Lua Globals
Lua Globals
The following is a list of functions and variables that are native to Lua. These functions can be used in a standard installation of Lua 5.1.4, though there are some differences in how some of these work on Roblox.
Functions
Variant assert ( Variant value, string errorMessage = "assertion failed!" ) |
Throws an error if the provided
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Variant collectgarbage ( string operation ) |
Performs an operation on the Lua garbage collector based on the specified option. Roblox’s Lua sandbox only allows the “count” option to be used, so none of the other standard options are available. The “count” option returns the total memory in use by Lua (in kilobytes). |
void error ( string message, int level = 1 ) |
Terminates the last protected function called and outputs message as an error message. If the function containing the error is not called in a protected function (pcall), then the script which called the function will terminate. The error function itself never returns and acts like a script error. 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. |
table getfenv ( Variant stack = 1 ) |
Returns the current environment in use by the caller.
UsageGetting the Current Environment
Getting the Environment of a Function
Getting the Environment Based on Stack
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Variant getmetatable ( Variant t ) |
Returns the metatable of the given table
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function , array , int ipairs ( array t ) |
Returns three values: an iterator function, the table t and the number 0. Each time the iterator function is called, it returns the next numerical index-value pair in the table. When used in a generic for-loop, the return values can be used to iterate over each numerical index in the table:
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Variant loadstring ( string contents ) |
Loads Lua code from a string, and returns it as a function. Unlike standard Lua 5.1, Roblox’s Lua cannot load the binary version of Lua using loadstring. |
userdata newproxy ( bool addMetatable = false ) |
Creates a blank |
Variant , Variant next ( table t, Variant lastKey = nil ) |
Returns the first key/value pair in the array. If a lastKey argument was specified then returns the next element in the array based on the key that provided. 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 loop or 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. |
function , table pairs ( table t ) |
Returns an iterator function, the passed table t and nil, so that the construction will iterate over all key/value pairs of that table when used in a generic for-loop:
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bool , Variant pcall ( function func, Tuple args ) |
Calls the function func with the given arguments in protected mode. This means that any error inside func 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. |
void print ( Tuple params ) |
Receives any number of arguments, and prints their values to the output. |
bool rawequal ( Variant v1, Variant v2 ) |
Checks whether v1 is equal to v2, without invoking any metamethod. |
Variant rawget ( table t, Variant index ) |
Gets the real value of table[index], without invoking any metamethod. |
table rawset ( table t, Variant index, Variant value ) |
Sets the real value of table[index] to a given value, without invoking any metamethod. |
Tuple select ( int index, Tuple args ) |
Returns all arguments after argument number index. If negative, it will return from the end of the argument list.
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int select ( string cmd, Tuple args ) |
Returns the total number of arguments that were passed after the
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Variant setfenv ( Variant f, table fenv ) |
Sets the environment to be used by the given function. f can be a 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. |
table setmetatable ( table t, Variant newMeta ) |
Sets the metatable for the given table
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Variant tonumber ( Variant arg, int base = 10 ) |
Attempts to convert the arg into a number with a specified base to interpret the value in. If it cannot be converted, this function returns nil. 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. In other bases, only unsigned integers are accepted. If a string begins with “0x” and a base is not provided, the 0x is trimmed and the base is assumed to be 16, or hexadecimal.
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string tostring ( Variant e ) |
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 string.format. If the metatable of
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string type ( Variant v ) |
Returns the type of its only argument, coded as a string. The possible results of this function are “nil” (a string, not the value nil), “number”, “string”, “boolean”, “table”, “function”, “thread”, and “userdata”. |
Variant unpack ( table list, int i = 1, int j = #list ) |
Returns the elements from the given table. By default, i is 1 and j is the length of list, as defined by the length operator. |
bool , Variant xpcall ( function f, function err, tuple args ) |
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, and passes a list of arguments. 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. |
Variables
array _G |
A table that is shared between all scripts of the same context level. |
string _VERSION |
A global variable (not a function) that holds a string containing the current interpreter version. |