Lua C function,
-e.g., by using lua_call.
-
-
-
-5.1 - Basic Functions
-
-
-Issues an error when
-the value of its argument assert (v [, message])v is false (i.e., nil or false);
-otherwise, returns all its arguments.
-message is an error message;
-when absent, it defaults to "assertion failed!"
-
-
-
-
-
-
-
-collectgarbage (opt [, arg])opt:
-
-
-
-
-
-
-
-arg
-(larger values mean more steps) in a non-specified way.
-If you want to control the step size
-you must experimentally tune the value of arg.
-Returns true if the step finished a collection cycle.
-arg/100 as the new value for the pause of
-the collector (see §2.10).
-arg/100 as the new value for the step multiplier of
-the collector (see §2.10).
-
-Opens the named file and executes its contents as a Lua chunk.
-When called without arguments,
-dofile (filename)dofile executes the contents of the standard input (stdin).
-Returns all values returned by the chunk.
-In case of errors, dofile propagates the error
-to its caller (that is, dofile does not run in protected mode).
-
-
-
-
-
-Terminates the last protected function called
-and returns error (message [, level])message as the error message.
-Function error never returns.
-
-
-error adds some information about the error position
-at the beginning of the message.
-The level argument specifies how to get the error position.
-With level 1 (the default), the error position is where the
-error function was called.
-Level 2 points the error to where the function
-that called error was called; and so on.
-Passing a level 0 avoids the addition of error position information
-to the message.
-
-
-
-
-
-A global variable (not a function) that
-holds the global environment (that is, _G_G._G = _G).
-Lua itself does not use this variable;
-changing its value does not affect any environment,
-nor vice-versa.
-(Use setfenv to change environments.)
-
-
-
-
-
-Returns the current environment in use by the function.
-getfenv ([f])f can be a Lua function or a number
-that specifies the function at that stack level:
-Level 1 is the function calling getfenv.
-If the given function is not a Lua function,
-or if f is 0,
-getfenv returns the global environment.
-The default for f is 1.
-
-
-
-
-
-
-
-getmetatable (object)object does not have a metatable, returns nil.
-Otherwise,
-if the object's metatable has a "__metatable" field,
-returns the associated value.
-Otherwise, returns the metatable of the given object.
-
-
-
-
-
-
-
-ipairs (t)t, and 0,
-so that the construction
-
-
- for i,v in ipairs(t) do body end
-
1,t[1]), (2,t[2]), ···,
-up to the first integer key absent from the table.
-
-
-
-
-
-
-
-load (func [, chunkname])func to get its pieces.
-Each call to func must return a string that concatenates
-with previous results.
-A return of nil (or no value) signals the end of the chunk.
-
-
-chunkname is used as the chunk name for error messages
-and debug information.
-When absent,
-it defaults to "=(load)".
-
-
-
-
-
-
-
-loadfile ([filename])load,
-but gets the chunk from file filename
-or from the standard input,
-if no file name is given.
-
-
-
-
-
-
-
-loadstring (string [, chunkname])load,
-but gets the chunk from the given string.
-
-
-
- assert(loadstring(s))()
-
-
-chunkname defaults to the given string.
-
-
-
-
-
-
-
-next (table [, index])next returns the next index of the table
-and its associated value.
-When called with nil as its second argument,
-next returns an initial index
-and its associated value.
-When called with the last index,
-or with nil in an empty table,
-next returns nil.
-If the second argument is absent, then it is interpreted as nil.
-In particular,
-you can use next(t) to check whether a table is empty.
-
-
-ipairs function.)
-
-
-next is undefined if,
-during the traversal,
-you assign any value to a non-existent field in the table.
-You may however modify existing fields.
-In particular, you may clear existing fields.
-
-
-
-
-
-
-
-pairs (t)next function, the table t, and nil,
-so that the construction
-
-
- for k,v in pairs(t) do body end
-
t.
-
-
-next for the caveats of modifying
-the table during its traversal.
-
-
-
-
-
-
-
-pcall (f, arg1, ···)f with
-the given arguments in protected mode.
-This means that any error inside f is not propagated;
-instead, pcall catches the error
-and returns a status code.
-Its first result is the status code (a boolean),
-which is true if the call succeeds without errors.
-In such case, pcall also returns all results from the call,
-after this first result.
-In case of any error, pcall returns false plus the error message.
-
-
-
-
-
-Receives any number of arguments,
-and prints their values to print (···)stdout,
-using the tostring function to convert them to strings.
-print is not intended for formatted output,
-but only as a quick way to show a value,
-typically for debugging.
-For formatted output, use string.format.
-
-
-
-
-
-Checks whether rawequal (v1, v2)v1 is equal to v2,
-without invoking any metamethod.
-Returns a boolean.
-
-
-
-
-
-Gets the real value of rawget (table, index)table[index],
-without invoking any metamethod.
-table must be a table;
-index may be any value.
-
-
-
-
-
-Sets the real value of rawset (table, index, value)table[index] to value,
-without invoking any metamethod.
-table must be a table,
-index any value different from nil,
-and value any Lua value.
-
-
-table.
-
-
-
-
-
-
-
-select (index, ···)index is a number,
-returns all arguments after argument number index.
-Otherwise, index must be the string "#",
-and select returns the total number of extra arguments it received.
-
-
-
-
-
-
-
-setfenv (f, table)f can be a Lua function or a number
-that specifies the function at that stack level:
-Level 1 is the function calling setfenv.
-setfenv returns the given function.
-
-
-f is 0 setfenv changes
-the environment of the running thread.
-In this case, setfenv returns no values.
-
-
-
-
-
-
-
-setmetatable (table, metatable)metatable is nil,
-removes the metatable of the given table.
-If the original metatable has a "__metatable" field,
-raises an error.
-
-
-table.
-
-
-
-
-
-Tries to convert its argument to a number.
-If the argument is already a number or a string convertible
-to a number, then tonumber (e [, base])tonumber returns this number;
-otherwise, it returns nil.
-
-
-A' (in either upper or lower case)
-represents 10, 'B' represents 11, and so forth,
-with 'Z' representing 35.
-In base 10 (the default), the number may have a decimal part,
-as well as an optional exponent part (see §2.1).
-In other bases, only unsigned integers are accepted.
-
-
-
-
-
-Receives an argument of any type and
-converts it to a string in a reasonable format.
-For complete control of how numbers are converted,
-use tostring (e)string.format.
-
-
-e has a "__tostring" field,
-then tostring calls the corresponding value
-with e as argument,
-and uses the result of the call as its result.
-
-
-
-
-
-Returns the type of its only argument, coded as a string.
-The possible results of this function are
-"type (v)nil" (a string, not the value nil),
-"number",
-"string",
-"boolean",
-"table",
-"function",
-"thread",
-and "userdata".
-
-
-
-
-
-Returns the elements from the given table.
-This function is equivalent to
-
-unpack (list [, i [, j]])
- return list[i], list[i+1], ···, list[j]
-
i is 1 and j is the length of the list,
-as defined by the length operator (see §2.5.5).
-
-
-
-
-
-A global variable (not a function) that
-holds a string containing the current interpreter version.
-The current contents of this variable is "_VERSIONLua 5.1".
-
-
-
-
-
-
-
-xpcall (f, err)pcall,
-except that you can set a new error handler.
-
-
-xpcall calls function f in protected mode,
-using err as the error handler.
-Any error inside f is not propagated;
-instead, xpcall catches the error,
-calls the err function with the original error object,
-and returns a status code.
-Its first result is the status code (a boolean),
-which is true if the call succeeds without errors.
-In this case, xpcall also returns all results from the call,
-after this first result.
-In case of any error,
-xpcall returns false plus the result from err.
-
-
-
-
-
-
-
-5.2 - Coroutine Manipulation
-
-coroutine.
-See §2.11 for a general description of coroutines.
-
-
-
-
-
-coroutine.create (f)f.
-f must be a Lua function.
-Returns this new coroutine,
-an object with type "thread".
-
-
-
-
-
-
-
-coroutine.resume (co [, val1, ···])co.
-The first time you resume a coroutine,
-it starts running its body.
-The values val1, ··· are passed
-as the arguments to the body function.
-If the coroutine has yielded,
-resume restarts it;
-the values val1, ··· are passed
-as the results from the yield.
-
-
-resume returns true plus any values passed to yield
-(if the coroutine yields) or any values returned by the body function
-(if the coroutine terminates).
-If there is any error,
-resume returns false plus the error message.
-
-
-
-
-
-
-
-coroutine.running ()
-
-
-coroutine.status (co)co, as a string:
-"running",
-if the coroutine is running (that is, it called status);
-"suspended", if the coroutine is suspended in a call to yield,
-or if it has not started running yet;
-"normal" if the coroutine is active but not running
-(that is, it has resumed another coroutine);
-and "dead" if the coroutine has finished its body function,
-or if it has stopped with an error.
-
-
-
-
-
-
-
-coroutine.wrap (f)f.
-f must be a Lua function.
-Returns a function that resumes the coroutine each time it is called.
-Any arguments passed to the function behave as the
-extra arguments to resume.
-Returns the same values returned by resume,
-except the first boolean.
-In case of error, propagates the error.
-
-
-
-
-
-
-
-coroutine.yield (···)yield are passed as extra results to resume.
-
-
-
-
-
-
-
-5.3 - Modules
-
-require and module.
-Everything else is exported in a table package.
-
-
-
-
-
-module (name [, ···])package.loaded[name],
-this table is the module.
-Otherwise, if there is a global table t with the given name,
-this table is the module.
-Otherwise creates a new table t and
-sets it as the value of the global name and
-the value of package.loaded[name].
-This function also initializes t._NAME with the given name,
-t._M with the module (t itself),
-and t._PACKAGE with the package name
-(the full module name minus last component; see below).
-Finally, module sets t as the new environment
-of the current function and the new value of package.loaded[name],
-so that require returns t.
-
-
-name is a compound name
-(that is, one with components separated by dots),
-module creates (or reuses, if they already exist)
-tables for each component.
-For instance, if name is a.b.c,
-then module stores the module table in field c of
-field b of global a.
-
-
-
-
-
-require (modname)package.loaded table
-to determine whether modname is already loaded.
-If it is, then require returns the value stored
-at package.loaded[modname].
-Otherwise, it tries to find a loader for the module.
-
-
-require is guided by the package.loaders array.
-By changing this array,
-we can change how require looks for a module.
-The following explanation is based on the default configuration
-for package.loaders.
-
-
-require queries package.preload[modname].
-If it has a value,
-this value (which should be a function) is the loader.
-Otherwise require searches for a Lua loader using the
-path stored in package.path.
-If that also fails, it searches for a C loader using the
-path stored in package.cpath.
-If that also fails,
-it tries an all-in-one loader (see package.loaders).
-
-
-require calls the loader with a single argument, modname.
-If the loader returns any value,
-require assigns the returned value to package.loaded[modname].
-If the loader returns no value and
-has not assigned any value to package.loaded[modname],
-then require assigns true to this entry.
-In any case, require returns the
-final value of package.loaded[modname].
-
-
-require signals an error.
-
-
-
-
-
-
-
-package.cpathrequire to search for a C loader.
-
-
-package.cpath in the same way
-it initializes the Lua path package.path,
-using the environment variable LUA_CPATH
-or a default path defined in luaconf.h.
-
-
-
-
-
-
-
-package.loadedrequire to control which
-modules are already loaded.
-When you require a module modname and
-package.loaded[modname] is not false,
-require simply returns the value stored there.
-
-
-
-
-
-
-
-package.loadersrequire to control how to load modules.
-
-
-require calls each of these searchers in ascending order,
-with the module name (the argument given to require) as its
-sole parameter.
-The function may return another function (the module loader)
-or a string explaining why it did not find that module
-(or nil if it has nothing to say).
-Lua initializes this table with four functions.
-
-
-package.preload table.
-
-
-package.path.
-A path is a sequence of templates separated by semicolons.
-For each template,
-the searcher will change each interrogation
-mark in the template by filename,
-which is the module name with each dot replaced by a
-"directory separator" (such as "/" in Unix);
-then it will try to open the resulting file name.
-So, for instance, if the Lua path is the string
-
-
- "./?.lua;./?.lc;/usr/local/?/init.lua"
-
foo
-will try to open the files
-./foo.lua, ./foo.lc, and
-/usr/local/foo/init.lua, in that order.
-
-
-package.cpath.
-For instance,
-if the C path is the string
-
-
- "./?.so;./?.dll;/usr/local/?/init.so"
-
foo
-will try to open the files ./foo.so, ./foo.dll,
-and /usr/local/foo/init.so, in that order.
-Once it finds a C library,
-this searcher first uses a dynamic link facility to link the
-application with the library.
-Then it tries to find a C function inside the library to
-be used as the loader.
-The name of this C function is the string "luaopen_"
-concatenated with a copy of the module name where each dot
-is replaced by an underscore.
-Moreover, if the module name has a hyphen,
-its prefix up to (and including) the first hyphen is removed.
-For instance, if the module name is a.v1-b.c,
-the function name will be luaopen_b_c.
-
-
-a.b.c,
-it will search for a C library for a.
-If found, it looks into it for an open function for
-the submodule;
-in our example, that would be luaopen_a_b_c.
-With this facility, a package can pack several C submodules
-into one single library,
-with each submodule keeping its original open function.
-
-
-
-
-
-
-
-package.loadlib (libname, funcname)libname.
-Inside this library, looks for a function funcname
-and returns this function as a C function.
-(So, funcname must follow the protocol (see lua_CFunction)).
-
-
-require,
-it does not perform any path searching and
-does not automatically adds extensions.
-libname must be the complete file name of the C library,
-including if necessary a path and extension.
-funcname must be the exact name exported by the C library
-(which may depend on the C compiler and linker used).
-
-
-dlfcn standard).
-
-
-
-
-
-
-
-package.pathrequire to search for a Lua loader.
-
-
-LUA_PATH or
-with a default path defined in luaconf.h,
-if the environment variable is not defined.
-Any ";;" in the value of the environment variable
-is replaced by the default path.
-
-
-
-
-
-
-
-package.preloadrequire).
-
-
-
-
-
-
-
-package.seeall (module)module with
-its __index field referring to the global environment,
-so that this module inherits values
-from the global environment.
-To be used as an option to function module.
-
-
-
-
-
-
-
-5.4 - String Manipulation
-
-string.
-It also sets a metatable for strings
-where the __index field points to the string table.
-Therefore, you can use the string functions in object-oriented style.
-For instance, string.byte(s, i)
-can be written as s:byte(i).
-
-
-
-Returns the internal numerical codes of the characters string.byte (s [, i [, j]])s[i],
-s[i+1], ···, s[j].
-The default value for i is 1;
-the default value for j is i.
-
-
-
-Receives zero or more integers.
-Returns a string with length equal to the number of arguments,
-in which each character has the internal numerical code equal
-to its corresponding argument.
-
-
-string.char (···)
-
-
-string.dump (function)loadstring on this string returns
-a copy of the function.
-function must be a Lua function without upvalues.
-
-
-
-
-
-Looks for the first match of
-string.find (s, pattern [, init [, plain]])pattern in the string s.
-If it finds a match, then find returns the indices of s
-where this occurrence starts and ends;
-otherwise, it returns nil.
-A third, optional numerical argument init specifies
-where to start the search;
-its default value is 1 and may be negative.
-A value of true as a fourth, optional argument plain
-turns off the pattern matching facilities,
-so the function does a plain "find substring" operation,
-with no characters in pattern being considered "magic".
-Note that if plain is given, then init must be given as well.
-
-
-
-Returns a formatted version of its variable number of arguments
-following the description given in its first argument (which must be a string).
-The format string follows the same rules as the string.format (formatstring, ···)printf family of
-standard C functions.
-The only differences are that the options/modifiers
-*, l, L, n, p,
-and h are not supported
-and that there is an extra option, q.
-The q option formats a string in a form suitable to be safely read
-back by the Lua interpreter:
-the string is written between double quotes,
-and all double quotes, newlines, embedded zeros,
-and backslashes in the string
-are correctly escaped when written.
-For instance, the call
-
-
- string.format('%q', 'a string with "quotes" and \n new line')
-
- "a string with \"quotes\" and \
- new line"
-
-
-c, d, E, e, f,
-g, G, i, o, u, X, and x all
-expect a number as argument,
-whereas q and s expect a string.
-
-
-q option.
-
-
-
-
-
-Returns an iterator function that,
-each time it is called,
-returns the next captures from string.gmatch (s, pattern)pattern over string s.
-If pattern specifies no captures,
-then the whole match is produced in each call.
-
-
-
- s = "hello world from Lua"
- for w in string.gmatch(s, "%a+") do
- print(w)
- end
-
s,
-printing one per line.
-The next example collects all pairs key=value from the
-given string into a table:
-
-
- t = {}
- s = "from=world, to=Lua"
- for k, v in string.gmatch(s, "(%w+)=(%w+)") do
- t[k] = v
- end
-
-
-^' at the start of a pattern does not
-work as an anchor, as this would prevent the iteration.
-
-
-
-
-
-Returns a copy of string.gsub (s, pattern, repl [, n])s
-in which all (or the first n, if given)
-occurrences of the pattern have been
-replaced by a replacement string specified by repl,
-which may be a string, a table, or a function.
-gsub also returns, as its second value,
-the total number of matches that occurred.
-
-
-repl is a string, then its value is used for replacement.
-The character % works as an escape character:
-any sequence in repl of the form %n,
-with n between 1 and 9,
-stands for the value of the n-th captured substring (see below).
-The sequence %0 stands for the whole match.
-The sequence %% stands for a single %.
-
-
-repl is a table, then the table is queried for every match,
-using the first capture as the key;
-if the pattern specifies no captures,
-then the whole match is used as the key.
-
-
-repl is a function, then this function is called every time a
-match occurs, with all captured substrings passed as arguments,
-in order;
-if the pattern specifies no captures,
-then the whole match is passed as a sole argument.
-
-
-
- x = string.gsub("hello world", "(%w+)", "%1 %1")
- --> x="hello hello world world"
-
- x = string.gsub("hello world", "%w+", "%0 %0", 1)
- --> x="hello hello world"
-
- x = string.gsub("hello world from Lua", "(%w+)%s*(%w+)", "%2 %1")
- --> x="world hello Lua from"
-
- x = string.gsub("home = $HOME, user = $USER", "%$(%w+)", os.getenv)
- --> x="home = /home/roberto, user = roberto"
-
- x = string.gsub("4+5 = $return 4+5$", "%$(.-)%$", function (s)
- return loadstring(s)()
- end)
- --> x="4+5 = 9"
-
- local t = {name="lua", version="5.1"}
- x = string.gsub("$name-$version.tar.gz", "%$(%w+)", t)
- --> x="lua-5.1.tar.gz"
-
-
-
-
-
-Receives a string and returns its length.
-The empty string string.len (s)"" has length 0.
-Embedded zeros are counted,
-so "a\000bc\000" has length 5.
-
-
-
-
-
-Receives a string and returns a copy of this string with all
-uppercase letters changed to lowercase.
-All other characters are left unchanged.
-The definition of what an uppercase letter is depends on the current locale.
-
-
-
-
-string.lower (s)
-Looks for the first match of
-string.match (s, pattern [, init])pattern in the string s.
-If it finds one, then match returns
-the captures from the pattern;
-otherwise it returns nil.
-If pattern specifies no captures,
-then the whole match is returned.
-A third, optional numerical argument init specifies
-where to start the search;
-its default value is 1 and may be negative.
-
-
-
-
-
-Returns a string that is the concatenation of string.rep (s, n)n copies of
-the string s.
-
-
-
-
-
-Returns a string that is the string string.reverse (s)s reversed.
-
-
-
-
-
-Returns the substring of string.sub (s, i [, j])s that
-starts at i and continues until j;
-i and j may be negative.
-If j is absent, then it is assumed to be equal to -1
-(which is the same as the string length).
-In particular,
-the call string.sub(s,1,j) returns a prefix of s
-with length j,
-and string.sub(s, -i) returns a suffix of s
-with length i.
-
-
-
-
-
-Receives a string and returns a copy of this string with all
-lowercase letters changed to uppercase.
-All other characters are left unchanged.
-The definition of what a lowercase letter is depends on the current locale.
-
-
-
-string.upper (s)5.4.1 - Patterns
-
-
-Character Class:
-
-
^$()%.[]*+-?)
-represents the character x itself.
-.: (a dot) represents all characters.%a: represents all letters.%c: represents all control characters.%d: represents all digits.%l: represents all lowercase letters.%p: represents all punctuation characters.%s: represents all space characters.%u: represents all uppercase letters.%w: represents all alphanumeric characters.%x: represents all hexadecimal digits.%z: represents the character with representation 0.%x: (where x is any non-alphanumeric character)
-represents the character x.
-This is the standard way to escape the magic characters.
-Any punctuation character (even the non magic)
-can be preceded by a '%'
-when used to represent itself in a pattern.
-[set]:
-represents the class which is the union of all
-characters in set.
-A range of characters may be specified by
-separating the end characters of the range with a '-'.
-All classes %x described above may also be used as
-components in set.
-All other characters in set represent themselves.
-For example, [%w_] (or [_%w])
-represents all alphanumeric characters plus the underscore,
-[0-7] represents the octal digits,
-and [0-7%l%-] represents the octal digits plus
-the lowercase letters plus the '-' character.
-
-
-[%a-z] or [a-%%]
-have no meaning.
-[^set]:
-represents the complement of set,
-where set is interpreted as above.
-%a, %c, etc.),
-the corresponding uppercase letter represents the complement of the class.
-For instance, %S represents all non-space characters.
-
-
-[a-z] may not be equivalent to %l.
-
-
-
-
-
-Pattern Item:
-
-
-
-
-
-
-*',
-which matches 0 or more repetitions of characters in the class.
-These repetition items will always match the longest possible sequence;
-+',
-which matches 1 or more repetitions of characters in the class.
-These repetition items will always match the longest possible sequence;
--',
-which also matches 0 or more repetitions of characters in the class.
-Unlike '*',
-these repetition items will always match the shortest possible sequence;
-?',
-which matches 0 or 1 occurrence of a character in the class;
-%n, for n between 1 and 9;
-such item matches a substring equal to the n-th captured string
-(see below);
-%bxy, where x and y are two distinct characters;
-such item matches strings that start with x, end with y,
-and where the x and y are balanced.
-This means that, if one reads the string from left to right,
-counting +1 for an x and -1 for a y,
-the ending y is the first y where the count reaches 0.
-For instance, the item %b() matches expressions with
-balanced parentheses.
-Pattern:
^' at the beginning of a pattern anchors the match at the
-beginning of the subject string.
-A '$' at the end of a pattern anchors the match at the
-end of the subject string.
-At other positions,
-'^' and '$' have no special meaning and represent themselves.
-
-
-
-
-
-Captures:
"(a*(.)%w(%s*))",
-the part of the string matching "a*(.)%w(%s*)" is
-stored as the first capture (and therefore has number 1);
-the character matching "." is captured with number 2,
-and the part matching "%s*" has number 3.
-
-
-() captures
-the current string position (a number).
-For instance, if we apply the pattern "()aa()" on the
-string "flaaap", there will be two captures: 3 and 5.
-
-
-%z instead.
-
-
-
-
-
-
-
-
-
-
-
-5.5 - Table Manipulation
table.
-
-
-
-Given an array where all elements are strings or numbers,
-returns table.concat (table [, sep [, i [, j]]])table[i]..sep..table[i+1] ··· sep..table[j].
-The default value for sep is the empty string,
-the default for i is 1,
-and the default for j is the length of the table.
-If i is greater than j, returns the empty string.
-
-
-
-
-
-
-
-table.insert (table, [pos,] value)value at position pos in table,
-shifting up other elements to open space, if necessary.
-The default value for pos is n+1,
-where n is the length of the table (see §2.5.5),
-so that a call table.insert(t,x) inserts x at the end
-of table t.
-
-
-
-
-
-
-
-table.maxn (table)
-
-
-table.remove (table [, pos])table the element at position pos,
-shifting down other elements to close the space, if necessary.
-Returns the value of the removed element.
-The default value for pos is n,
-where n is the length of the table,
-so that a call table.remove(t) removes the last element
-of table t.
-
-
-
-
-
-Sorts table elements in a given order, in-place,
-from table.sort (table [, comp])table[1] to table[n],
-where n is the length of the table.
-If comp is given,
-then it must be a function that receives two table elements,
-and returns true
-when the first is less than the second
-(so that not comp(a[i+1],a[i]) will be true after the sort).
-If comp is not given,
-then the standard Lua operator < is used instead.
-
-
-5.6 - Mathematical Functions
-
-math.
-
-
-
-
-
-math.abs (x)x.
-
-
-
-
-
-
-
-math.acos (x)x (in radians).
-
-
-
-
-
-
-
-math.asin (x)x (in radians).
-
-
-
-
-
-
-
-math.atan (x)x (in radians).
-
-
-
-
-
-
-
-math.atan2 (y, x)y/x (in radians),
-but uses the signs of both parameters to find the
-quadrant of the result.
-(It also handles correctly the case of x being zero.)
-
-
-
-
-
-
-
-math.ceil (x)x.
-
-
-
-
-
-
-
-math.cos (x)x (assumed to be in radians).
-
-
-
-
-
-
-
-math.cosh (x)x.
-
-
-
-
-
-
-
-math.deg (x)x (given in radians) in degrees.
-
-
-
-
-
-
-
-math.exp (x)
-
-
-math.floor (x)x.
-
-
-
-
-
-
-
-math.fmod (x, y)x by y.
-
-
-
-
-
-
-
-math.frexp (x)m and e such that x = m2e,
-e is an integer and the absolute value of m is
-in the range [0.5, 1)
-(or zero when x is zero).
-
-
-
-
-
-
-
-math.hugeHUGE_VAL,
-a value larger than or equal to any other numerical value.
-
-
-
-
-
-
-
-math.ldexp (m, e)e should be an integer).
-
-
-
-
-
-
-
-math.log (x)x.
-
-
-
-
-
-
-
-math.log10 (x)x.
-
-
-
-
-
-
-
-math.max (x, ···)
-
-
-math.min (x, ···)
-
-
-math.modf (x)x and the fractional part of x.
-
-
-
-
-
-
-
-math.pi
-
-
-math.pow (x, y)x^y to compute this value.)
-
-
-
-
-
-
-
-math.rad (x)x (given in degrees) in radians.
-
-
-
-
-
-
-
-math.random ([m [, n]])rand provided by ANSI C.
-(No guarantees can be given for its statistical properties.)
-
-
-m,
-math.random returns
-a uniform pseudo-random integer in the range [1, m].
-When called with two integer numbers m and n,
-math.random returns a uniform pseudo-random
-integer in the range [m, n].
-
-
-
-
-
-
-
-math.randomseed (x)x as the "seed"
-for the pseudo-random generator:
-equal seeds produce equal sequences of numbers.
-
-
-
-
-
-
-
-math.sin (x)x (assumed to be in radians).
-
-
-
-
-
-
-
-math.sinh (x)x.
-
-
-
-
-
-
-
-math.sqrt (x)x.
-(You can also use the expression x^0.5 to compute this value.)
-
-
-
-
-
-
-
-math.tan (x)x (assumed to be in radians).
-
-
-
-
-
-
-
-math.tanh (x)x.
-
-
-
-
-
-
-
-5.7 - Input and Output Facilities
-
-io.
-When using explicit file descriptors,
-the operation io.open returns a file descriptor
-and then all operations are supplied as methods of the file descriptor.
-
-
-io also provides
-three predefined file descriptors with their usual meanings from C:
-io.stdin, io.stdout, and io.stderr.
-The I/O library never closes these files.
-
-
-
-
-
-io.close ([file])file:close().
-Without a file, closes the default output file.
-
-
-
-
-
-
-
-io.flush ()file:flush over the default output file.
-
-
-
-
-
-
-
-io.input ([file])
-
-
-io.lines ([filename])
- for line in io.lines(filename) do body end
-
io.lines() (with no file name) is equivalent
-to io.input():lines();
-that is, it iterates over the lines of the default input file.
-In this case it does not close the file when the loop ends.
-
-
-
-
-
-
-
-io.open (filename [, mode])mode.
-It returns a new file handle,
-or, in case of errors, nil plus an error message.
-
-
-mode string can be any of the following:
-
-
-
mode string may also have a 'b' at the end,
-which is needed in some systems to open the file in binary mode.
-This string is exactly what is used in the
-standard C function fopen.
-
-
-
-
-
-
-
-io.output ([file])io.input, but operates over the default output file.
-
-
-
-
-
-
-
-io.popen (prog [, mode])prog in a separated process and returns
-a file handle that you can use to read data from this program
-(if mode is "r", the default)
-or to write data to this program
-(if mode is "w").
-
-
-
-
-
-io.read (···)io.input():read.
-
-
-
-
-
-
-
-io.tmpfile ()
-
-
-io.type (obj)obj is a valid file handle.
-Returns the string "file" if obj is an open file handle,
-"closed file" if obj is a closed file handle,
-or nil if obj is not a file handle.
-
-
-
-
-
-
-
-io.write (···)io.output():write.
-
-
-
-
-
-
-
-file:close ()file.
-Note that files are automatically closed when
-their handles are garbage collected,
-but that takes an unpredictable amount of time to happen.
-
-
-
-
-
-
-
-file:flush ()file.
-
-
-
-
-
-
-
-file:lines ()
- for line in file:lines() do body end
-
io.lines, this function does not close the file
-when the loop ends.)
-
-
-
-
-
-
-
-file:read (···)file,
-according to the given formats, which specify what to read.
-For each format,
-the function returns a string (or a number) with the characters read,
-or nil if it cannot read data with the specified format.
-When called without formats,
-it uses a default format that reads the entire next line
-(see below).
-
-
-
-
-
-
-
-
-
-
-
-file:seek ([whence] [, offset])offset plus a base
-specified by the string whence, as follows:
-
-
-
seek returns the final file position,
-measured in bytes from the beginning of the file.
-If this function fails, it returns nil,
-plus a string describing the error.
-
-
-whence is "cur",
-and for offset is 0.
-Therefore, the call file:seek() returns the current
-file position, without changing it;
-the call file:seek("set") sets the position to the
-beginning of the file (and returns 0);
-and the call file:seek("end") sets the position to the
-end of the file, and returns its size.
-
-
-
-
-
-
-
-file:setvbuf (mode [, size])
-
-
flush the file
-(see io.flush)).
-size
-specifies the size of the buffer, in bytes.
-The default is an appropriate size.
-
-
-
-
-
-
-
-file:write (···)file.
-The arguments must be strings or numbers.
-To write other values,
-use tostring or string.format before write.
-
-
-
-
-
-
-
-5.8 - Operating System Facilities
-
-os.
-
-
-
-
-
-os.clock ()
-
-
-os.date ([format [, time]])format.
-
-
-time argument is present,
-this is the time to be formatted
-(see the os.time function for a description of this value).
-Otherwise, date formats the current time.
-
-
-format starts with '!',
-then the date is formatted in Coordinated Universal Time.
-After this optional character,
-if format is the string "*t",
-then date returns a table with the following fields:
-year (four digits), month (1--12), day (1--31),
-hour (0--23), min (0--59), sec (0--61),
-wday (weekday, Sunday is 1),
-yday (day of the year),
-and isdst (daylight saving flag, a boolean).
-
-
-format is not "*t",
-then date returns the date as a string,
-formatted according to the same rules as the C function strftime.
-
-
-date returns a reasonable date and time representation that depends on
-the host system and on the current locale
-(that is, os.date() is equivalent to os.date("%c")).
-
-
-
-
-
-
-
-os.difftime (t2, t1)t1 to time t2.
-In POSIX, Windows, and some other systems,
-this value is exactly t2-t1.
-
-
-
-
-
-
-
-os.execute ([command])system.
-It passes command to be executed by an operating system shell.
-It returns a status code, which is system-dependent.
-If command is absent, then it returns nonzero if a shell is available
-and zero otherwise.
-
-
-
-
-
-
-
-os.exit ([code])exit,
-with an optional code,
-to terminate the host program.
-The default value for code is the success code.
-
-
-
-
-
-
-
-os.getenv (varname)varname,
-or nil if the variable is not defined.
-
-
-
-
-
-
-
-os.remove (filename)
-
-
-os.rename (oldname, newname)oldname to newname.
-If this function fails, it returns nil,
-plus a string describing the error.
-
-
-
-
-
-
-
-os.setlocale (locale [, category])locale is a string specifying a locale;
-category is an optional string describing which category to change:
-"all", "collate", "ctype",
-"monetary", "numeric", or "time";
-the default category is "all".
-The function returns the name of the new locale,
-or nil if the request cannot be honored.
-
-
-locale is the empty string,
-the current locale is set to an implementation-defined native locale.
-If locale is the string "C",
-the current locale is set to the standard C locale.
-
-
-
-
-
-os.time ([table])year, month, and day,
-and may have fields hour, min, sec, and isdst
-(for a description of these fields, see the os.date function).
-
-
-time can be used only as an argument to
-date and difftime.
-
-
-
-
-
-
-
-os.tmpname ()5.9 - The Debug Library
-
-debug table.
-All functions that operate over a thread
-have an optional first argument which is the
-thread to operate over.
-The default is always the current thread.
-
-
-
-
-
-debug.debug ()cont finishes this function,
-so that the caller continues its execution.
-
-
-debug.debug are not lexically nested
-within any function, and so have no direct access to local variables.
-
-
-
-
-
-Returns the environment of object debug.getfenv (o)o.
-
-
-
-
-
-
-
-debug.gethook ([thread])debug.sethook function).
-
-
-
-
-
-
-
-debug.getinfo ([thread,] function [, what])function,
-which means the function running at level function of the call stack
-of the given thread:
-level 0 is the current function (getinfo itself);
-level 1 is the function that called getinfo;
-and so on.
-If function is a number larger than the number of active functions,
-then getinfo returns nil.
-
-
-lua_getinfo,
-with the string what describing which fields to fill in.
-The default for what is to get all information available,
-except the table of valid lines.
-If present,
-the option 'f'
-adds a field named func with the function itself.
-If present,
-the option 'L'
-adds a field named activelines with the table of
-valid lines.
-
-
-debug.getinfo(1,"n").name returns
-a table with a name for the current function,
-if a reasonable name can be found,
-and the expression debug.getinfo(print)
-returns a table with all available information
-about the print function.
-
-
-
-
-
-
-
-debug.getlocal ([thread,] level, local)local of the function at level level of the stack.
-(The first parameter or local variable has index 1, and so on,
-until the last active local variable.)
-The function returns nil if there is no local
-variable with the given index,
-and raises an error when called with a level out of range.
-(You can call debug.getinfo to check whether the level is valid.)
-
-
-(' (open parentheses)
-represent internal variables
-(loop control variables, temporaries, and C function locals).
-
-
-
-
-
-
-
-debug.getmetatable (object)object
-or nil if it does not have a metatable.
-
-
-
-
-
-
-
-debug.getregistry ()
-
-
-debug.getupvalue (func, up)up of the function func.
-The function returns nil if there is no upvalue with the given index.
-
-
-
-
-
-
-
-debug.setfenv (object, table)object to the given table.
-Returns object.
-
-
-
-
-
-
-
-debug.sethook ([thread,] hook, mask [, count])mask and the number count describe
-when the hook will be called.
-The string mask may have the following characters,
-with the given meaning:
-
-
-
"c": the hook is called every time Lua calls a function;"r": the hook is called every time Lua returns from a function;"l": the hook is called every time Lua enters a new line of code.count different from zero,
-the hook is called after every count instructions.
-
-
-debug.sethook turns off the hook.
-
-
-"call", "return" (or "tail return"),
-"line", and "count".
-For line events,
-the hook also gets the new line number as its second parameter.
-Inside a hook,
-you can call getinfo with level 2 to get more information about
-the running function
-(level 0 is the getinfo function,
-and level 1 is the hook function),
-unless the event is "tail return".
-In this case, Lua is only simulating the return,
-and a call to getinfo will return invalid data.
-
-
-
-
-
-
-
-debug.setlocal ([thread,] level, local, value)value to the local variable
-with index local of the function at level level of the stack.
-The function returns nil if there is no local
-variable with the given index,
-and raises an error when called with a level out of range.
-(You can call getinfo to check whether the level is valid.)
-Otherwise, it returns the name of the local variable.
-
-
-
-
-
-
-
-debug.setmetatable (object, table)object to the given table
-(which can be nil).
-
-
-
-
-
-
-
-debug.setupvalue (func, up, value)value to the upvalue
-with index up of the function func.
-The function returns nil if there is no upvalue
-with the given index.
-Otherwise, it returns the name of the upvalue.
-
-
-
-
-
-
-
-debug.traceback ([thread,] [message] [, level])message string is appended
-at the beginning of the traceback.
-An optional level number tells at which level
-to start the traceback
-(default is 1, the function calling traceback).
-
-
-
-
-
-
-
-6 - Lua Stand-alone
-
-lua,
-is provided with the standard distribution.
-The stand-alone interpreter includes
-all standard libraries, including the debug library.
-Its usage is:
-
-
- lua [options] [script [args]]
-
-
-e stat: executes string stat;-l mod: "requires" mod;-i: enters interactive mode after running script;-v: prints version information;--: stops handling options;-: executes stdin as a file and stops handling options.lua runs the given script,
-passing to it the given args as string arguments.
-When called without arguments,
-lua behaves as lua -v -i
-when the standard input (stdin) is a terminal,
-and as lua - otherwise.
-
-
-LUA_INIT.
-If its format is @filename,
-then lua executes the file.
-Otherwise, lua executes the string itself.
-
-
--i.
-For instance, an invocation like
-
-
- $ lua -e'a=1' -e 'print(a)' script.lua
-
a to 1, then print the value of a (which is '1'),
-and finally run the file script.lua with no arguments.
-(Here $ is the shell prompt. Your prompt may be different.)
-
-
-lua collects all arguments in the command line
-in a global table called arg.
-The script name is stored at index 0,
-the first argument after the script name goes to index 1,
-and so on.
-Any arguments before the script name
-(that is, the interpreter name plus the options)
-go to negative indices.
-For instance, in the call
-
-
- $ lua -la b.lua t1 t2
-
a.lua,
-then creates a table
-
-
- arg = { [-2] = "lua", [-1] = "-la",
- [0] = "b.lua",
- [1] = "t1", [2] = "t2" }
-b.lua.
-The script is called with arg[1], arg[2], ···
-as arguments;
-it can also access these arguments with the vararg expression '...'.
-
-
-_PROMPT contains a string,
-then its value is used as the prompt.
-Similarly, if the global variable _PROMPT2 contains a string,
-its value is used as the secondary prompt
-(issued during incomplete statements).
-Therefore, both prompts can be changed directly on the command line
-or in any Lua programs by assigning to _PROMPT.
-See the next example:
-
-
- $ lua -e"_PROMPT='myprompt> '" -i
-
-i to enter interactive mode;
-otherwise,
-the program would just end silently
-right after the assignment to _PROMPT.
-
-
-#.
-Therefore, Lua scripts can be made into executable programs
-by using chmod +x and the #! form,
-as in
-
-
- #!/usr/local/bin/lua
-
lua is in your PATH,
-then
-
-
- #!/usr/bin/env lua
-
7 - Incompatibilities with the Previous Version
-
-luaconf.h).
-However,
-all these compatibility options will be removed in the next version of Lua.
-
-
-
-7.1 - Changes in the Language
-
-
-
-
-
-
-
-arg with a
-table with the extra arguments to the vararg expression.
-(See compile-time option LUA_COMPAT_VARARG in luaconf.h.)
-[[string]])
-does not allow nesting.
-You can use the new syntax ([=[string]=]) in these cases.
-(See compile-time option LUA_COMPAT_LSTR in luaconf.h.)
-7.2 - Changes in the Libraries
-
-
-
-
-
-
-
-string.gfind was renamed string.gmatch.
-(See compile-time option LUA_COMPAT_GFIND in luaconf.h.)
-string.gsub is called with a function as its
-third argument,
-whenever this function returns nil or false the
-replacement string is the whole match,
-instead of the empty string.
-table.setn was deprecated.
-Function table.getn corresponds
-to the new length operator (#);
-use the operator instead of the function.
-(See compile-time option LUA_COMPAT_GETN in luaconf.h.)
-loadlib was renamed package.loadlib.
-(See compile-time option LUA_COMPAT_LOADLIB in luaconf.h.)
-math.mod was renamed math.fmod.
-(See compile-time option LUA_COMPAT_MOD in luaconf.h.)
-table.foreach and table.foreachi are deprecated.
-You can use a for loop with pairs or ipairs instead.
-require due to
-the new module system.
-However, the new behavior is mostly compatible with the old,
-but require gets the path from package.path instead
-of from LUA_PATH.
-collectgarbage has different arguments.
-Function gcinfo is deprecated;
-use collectgarbage("count") instead.
-7.3 - Changes in the API
-
-
-
-
-
-
-
-luaopen_* functions (to open libraries)
-cannot be called directly,
-like a regular C function.
-They must be called through Lua,
-like a Lua function.
-lua_open was replaced by lua_newstate to
-allow the user to set a memory-allocation function.
-You can use luaL_newstate from the standard library to
-create a state with a standard allocation function
-(based on realloc).
-luaL_getn and luaL_setn
-(from the auxiliary library) are deprecated.
-Use lua_objlen instead of luaL_getn
-and nothing instead of luaL_setn.
-luaL_openlib was replaced by luaL_register.
-luaL_checkudata now throws an error when the given value
-is not a userdata of the expected type.
-(In Lua 5.0 it returned NULL.)
-8 - The Complete Syntax of Lua
-
-
-
- chunk ::= {stat [`;´]} [laststat [`;´]]
-
- block ::= chunk
-
- stat ::= varlist `=´ explist |
- functioncall |
- do block end |
- while exp do block end |
- repeat block until exp |
- if exp then block {elseif exp then block} [else block] end |
- for Name `=´ exp `,´ exp [`,´ exp] do block end |
- for namelist in explist do block end |
- function funcname funcbody |
- local function Name funcbody |
- local namelist [`=´ explist]
-
- laststat ::= return [explist] | break
-
- funcname ::= Name {`.´ Name} [`:´ Name]
-
- varlist ::= var {`,´ var}
-
- var ::= Name | prefixexp `[´ exp `]´ | prefixexp `.´ Name
-
- namelist ::= Name {`,´ Name}
-
- explist ::= {exp `,´} exp
-
- exp ::= nil | false | true | Number | String | `...´ | function |
- prefixexp | tableconstructor | exp binop exp | unop exp
-
- prefixexp ::= var | functioncall | `(´ exp `)´
-
- functioncall ::= prefixexp args | prefixexp `:´ Name args
-
- args ::= `(´ [explist] `)´ | tableconstructor | String
-
- function ::= function funcbody
-
- funcbody ::= `(´ [parlist] `)´ block end
-
- parlist ::= namelist [`,´ `...´] | `...´
-
- tableconstructor ::= `{´ [fieldlist] `}´
-
- fieldlist ::= field {fieldsep field} [fieldsep]
-
- field ::= `[´ exp `]´ `=´ exp | Name `=´ exp | exp
-
- fieldsep ::= `,´ | `;´
-
- binop ::= `+´ | `-´ | `*´ | `/´ | `^´ | `%´ | `..´ |
- `<´ | `<=´ | `>´ | `>=´ | `==´ | `~=´ |
- and | or
-
- unop ::= `-´ | not | `#´
-
-
-
-
-
-Last update:
-Fri Jan 18 22:32:24 BRST 2008
-
-
-
-
-
diff --git a/engines/sword25/util/lua/doc/readme.html b/engines/sword25/util/lua/doc/readme.html
deleted file mode 100755
index 972faddd97..0000000000
--- a/engines/sword25/util/lua/doc/readme.html
+++ /dev/null
@@ -1,40 +0,0 @@
-
-
-
-
-
-
-This is the documentation included in the source distribution of Lua 5.1.3.
-
-
-
-Lua's
-official web site
-contains updated documentation,
-especially the
-reference manual.
-
-Documentation
-
-
-Last update:
-Wed Dec 19 13:59:14 BRST 2007
-
-
-
-
diff --git a/engines/sword25/util/lua/etc/Makefile b/engines/sword25/util/lua/etc/Makefile
deleted file mode 100755
index 6d00008d98..0000000000
--- a/engines/sword25/util/lua/etc/Makefile
+++ /dev/null
@@ -1,44 +0,0 @@
-# makefile for Lua etc
-
-TOP= ..
-LIB= $(TOP)/src
-INC= $(TOP)/src
-BIN= $(TOP)/src
-SRC= $(TOP)/src
-TST= $(TOP)/test
-
-CC= gcc
-CFLAGS= -O2 -Wall -I$(INC) $(MYCFLAGS)
-MYCFLAGS=
-MYLDFLAGS= -Wl,-E
-MYLIBS= -lm
-#MYLIBS= -lm -Wl,-E -ldl -lreadline -lhistory -lncurses
-RM= rm -f
-
-default:
- @echo 'Please choose a target: min noparser one strict clean'
-
-min: min.c
- $(CC) $(CFLAGS) $@.c -L$(LIB) -llua $(MYLIBS)
- echo 'print"Hello there!"' | ./a.out
-
-noparser: noparser.o
- $(CC) noparser.o $(SRC)/lua.o -L$(LIB) -llua $(MYLIBS)
- $(BIN)/luac $(TST)/hello.lua
- -./a.out luac.out
- -./a.out -e'a=1'
-
-one:
- $(CC) $(CFLAGS) all.c $(MYLIBS)
- ./a.out $(TST)/hello.lua
-
-strict:
- -$(BIN)/lua -e 'print(a);b=2'
- -$(BIN)/lua -lstrict -e 'print(a)'
- -$(BIN)/lua -e 'function f() b=2 end f()'
- -$(BIN)/lua -lstrict -e 'function f() b=2 end f()'
-
-clean:
- $(RM) a.out core core.* *.o luac.out
-
-.PHONY: default min noparser one strict clean
diff --git a/engines/sword25/util/lua/etc/README b/engines/sword25/util/lua/etc/README
deleted file mode 100755
index 5149fc91d4..0000000000
--- a/engines/sword25/util/lua/etc/README
+++ /dev/null
@@ -1,37 +0,0 @@
-This directory contains some useful files and code.
-Unlike the code in ../src, everything here is in the public domain.
-
-If any of the makes fail, you're probably not using the same libraries
-used to build Lua. Set MYLIBS in Makefile accordingly.
-
-all.c
- Full Lua interpreter in a single file.
- Do "make one" for a demo.
-
-lua.hpp
- Lua header files for C++ using 'extern "C"'.
-
-lua.ico
- A Lua icon for Windows (and web sites: save as favicon.ico).
- Drawn by hand by Markus Gritsch