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diff --git a/doc/manual.html b/doc/manual.html index 5ed8f069..8cdeacfd 100644 --- a/doc/manual.html +++ b/doc/manual.html @@ -1,39 +1,41 @@ <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> -<html> - -<head> -<title>Lua 5.3 Reference Manual</title> -<link rel="stylesheet" type="text/css" href="lua.css"> -<link rel="stylesheet" type="text/css" href="manual.css"> +<HTML> +<HEAD> +<TITLE>Lua 5.3 Reference Manual</TITLE> +<LINK REL="stylesheet" TYPE="text/css" HREF="lua.css"> +<LINK REL="stylesheet" TYPE="text/css" HREF="manual.css"> <META HTTP-EQUIV="content-type" CONTENT="text/html; charset=iso-8859-1"> -</head> +</HEAD> -<body> +<BODY> -<hr> -<h1> -<a href="http://www.lua.org/"><img src="logo.gif" alt="" border="0"></a> +<H1> +<A HREF="http://www.lua.org/"><IMG SRC="logo.gif" ALT="Lua"></A> Lua 5.3 Reference Manual -</h1> +</H1> +<P> by Roberto Ierusalimschy, Luiz Henrique de Figueiredo, Waldemar Celes -<p> -<small> + +<P> +<SMALL> Copyright © 2015 Lua.org, PUC-Rio. Freely available under the terms of the <a href="http://www.lua.org/license.html">Lua license</a>. -</small> -<hr> -<p> +</SMALL> -<a href="contents.html#contents">contents</A> +<DIV CLASS="menubar"> +<A HREF="contents.html#contents">contents</A> +· +<A HREF="contents.html#index">index</A> · -<a href="contents.html#index">index</A> +<A HREF="http://www.lua.org/manual/">other versions</A> +</DIV> <!-- ====================================================================== --> <p> -<!-- $Id: manual.of,v 1.146 2015/01/06 11:23:01 roberto Exp $ --> +<!-- $Id: manual.of,v 1.149 2015/06/02 19:27:17 roberto Exp $ --> @@ -113,15 +115,15 @@ There are eight basic types in Lua: <em>nil</em>, <em>boolean</em>, <em>number</em>, <em>string</em>, <em>function</em>, <em>userdata</em>, <em>thread</em>, and <em>table</em>. -<em>Nil</em> is the type of the value <b>nil</b>, +The type <em>nil</em> has one single value, <b>nil</b>, whose main property is to be different from any other value; it usually represents the absence of a useful value. -<em>Boolean</em> is the type of the values <b>false</b> and <b>true</b>. +The type <em>boolean</em> has two values, <b>false</b> and <b>true</b>. Both <b>nil</b> and <b>false</b> make a condition false; any other value makes it true. -<em>Number</em> represents both +The type <em>number</em> represents both integer numbers and real (floating-point) numbers. -<em>String</em> represents immutable sequences of bytes. +The type <em>string</em> represents immutable sequences of bytes. Lua is 8-bit clean: strings can contain any 8-bit value, @@ -132,6 +134,7 @@ it makes no assumptions about the contents of a string. <p> The type <em>number</em> uses two internal representations, +or two subtypes, one called <em>integer</em> and the other called <em>float</em>. Lua has explicit rules about when each representation is used, but it also converts between them automatically as needed (see <a href="#3.4.3">§3.4.3</a>). @@ -142,7 +145,7 @@ or to assume complete control over the representation of each number. Standard Lua uses 64-bit integers and double-precision (64-bit) floats, but you can also compile Lua so that it uses 32-bit integers and/or single-precision (32-bit) floats. -The option with 32 bits for both integers and floats +The option with 32 bits for both integers and floats is particularly attractive for small machines and embedded systems. (See macro <code>LUA_32BITS</code> in file <code>luaconf.h</code>.) @@ -185,8 +188,8 @@ even those that do not support threads natively. The type <em>table</em> implements associative arrays, that is, arrays that can be indexed not only with numbers, but with any Lua value except <b>nil</b> and NaN. -(<em>Not a Number</em> is a special numeric value used to represent -undefined or unrepresentable results, such as <code>0/0</code>.) +(<em>Not a Number</em> is a special numerical value used to represent +undefined or unrepresentable numerical results, such as <code>0/0</code>.) Tables can be <em>heterogeneous</em>; that is, they can contain values of all types (except <b>nil</b>). Any key with value <b>nil</b> is not considered part of the table. @@ -207,7 +210,7 @@ There are several convenient ways to create tables in Lua <p> We use the term <em>sequence</em> to denote a table where -the set of all positive numeric keys is equal to {1..<em>n</em>} +the set of all positive numerical keys is equal to {1..<em>n</em>} for some non-negative integer <em>n</em>, which is called the length of the sequence (see <a href="#3.4.7">§3.4.7</a>). @@ -372,7 +375,7 @@ 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, +For instance, when a non-numerical value is the operand of an addition, Lua checks for a function in the field "<code>__add</code>" of the value's metatable. If it finds one, Lua calls this function to perform the addition. @@ -393,7 +396,7 @@ using the <a href="#pdf-getmetatable"><code>getmetatable</code></a> function. <p> You can replace the metatable of tables using the <a href="#pdf-setmetatable"><code>setmetatable</code></a> function. -You cannot change the metatable of other types from Lua +You cannot change the metatable of other types from Lua code (except by using the debug library (<a href="#6.10">§6.10</a>)); you must use the C API for that. @@ -425,12 +428,7 @@ for instance, the key for operation "add" is the string "<code>__add</code>". Note that queries for metamethods are always raw; the access to a metamethod does not invoke other metamethods. -You can emulate how Lua queries a metamethod for an object <code>obj</code> -with the following code: -<pre> - rawget(getmetatable(obj) or {}, "__" .. event_name) -</pre> <p> For the unary operators (negation, length, and bitwise not), @@ -510,7 +508,7 @@ the <code>&</code> (bitwise and) operation. Behavior similar to the "add" operation, except that Lua will try a metamethod -if any operator is neither an integer +if any operand is neither an integer nor a value coercible to an integer (see <a href="#3.4.3">§3.4.3</a>). </li> @@ -549,7 +547,7 @@ the <code>..</code> (concatenation) operation. Behavior similar to the "add" operation, except that Lua will try a metamethod -if any operator is neither a string nor a number +if any operand is neither a string nor a number (which is always coercible to a string). </li> @@ -599,6 +597,8 @@ then it will try the "<code>__lt</code>" event, assuming that <code>a <= b</code> is equivalent to <code>not (b < a)</code>. As with the other comparison operators, the result is always a boolean. +(This use of the "<code>__lt</code>" event can be removed in future versions; +it is also slower than a real "<code>__le</code>" metamethod.) </li> <li><b>"index": </b> @@ -661,6 +661,13 @@ followed by the arguments of the original call (<code>args</code>). </ul> +<p> +It is a good practice to add all needed metamethods to a table +before setting it as a metatable of some object. +In particular, the "<code>__gc</code>" metamethod works only when this order +is followed (see <a href="#2.5.1">§2.5.1</a>). + + @@ -752,8 +759,6 @@ and the metatable has a field indexed by the string "<code>__gc</code>". Note that if you set a metatable without a <code>__gc</code> field and later create that field in the metatable, the object will not be marked for finalization. -However, after an object has been marked, -you can freely change the <code>__gc</code> field of its metatable. <p> @@ -794,7 +799,7 @@ Moreover, if the finalizer marks a finalizing object for finalization again, its finalizer will be called again in the next cycle where the object is unreachable. In any case, -the object memory is freed only in the GC cycle where +the object memory is freed only in a GC cycle where the object is unreachable and not marked for finalization. @@ -822,8 +827,8 @@ then the garbage collector will collect that object. <p> 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 weak values allows the collection of its values, +but prevents the collection of its keys. 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, @@ -913,10 +918,10 @@ You execute a coroutine by calling <a href="#pdf-coroutine.resume"><code>corouti When you first call <a href="#pdf-coroutine.resume"><code>coroutine.resume</code></a>, passing as its first argument a thread returned by <a href="#pdf-coroutine.create"><code>coroutine.create</code></a>, -the coroutine starts its execution, -at the first line of its main function. +the coroutine starts its execution by +calling its main function. Extra arguments passed to <a href="#pdf-coroutine.resume"><code>coroutine.resume</code></a> are passed -as arguments to the coroutine's main function. +as arguments to that function. After the coroutine starts running, it runs until it terminates or <em>yields</em>. @@ -1195,7 +1200,7 @@ which start with <code>0x</code> or <code>0X</code>. Hexadecimal constants also accept an optional fractional part plus an optional binary exponent, marked by a letter '<code>p</code>' or '<code>P</code>'. -A numeric constant with a fractional dot or an exponent +A numerical constant with a fractional dot or an exponent denotes a float; otherwise it denotes an integer. Examples of valid integer constants are @@ -1581,11 +1586,11 @@ because now <b>return</b> is the last statement in its (inner) block. <p> The <b>for</b> statement has two forms: -one numeric and one generic. +one numerical and one generic. <p> -The numeric <b>for</b> loop repeats a block of code while a +The numerical <b>for</b> loop repeats a block of code while a control variable runs through an arithmetic progression. It has the following syntax: @@ -1879,13 +1884,13 @@ so that it works for non-integer exponents too. <p> Floor division (<code>//</code>) is a division -that rounds the quotient towards minus infinite, +that rounds the quotient towards minus infinity, that is, the floor of the division of its operands. <p> Modulo is defined as the remainder of a division -that rounds the quotient towards minus infinite (floor division). +that rounds the quotient towards minus infinity (floor division). <p> @@ -1972,8 +1977,9 @@ The conversion from strings to numbers goes as follows: First, the string is converted to an integer or a float, following its syntax and the rules of the Lua lexer. (The string may have also leading and trailing spaces and a sign.) -Then, the resulting number is converted to the required type -(float or integer) according to the previous rules. +Then, the resulting number (float or integer) +is converted to the type (float or integer) required by the context +(e.g., the operation that forced the conversion). <p> @@ -2006,11 +2012,7 @@ Equality (<code>==</code>) first compares the type of its operands. If the types are different, then the result is <b>false</b>. Otherwise, the values of the operands are compared. Strings are compared in the obvious way. -Numbers follow the usual rule for binary operations: -if both operands are integers, -they are compared as integers; -otherwise, they are converted to floats -and compared as such. +Numbers are equal if they denote the same mathematical value. <p> @@ -2045,8 +2047,8 @@ The operator <code>~=</code> is exactly the negation of equality (<code>==</code <p> The order operators work as follows. If both arguments are numbers, -then they are compared following -the usual rule for binary operations. +then they are compared according to their mathematical values +(regardless of their subtypes). 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" @@ -2055,6 +2057,12 @@ A comparison <code>a > b</code> is translated to <code>b < a</code> and <code>a >= b</code> is translated to <code>b <= a</code>. +<p> +Following the IEEE 754 standard, +NaN is considered neither smaller than, +nor equal to, nor greater than any value (including itself). + + @@ -2126,7 +2134,7 @@ Unless a <code>__len</code> metamethod is given, the length of a table <code>t</code> is only defined if the table is a <em>sequence</em>, that is, -the set of its positive numeric keys is equal to <em>{1..n}</em> +the set of its positive numerical keys is equal to <em>{1..n}</em> for some non-negative integer <em>n</em>. In that case, <em>n</em> is its length. Note that a table like @@ -2137,8 +2145,8 @@ Note that a table like is not a sequence, because it has the key <code>4</code> but does not have the key <code>3</code>. (So, there is no <em>n</em> such that the set <em>{1..n}</em> is equal -to the set of positive numeric keys of that table.) -Note, however, that non-numeric keys do not interfere +to the set of positive numerical keys of that table.) +Note, however, that non-numerical keys do not interfere with whether a table is a sequence. @@ -2636,29 +2644,22 @@ works only with <em>valid indices</em> or <em>acceptable indices</em>. <p> A <em>valid index</em> is an index that refers to a -real position within the stack, that is, -its position lies between 1 and the stack top -(<code>1 ≤ abs(index) ≤ top</code>). - -Usually, functions that can modify the value at an index -require valid indices. - - -<p> -Unless otherwise noted, -any function that accepts valid indices also accepts <em>pseudo-indices</em>, -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 registry +position that stores a modifiable Lua value. +It comprises stack indices between 1 and the stack top +(<code>1 ≤ abs(index) ≤ top</code>) + +plus <em>pseudo-indices</em>, +which represent some positions that are accessible to C code +but that are not in the stack. +Pseudo-indices are used to access the registry (see <a href="#4.5">§4.5</a>) and the upvalues of a C function (see <a href="#4.4">§4.4</a>). <p> -Functions that do not need a specific stack position, -but only a value in the stack (e.g., query functions), +Functions that do not need a specific mutable position, +but only a value (e.g., query functions), can be called with acceptable indices. An <em>acceptable index</em> can be any valid index, -including the pseudo-indices, but it also can be any positive index after the stack top within the space allocated for the stack, that is, indices up to the stack size. @@ -2701,7 +2702,7 @@ Whenever a C function is called, its upvalues are located at specific pseudo-indices. These pseudo-indices are produced by the macro <a href="#lua_upvalueindex"><code>lua_upvalueindex</code></a>. -The first value associated with a function is at position +The first upvalue associated with a function is at index <code>lua_upvalueindex(1)</code>, and so on. Any access to <code>lua_upvalueindex(<em>n</em>)</code>, where <em>n</em> is greater than the number of upvalues of the @@ -2719,8 +2720,7 @@ Lua provides a <em>registry</em>, a predefined table that can be used by any C code to store whatever Lua values it needs to store. The registry table is always located at pseudo-index -<a name="pdf-LUA_REGISTRYINDEX"><code>LUA_REGISTRYINDEX</code></a>, -which is a valid index. +<a name="pdf-LUA_REGISTRYINDEX"><code>LUA_REGISTRYINDEX</code></a>. Any C library can store data into this table, but it must take care to choose keys that are different from those used @@ -2981,7 +2981,8 @@ tells whether the function may raise errors: <pre>int lua_absindex (lua_State *L, int idx);</pre> <p> -Converts the acceptable index <code>idx</code> into an absolute index +Converts the acceptable index <code>idx</code> +into an equivalent absolute index (that is, one that does not depend on the stack top). @@ -3661,7 +3662,7 @@ By default this type is <code>long long</code>, (usually a 64-bit two-complement integer), but that can be changed to <code>long</code> or <code>int</code> (usually a 32-bit two-complement integer). -(See <code>LUA_INT</code> in <code>luaconf.h</code>.) +(See <code>LUA_INT_TYPE</code> in <code>luaconf.h</code>.) <p> @@ -4068,7 +4069,7 @@ the table during its traversal. <hr><h3><a name="lua_Number"><code>lua_Number</code></a></h3> -<pre>typedef double lua_Number;</pre> +<pre>typedef ... lua_Number;</pre> <p> The type of floats in Lua. @@ -4076,8 +4077,8 @@ The type of floats in Lua. <p> By default this type is double, -but that can be changed to a single float. -(See <code>LUA_REAL</code> in <code>luaconf.h</code>.) +but that can be changed to a single float or a long double. +(See <code>LUA_FLOAT_TYPE</code> in <code>luaconf.h</code>.) @@ -4133,7 +4134,7 @@ then the error message returned on the stack is exactly the original error message. Otherwise, <code>msgh</code> is the stack index of a <em>message handler</em>. -(In the current implementation, this index cannot be a pseudo-index.) +(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 @@ -4267,20 +4268,11 @@ when called, invokes the corresponding C function. <p> -Any function to be registered in Lua must +Any function to be callable by Lua must follow the correct protocol to receive its parameters and return its results (see <a href="#lua_CFunction"><code>lua_CFunction</code></a>). -<p> -<code>lua_pushcfunction</code> is defined as a macro: - -<pre> - #define lua_pushcfunction(L,f) lua_pushcclosure(L,f,0) -</pre><p> -Note that <code>f</code> is used twice. - - @@ -4309,7 +4301,7 @@ The conversion specifiers can only be '<code>%%</code>' (inserts the character '<code>%</code>'), '<code>%s</code>' (inserts a zero-terminated string, with no size restrictions), '<code>%f</code>' (inserts a <a href="#lua_Number"><code>lua_Number</code></a>), -'<code>%L</code>' (inserts a <a href="#lua_Integer"><code>lua_Integer</code></a>), +'<code>%I</code>' (inserts a <a href="#lua_Integer"><code>lua_Integer</code></a>), '<code>%p</code>' (inserts a pointer as a hexadecimal numeral), '<code>%d</code>' (inserts an <code>int</code>), '<code>%c</code>' (inserts an <code>int</code> as a one-byte character), and @@ -4369,9 +4361,8 @@ light userdata with the same C address. <pre>const char *lua_pushliteral (lua_State *L, const char *s);</pre> <p> -This macro is equivalent to <a href="#lua_pushlstring"><code>lua_pushlstring</code></a>, -but can be used only when <code>s</code> is a literal string. -It automatically provides the string length. +This macro is equivalent to <a href="#lua_pushstring"><code>lua_pushstring</code></a>, +but should be used only when <code>s</code> is a literal string. @@ -4598,9 +4589,9 @@ that is, it does not invoke metamethods. <pre>void lua_rawsetp (lua_State *L, int index, const void *p);</pre> <p> -Does the equivalent of <code>t[k] = v</code>, +Does the equivalent of <code>t[p] = v</code>, where <code>t</code> is the table at the given index, -<code>k</code> is the pointer <code>p</code> represented as a light userdata, +<code>p</code> is encoded as a light userdata, and <code>v</code> is the value at the top of the stack. @@ -4672,7 +4663,7 @@ because a pseudo-index is not an actual stack position. <p> Moves the top element into the given valid index without shifting any element -(therefore replacing the value at the given index), +(therefore replacing the value at that given index), and then pops the top element. @@ -4684,7 +4675,7 @@ and then pops the top element. <pre>int lua_resume (lua_State *L, lua_State *from, int nargs);</pre> <p> -Starts and resumes a coroutine in a given thread. +Starts and resumes a coroutine in the given thread <code>L</code>. <p> @@ -4731,12 +4722,16 @@ this parameter can be <code>NULL</code>. <pre>void lua_rotate (lua_State *L, int idx, int n);</pre> <p> -Rotates the stack elements from <code>idx</code> to the top <code>n</code> positions -in the direction of the top, for a positive <code>n</code>, +Rotates the stack elements between the valid index <code>idx</code> +and the top of the stack. +The elements are rotated <code>n</code> positions in the direction of the top, +for a positive <code>n</code>, or <code>-n</code> positions in the direction of the bottom, for a negative <code>n</code>. The absolute value of <code>n</code> must not be greater than the size of the slice being rotated. +This function cannot be called with a pseudo-index, +because a pseudo-index is not an actual stack position. @@ -5072,7 +5067,7 @@ There is no way to convert the pointer back to its original value. <p> -Typically this function is used only for debug information. +Typically this function is used only for hashing and debug information. @@ -5127,7 +5122,7 @@ Returns the type of the value in the given valid index, or <code>LUA_TNONE</code> for a non-valid (but acceptable) index. The types returned by <a href="#lua_type"><code>lua_type</code></a> are coded by the following constants defined in <code>lua.h</code>: -<a name="pdf-LUA_TNIL"><code>LUA_TNIL</code></a>, +<a name="pdf-LUA_TNIL"><code>LUA_TNIL</code></a> (0), <a name="pdf-LUA_TNUMBER"><code>LUA_TNUMBER</code></a>, <a name="pdf-LUA_TBOOLEAN"><code>LUA_TBOOLEAN</code></a>, <a name="pdf-LUA_TSTRING"><code>LUA_TSTRING</code></a>, @@ -5618,24 +5613,26 @@ it returns 0. <pre>const char *lua_getupvalue (lua_State *L, int funcindex, int n);</pre> <p> -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.) -<a href="#lua_getupvalue"><code>lua_getupvalue</code></a> gets the index <code>n</code> of an upvalue, -pushes the upvalue's value onto the stack, +Gets information about the <code>n</code>-th upvalue +of the closure at index <code>funcindex</code>. +It pushes the upvalue's value onto the stack and returns its name. -<code>funcindex</code> 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 <code>NULL</code> (and pushes nothing) +when the index <code>n</code> is greater than the number of upvalues. <p> -Returns <code>NULL</code> (and pushes nothing) -when the index is greater than the number of upvalues. For C functions, this function uses the empty string <code>""</code> as a name for all upvalues. +(For Lua functions, +upvalues are the external local variables that the function uses, +and that are consequently included in its closure.) + + +<p> +Upvalues have no particular order, +as they are active through the whole function. +They are numbered in an arbitrary order. @@ -5680,10 +5677,10 @@ that is, they cannot call <a href="#lua_yieldk"><code>lua_yieldk</code></a>, <p> Hook functions can yield under the following conditions: -Only count and line events can yield -and they cannot yield any value; -to yield a hook function must finish its execution -calling <a href="#lua_yield"><code>lua_yield</code></a> with <code>nresults</code> equal to zero. +Only count and line events can yield; +to yield, a hook function must finish its execution +calling <a href="#lua_yield"><code>lua_yield</code></a> with <code>nresults</code> equal to zero +(that is, with no values). @@ -5748,9 +5745,7 @@ A hook is disabled by setting <code>mask</code> to zero. <p> Sets the value of a local variable of a given activation record. -Parameters <code>ar</code> and <code>n</code> are as in <a href="#lua_getlocal"><code>lua_getlocal</code></a> -(see <a href="#lua_getlocal"><code>lua_getlocal</code></a>). -<a href="#lua_setlocal"><code>lua_setlocal</code></a> assigns the value at the top of the stack +It assigns the value at the top of the stack to the variable and returns its name. It also pops the value from the stack. @@ -5761,6 +5756,10 @@ when the index is greater than the number of active local variables. +<p> +Parameters <code>ar</code> and <code>n</code> are as in function <a href="#lua_getlocal"><code>lua_getlocal</code></a>. + + @@ -5773,13 +5772,15 @@ 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 <code>funcindex</code> and <code>n</code> are as in the <a href="#lua_getupvalue"><code>lua_getupvalue</code></a> -(see <a href="#lua_getupvalue"><code>lua_getupvalue</code></a>). <p> Returns <code>NULL</code> (and pops nothing) -when the index is greater than the number of upvalues. +when the index <code>n</code> is greater than the number of upvalues. + + +<p> +Parameters <code>funcindex</code> and <code>n</code> are as in function <a href="#lua_getupvalue"><code>lua_getupvalue</code></a>. @@ -5792,9 +5793,6 @@ when the index is greater than the number of upvalues. <p> Returns a unique identifier for the upvalue numbered <code>n</code> from the closure at index <code>funcindex</code>. -Parameters <code>funcindex</code> and <code>n</code> are as in the <a href="#lua_getupvalue"><code>lua_getupvalue</code></a> -(see <a href="#lua_getupvalue"><code>lua_getupvalue</code></a>) -(but <code>n</code> cannot be greater than the number of upvalues). <p> @@ -5805,6 +5803,11 @@ Lua closures that share an upvalue will return identical ids for those upvalue indices. +<p> +Parameters <code>funcindex</code> and <code>n</code> are as in function <a href="#lua_getupvalue"><code>lua_getupvalue</code></a>, +but <code>n</code> cannot be greater than the number of upvalues. + + @@ -6367,9 +6370,9 @@ pushes nothing and returns <code>LUA_TNIL</code>. <p> Pushes onto the stack the metatable associated with name <code>tname</code> -in the registry (see <a href="#luaL_newmetatable"><code>luaL_newmetatable</code></a>). -If there is no metatable associated with <code>tname</code>, -returns false and pushes <b>nil</b>. +in the registry (see <a href="#luaL_newmetatable"><code>luaL_newmetatable</code></a>) +(<b>nil</b> if there is no metatable associated with that name). +Returns the type of the pushed value. @@ -7332,8 +7335,8 @@ you can use <code>next(t)</code> to check whether a table is empty. <p> The order in which the indices are enumerated is not specified, -<em>even for numeric indices</em>. -(To traverse a table in numeric order, +<em>even for numerical indices</em>. +(To traverse a table in numerical order, use a numerical <b>for</b>.) @@ -7522,8 +7525,6 @@ the function returns <b>nil</b>. <hr><h3><a name="pdf-tostring"><code>tostring (v)</code></a></h3> Receives a value of any type and converts it to a string in a human-readable format. -Floats always produce strings with some -floating-point indication (either a decimal dot or an exponent). (For complete control of how numbers are converted, use <a href="#pdf-string.format"><code>string.format</code></a>.) @@ -7579,8 +7580,8 @@ except that it sets a new message handler <code>msgh</code>. <h2>6.2 – <a name="6.2">Coroutine Manipulation</a></h2> <p> -The operations related to coroutines comprise a sub-library of -the basic library and come inside the table <a name="pdf-coroutine"><code>coroutine</code></a>. +This library comprise the operations to manipulate coroutines, +which come inside the table <a name="pdf-coroutine"><code>coroutine</code></a>. See <a href="#2.6">§2.6</a> for a general description of coroutines. @@ -7590,7 +7591,7 @@ See <a href="#2.6">§2.6</a> for a general description of coroutines. <p> Creates a new coroutine, with body <code>f</code>. -<code>f</code> must be a Lua function. +<code>f</code> must be a function. Returns this new coroutine, an object with type <code>"thread"</code>. @@ -7674,7 +7675,7 @@ or if it has stopped with an error. <p> Creates a new coroutine, with body <code>f</code>. -<code>f</code> must be a Lua function. +<code>f</code> must be a 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 <code>resume</code>. @@ -8186,18 +8187,23 @@ may produce the string: <p> Options -<code>A</code> and <code>a</code> (when available), -<code>E</code>, <code>e</code>, <code>f</code>, +<code>A</code>, <code>a</code>, <code>E</code>, <code>e</code>, <code>f</code>, <code>G</code>, and <code>g</code> all expect a number as argument. Options <code>c</code>, <code>d</code>, <code>i</code>, <code>o</code>, <code>u</code>, <code>X</code>, and <code>x</code> expect an integer. -Option <code>q</code> expects a string; -option <code>s</code> expects a string without embedded zeros. -If the argument to option <code>s</code> is not a string, +Option <code>q</code> expects a string. +Option <code>s</code> expects a string without embedded zeros; +if its argument is not a string, it is converted to one following the same rules of <a href="#pdf-tostring"><code>tostring</code></a>. +<p> +When Lua is compiled with a non-C99 compiler, +options <code>A</code> and <code>a</code> (hexadecimal floats) +do not support any modifier (flags, width, length). + + <p> @@ -8859,7 +8865,7 @@ It provides all its functions inside the table <a name="pdf-table"><code>table</ Remember that, whenever an operation needs the length of a table, the table must be a proper sequence or have a <code>__len</code> metamethod (see <a href="#3.4.7">§3.4.7</a>). -All functions ignore non-numeric keys +All functions ignore non-numerical keys in the tables given as arguments. @@ -8904,7 +8910,7 @@ multiple assignment: <code>a2[t],··· = a1[f],···,a1[e]</code>. The default for <code>a2</code> is <code>a1</code>. The destination range can overlap with the source range. -Index <code>f</code> must be positive. +The number of elements to be moved must fit in a Lua integer. @@ -9946,17 +9952,26 @@ because of its reliance on C function <code>setlocale</code>. <p> Returns the current time when called without arguments, -or a time representing the date and time specified by the given table. +or a time representing the local date and time specified by the given table. This table must have fields <code>year</code>, <code>month</code>, and <code>day</code>, and may have fields <code>hour</code> (default is 12), <code>min</code> (default is 0), <code>sec</code> (default is 0), and <code>isdst</code> (default is <b>nil</b>). +Other fields are ignored. For a description of these fields, see the <a href="#pdf-os.date"><code>os.date</code></a> function. <p> +The values in these fields do not need to be inside their valid ranges. +For instance, if <code>sec</code> is -10, +it means -10 seconds from the time specified by the other fields; +if <code>hour</code> is 1000, +it means +1000 hours from the time specified by the other fields. + + +<p> The returned value is a number, whose meaning depends on your system. In POSIX, Windows, and some other systems, this number counts the number @@ -10093,7 +10108,7 @@ valid lines. <p> For instance, the expression <code>debug.getinfo(1,"n").name</code> returns -a table with a name for the current function, +a name for the current function, if a reasonable name can be found, and the expression <code>debug.getinfo(print)</code> returns a table with all available information @@ -10520,7 +10535,7 @@ all these compatibility options will be removed in the future. <p> Lua versions can always change the C API in ways that do not imply source-code changes in a program, -such as the numeric values for constants +such as the numerical values for constants or the implementation of functions as macros. Therefore, you should not assume that binaries are compatible between @@ -10599,7 +10614,8 @@ The <code>bit32</code> library has been deprecated. It is easy to require a compatible external library or, better yet, to replace its functions with appropriate bitwise operations. (Keep in mind that <code>bit32</code> operates on 32-bit integers, -while the bitwise operators in standard Lua operate on 64-bit integers.) +while the bitwise operators in Lua 5.3 operate on Lua integers, +which by default have 64 bits.) </li> <li> @@ -10614,7 +10630,7 @@ its <code>__ipairs</code> metamethod has been deprecated. <li> Option names in <a href="#pdf-io.read"><code>io.read</code></a> do not have a starting '<code>*</code>' anymore. -For compatibility, Lua will continue to ignore this character. +For compatibility, Lua will continue to accept (and ignore) this character. </li> <li> @@ -10641,6 +10657,12 @@ if it cannot find an open function according to the new style. but it did not document the change.) </li> +<li> +The call <code>collectgarbage("count")</code> now returns only one result. +(You can compute that second result from the fractional part +of the first result.) +</li> + </ul> @@ -10776,13 +10798,12 @@ and LiteralString, see <a href="#3.1">§3.1</a>.) -<HR> -<SMALL CLASS="footer"> +<P CLASS="footer"> Last update: -Tue Jan 6 10:10:50 BRST 2015 -</SMALL> +Wed Jun 3 08:27:47 BRT 2015 +</P> <!-- -Last change: revised for Lua 5.3.0 (final) +Last change: revised for Lua 5.3.1 --> </body></html> |