Links

• See also:  MoonScript, a language that compiles to Lua
• Libraries
• Live web-based interpreter
• pdf: Programming with Multiple Paradigms in Lua
• Faq
• Unofficial FAQ
• Gotchas
• A nice set of docs
  • Beware: Only use the links that start with "Lua".
• Lua Tricks (introductory material)
• Loops and Control Structures
• Named arguments (like keyword parameters)
• Lua Functional Programming
  • Inspired by and based on Paul Graham's work On Lisp
  • Introduction
  • Functions
• Online book: Programming in Lua
  • This is an online version of the first edition of the book
  • Part II · Tables and Objects
    • Data Structures
      • Sets and Bags
      • String Buffers
    • Serialization
    • Metatables and Metamethods
    • Accessing Global Variables with Dynamic Names
    • Packages
    • Object-Oriented Programming
    • Weak Tables
      • Memoize Functions
      • Object Attributes
      • Revisiting Tables with Default Values
  • Part III · The Standard Libraries
    • The Mathematical Library
    • The Table Library
    • The String Library
      • Tricks of the Trade
    • The I/O Library
    • The Operating System Library
    • The Debug Library
      • Introspective Facilities
      • Hooks
      • Profiles
• Wiki are not easy to find from there.
  • Sample Code
    • Split Join
    • String Recipes
    • Range Iterator
  • Expressions Tutorial
• Manual - Table of Contents
  • single page
  • Coroutines
  • Modules
  • Basic Functions
  • Values and Types
  • Variables
  • Statements
    • Chunks
    • Blocks
    • Assignment
    • Control Structures
    • Function Calls as Statements
    • Local Declarations
  • Expressions
    • Arithmetic Operators
    • Relational Operators
    • Logical Operators
    • Concatenation
    • The Length Operator
    • Precedence
    • Table Constructors
    • Function Calls
    • Function Definitions
• LUA 5.2
  • Welcome to Lua 5.2
  • What Lua 5.1 code breaks in Lua 5.2?
  • Incompatibilities with the Previous Version
  • luajit 2.x: Supported 5.2 Extensions
• Memoization
  • Func Tables: Memoization

Types

There are eight basic types in Lua: nil, boolean, number, string, function, userdata, thread, and table. Nil is the type of the value nil

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 can 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 can contain functions. Thus tables can 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.