LuaGlobals.yaml

name: Lua Globals
type: global
summary: |
  A list of functions and variables that are native to Lua.
description: |
  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](https://www.lua.org/manual/5.1/), though there are some
  differences in how some of these work on Roblox.
code_samples:
properties:
  - name: _G
    type: Array
    summary: |
      A table that is shared between all scripts of the same context level.
    description: |
      A table that is shared between all scripts of the same context level.
    tags:
    code_samples:
  - name: _VERSION
    type: string
    summary: |
      A global variable that holds a string containing the current interpreter
      version.
    description: |
      A global variable (not a function) that holds a string containing the
      current interpreter version.
    tags:
    code_samples:
functions:
  - name: assert
    summary: |
      Throws an error if the provided `value` resolves to `false` or `nil`.
    description: |
      Throws an error if the provided `value` is `false` or `nil`. If the
      assertion passes, it returns all values passed to it.

      ```lua
      local product = 90 * 4
      assert(product == 360, "Oh dear, multiplication is broken")
      -- The line above does nothing, because 90 times 4 is 360
      ```
    parameters:
      - name: value
        type: Variant
        default:
        summary: |
          The value that will be asserted against.
      - name: errorMessage
        type: string
        default: assertion failed!
        summary: |
          The text that will be shown in the error if the assertion fails.
    returns:
      - type: Variant
        summary: ''
    tags:
    code_samples:
  - name: collectgarbage
    summary: |
      Performs the specified operation of the garbage collector.
    description: |
      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).
    parameters:
      - name: operation
        type: string
        default:
        summary: |
          The name of the operation that should be performed by the garbage
          collector.
    returns:
      - type: Variant
        summary: ''
    tags:
    code_samples:
  - name: error
    summary: |
      Halts thread execution and throws an error.
    description: |
      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 such as `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.
    parameters:
      - name: message
        type: string
        default:
        summary: |
          The error message to display.
      - name: level
        type: int
        default: 1
        summary: |
          The level of information that should be printed. Defaults to 1.
    returns:
      - type: void
        summary: ''
    tags:
    code_samples:
  - name: getfenv
    summary: |
      Returns the current environment in use by the caller, as a dictionary.
    description: |
      Returns the current environment in use by the caller, as a dictionary.

      - If provided with a function, the environment of the function will be
        returned.
      - If provided with an integer, `Global.LuaGlobals.getfenv()` will provide
        the environment of the function at the provided stack level: Level 1 is
        the function calling `Global.LuaGlobals.getfenv()`. If `stack` is `0`,
        `Global.LuaGlobals.getfenv()` returns the global environment of the
        current script. When using `Global.LuaGlobals.getfenv()` to get the
        current environment of a script, it will return the same table every
        time within the specific thread.
    parameters:
      - name: stack
        type: Variant
        default: 1
        summary: |
          The stack level (int) of the environment to be returned; or the
          function whose environment will be returned.
    returns:
      - type: table
        summary: ''
    tags:
      - Deprecated
    deprecation_message: |
      This function allows uncontrolled change of the global/function
      environment and disables script optimizations. Changes to the environment
      are not tracked by the script analysis tooling and may result in missing
      or incorrect warnings. As a replacement, consider using
      `Library.debug.info()` instead.
    code_samples:
  - name: getmetatable
    summary: |
      Returns the metatable of the given table.
    description: |
      Returns the metatable of the given table `t` if it has one, otherwise
      returns nil. If `t` does have a metatable, and the `__metatable`
      metamethod is set, it returns that value instead.

      ```lua
      -- Demonstrate getmetatable:
      local meta = {}
      local t = setmetatable({}, meta)
      print(getmetatable(t) == meta) --> true
      -- Make the original metatable unrecoverable by setting the __metatable metamethod:
      meta.__metatable = "protected"
      print(getmetatable(t)) --> protected
      ```
    parameters:
      - name: t
        type: Variant
        default:
        summary: |
          The object to fetch the metatable of.
    returns:
      - type: Variant
        summary: ''
    tags:
    code_samples:
  - name: ipairs
    summary: |
      Returns an iterator function and the table for use in a for loop.
    description: |
      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:

      ```lua
      local fruits = {"apples", "oranges", "kiwi"}
      for index, fruit in ipairs(fruits) do
         print(index, fruit) --> 1 apples, 2 oranges, 3 kiwi, etc...
      end
      ```
    parameters:
      - name: t
        type: Array
        default:
        summary: |
          A table whose elements are to be iterated over.
    returns:
      - type: function
        summary: ''
      - type: Array
        summary: ''
      - type: int
        summary: ''
    tags:
    code_samples:
  - name: loadstring
    summary: |
      Returns the provided code as a function that can be executed.
    description: |
      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()`.

      `loadstring()` is disabled by default. For guidance around enabling it,
      see `Class.ServerScriptService`.
    parameters:
      - name: contents
        type: string
        default:
        summary: |
          The specified string to be loaded as Lua code.
      - name: chunkname
        type: string
        default:
        summary: |
          An optional chunk name for error messages and debug information. If
          unspecified, Lua uses the `contents` string.
    returns:
      - type: Variant
        summary: ''
    tags:
    code_samples:
  - name: newproxy
    summary: |
      Creates a blank `userdata`, with the option for it to have a metatable.
    description: |
      Creates a blank `userdata`, with the option for it to have a metatable.
    parameters:
      - name: addMetatable
        type: bool
        default: false
        summary: ''
    returns:
      - type: userdata
        summary: ''
    tags:
    code_samples:
  - name: next
    summary: |
      An iterator function for use in for loops.
    description: |
      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 `ipairs`.

      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.
    parameters:
      - name: t
        type: table
        default:
        summary: |
          The array to be traversed.
      - name: lastKey
        type: Variant
        default: nil
        summary: |
          The last key that was previously retrieved from a call to next.
    returns:
      - type: Variant
        summary: ''
      - type: Variant
        summary: ''
    tags:
    code_samples:
  - name: pairs
    summary: |
      Returns an iterator function and the provided table for use in a `for`
      loop.
    description: |
      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:

      ```lua
      local scores = {
          ["John"] = 5,
          ["Sally"] = 10
      }

      for name, score in pairs(scores) do
          print(name .. " has score: " .. score)
      end
      ```
    parameters:
      - name: t
        type: table
        default:
        summary: |
          An array or dictionary table to iterate over.
    returns:
      - type: function
        summary: ''
      - type: table
        summary: ''
    tags:
    code_samples:
  - name: pcall
    summary: |
      Runs the provided function and catches any error it throws, returning the
      function's success and its results.
    description: |
      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.
    parameters:
      - name: func
        type: function
        default:
        summary: |
          The function to be called in protected mode.
      - name: args
        type: Tuple
        default:
        summary: |
          The arguments to send to `func` when executing.
    returns:
      - type: bool
        summary: ''
      - type: Variant
        summary: ''
    tags:
    code_samples:
  - name: print
    summary: |
      Prints all provided values to the output.
    description: |
      Receives any number of arguments, and prints their values to the output.
      `print` is not intended for formatted output, but only as a quick way to
      show a value, typically for debugging. For a formatted output, use
      `Library.string.format()`. On Roblox, `print` does not call `tostring`,
      but the `__tostring` metamethod still fires if the table has one.
    parameters:
      - name: params
        type: Tuple
        default:
        summary: |
          Any number of arguments to be outputted.
    returns:
      - type: void
        summary: ''
    tags:
    code_samples:
  - name: rawequal
    summary: |
      Returns whether `v1` is equal to `v2`, bypassing their metamethods.
    description: |
      Checks whether `v1` is equal to `v2`, without invoking any metamethods.
    parameters:
      - name: v1
        type: Variant
        default:
        summary: |
          The first variable to compare.
      - name: v2
        type: Variant
        default:
        summary: |
          The second variable to compare.
    returns:
      - type: bool
        summary: ''
    tags:
    code_samples:
  - name: rawget
    summary: |
      Gets the real value of `table[index]`, bypassing any metamethods.
    description: |
      Gets the real value of `table[index]`, without invoking any metamethods.
    parameters:
      - name: t
        type: table
        default:
        summary: |
          The table to be referenced.
      - name: index
        type: Variant
        default:
        summary: |
          The index to get from `t`.
    returns:
      - type: Variant
        summary: ''
    tags:
    code_samples:
  - name: rawlen
    summary: |
      Returns the length of the string or table, bypassing any metamethods.
    description: |
      Returns the length of the string or table, without invoking any
      metamethods.
    parameters:
      - name: t
        type: table
        default:
        summary: |
          The table to be referenced.
    returns:
      - type: table
        summary: ''
    tags:
    code_samples:
  - name: rawset
    summary: |
      Sets the real value of `table[index]`, bypassing any metamethods.
    description: |
      Sets the real value of `table[index]` to a given `value`, without invoking
      any metamethod.
    parameters:
      - name: t
        type: table
        default:
        summary: |
          The table to be referenced.
      - name: index
        type: Variant
        default:
        summary: |
          The index to set in `t` to a specified `value`. Must be different from
          nil.
      - name: value
        type: Variant
        default:
        summary: |
          The value to be set to a specified `index` in table `t`.
    returns:
      - type: table
        summary: ''
    tags:
    code_samples:
  - name: select
    summary: |
      Returns all arguments after the given index.
    description: |
      Returns all arguments after argument number `index`. If negative, it will
      return from the end of the argument list.

      ```lua
      print(select(2, "A", "B", "C")) --> B C
      print(select(-1, "A", "B", "C")) --> C
      ```

      Returns the total number of arguments that were passed after the `cmd`
      argument, which must be `"#"` to use `select` in this fashion.

      ```lua
      print(select("#", "A", "B", "C")) --> 3
      ```

      If `cmd` is a number, the function will return all values after that
      index.

      ```lua
      print(select(2, "A", "B", "C")) --> B C
      ```
    parameters:
      - name: index
        type: Variant
        default:
        summary: |
          The index of the argument to return all arguments after in `args`. or
          must be "#".
      - name: args
        type: Tuple
        default:
        summary: |
          A tuple of arguments.
    returns:
      - type: Tuple
        summary: ''
    tags:
    code_samples:
  - name: setfenv
    summary: |
      Sets the given function's environment.
    description: |
      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.

      If `f` is `0`, then `setfenv()` changes the environment of the running
      thread and returns no values.
    parameters:
      - name: f
        type: Variant
        default:
        summary: |
          Either a function or a number that specifies the function at that
          stack level.
      - name: fenv
        type: table
        default:
        summary: |
          The function environment table to set for the specified function.
    returns:
      - type: Variant
        summary: ''
    tags:
      - Deprecated
    deprecation_message: |
      This function allows uncontrolled change of the global/function
      environment and disables script optimizations. Changes to the environment
      are not tracked by the script analysis tooling and may result in missing
      or incorrect warnings.
    code_samples:
  - name: setmetatable
    summary: |
      Sets the given table's metatable.
    description: |
      Sets the metatable for the given table `t` to `newMeta`. If `newMeta` is
      nil, the metatable of `t` is removed. Finally, this function returns the
      table `t` which was passed to it. If `t` already has a metatable whose
      `__metatable` metamethod is set, calling this on `t` raises an error.

      ```lua
      local meta = {__metatable = "protected"}
      local t = {}
      setmetatable(t, meta) -- This sets the metatable of t
      -- We now have a table, t, with a metatable. If we try to change it...
      setmetatable(t, {}) --> Error: cannot change a protected metatable
      ```
    parameters:
      - name: t
        type: table
        default:
        summary: |
          The table to set the metatable of.
      - name: newMeta
        type: Variant
        default:
        summary: |
          If nil, the metatable of the given table `t` is removed. Otherwise,
          the metatable to set for the given table `t`.
    returns:
      - type: table
        summary: ''
    tags:
    code_samples:
  - name: tonumber
    summary: |
      Returns the provided value converted to a number, or nil if impossible.
    description: |
      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.

      ```lua
      print(tonumber("1337")) --> 1337 (assumes base 10, decimal)
      print(tonumber("1.25")) --> 1.25 (base 10 may have decimal portions)
      print(tonumber("3e2")) --> 300 (base 10 may have exponent portion, 3 × 10 ^ 2)
      print(tonumber("25", 8)) --> 21 (base 8, octal)
      print(tonumber("0x100")) --> 256 (assumes base 16, hexadecimal)
      print(tonumber("roblox")) --> nil (does not raise an error)
      -- Tip: use with assert if you would like unconvertable numbers to raise an error
      print(assert(tonumber("roblox"))) --> Error: assertion failed
      ```
    parameters:
      - name: arg
        type: Variant
        default:
        summary: |
          The object to be converted into a number.
      - name: base
        type: int
        default: 10
        summary: |
          The numerical base to convert `arg` into.
    returns:
      - type: Variant
        summary: ''
    tags:
    code_samples:
  - name: tostring
    summary: |
      Returns the provided value converted to a string, or nil if impossible.
    description: |
      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 `e` has a `__tostring` metamethod, then
      it will be called with `e` as the only argument and will return the
      result.

      ```lua
      local isRobloxCool = true
      -- Convert the boolean to a string then concatenate:
      print("Roblox is cool: " .. tostring(isRobloxCool)) --> Roblox is cool: true
      ```
    parameters:
      - name: e
        type: Variant
        default:
        summary: |
          The object to be converted into a string.
    returns:
      - type: string
        summary: ''
    tags:
    code_samples:
  - name: type
    summary: |
      Returns the basic type of the provided object.
    description: |
      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", "vector", "function", "thread",
      and "userdata".
    parameters:
      - name: v
        type: Variant
        default:
        summary: |
          The object to return the type of.
    returns:
      - type: string
        summary: ''
    tags:
    code_samples:
  - name: unpack
    summary: |
      Returns all elements from the given list as a tuple.
    description: |
      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.
    parameters:
      - name: list
        type: table
        default:
        summary: |
          The list of elements to be unpacked.
      - name: i
        type: int
        default: 1
        summary: |
          The index of the first element to unpack.
      - name: j
        type: int
        default: '#list'
        summary: |
          The index of the last element to unpack.
    returns:
      - type: Variant
        summary: ''
    tags:
    code_samples:
  - name: xpcall
    summary: |
      Similar to `pcall()` except it uses a custom error handler.
    description: |
      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`.
    parameters:
      - name: f
        type: function
        default:
        summary: |
          The function to be called in protected mode.
      - name: err
        type: function
        default:
        summary: |
          The function to be used as an error handle if xpcall catches an error.
      - name: args
        type: Tuple
        default:
        summary: ''
    returns:
      - type: bool
        summary: ''
      - type: Variant
        summary: ''
    tags:
    code_samples: