Lua Language

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Introduction

Lua is a lightweight, scripting programming language based on an interpreter generating compiled bytecodes.

It was designed in Brasil by Roberto Ierusalimschy, Waldemar Celes and Luiz Henrique de Figueiredo in 1993.

CE Lua is a specific version of Lua interpreter adapted by Dark Byte for Cheat Engine.

Syntax

CE Lua interpreter respects traditional LUA syntax and provides some extra features. The Lua Script Editor provide a real-time colored syntax and a Syntax Check feature (Ctrl+Alt+C).

Comments

In Lua simple comments begin with -- and end at the end of line. Multi-line comments begin with --[[ and end with ]] .

-- This is a simple comment just to the end of this line
This is not a comment but a future syntax error -- This is a new simple comment
--[[ First line of a multi-line comment
Second line of a multi-line comment
Last line of a multi-line comment]]

Variables

In Lua variables are polymorphic (can change the type during theirs lifes). By default a variable is global unless the declaration begins with local modifier.

Any variable can host:

  • nothing (not defined, equal to nil)
  • a numerical value (no difference between integer or float values, nor between different precisions)
  • a boolean value (true/false)
  • a string
  • a table
  • a function

Warning: the basic arithmetic operators like + or - are defined only for numericals.

Examples:

MyVar1 = nil           -- global variable MyVar1 having nothing inside (no type neither)
MyVar2 = UnknownVar    -- another global variable equal to nil (because UnknowVar is not yet defined)
local MyVar3 = 2       -- local numerical variable MyVar3 equal to 2
MyVar4 = 'Hello'       -- global string variable MyVar4
local MyVar5 = "Hello" -- local string variable MyVar5 having the same string as MyVar3
MyVar6 = [[First Line
Second Line.]]         -- global multi-line string variable MyVar6 beginning with 'First' and ending with 'Line.'
MyVar2 = (10 > 7.55)   -- now MyVar2 becomes a boolean equal to true

Flow control

Lua provides a conditional test with mutiple, optional branches:

if BooleanExpression then
  -- if statement(s) body
elseif BooleanExpression then  -- optional
  -- elseif statement(s) body
else                           -- optional
  -- else/default statement(s) body
end

and several conditional loops:

while BooleanExpression do    -- do statements while BooleanExpression is true
  --statements
end

repeat                        -- repeat statements
  --statements
until BooleanExpression       -- until BooleanExpression is true

for i = start, stop, step do  -- any numerical value for start, stop and step
  --statements
end                           -- until i value equals stop value


Functions

Tables

External links