1 – Introduction

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.

Lua is free software, and is provided as usual with no guarantees, as stated in its copyright notice. The implementation described in this manual is available at Lua’s official web site, www.lua.org.

Lua means “moon” in Portuguese and is pronounced LOO-ah.