Basic lua: Introduction

What is Lua Script

Lua Script is a lightweight, cross-platform scripting language that was originally created as an extension of sorts, to further extend upon already existing programming languages, but over time, it has grown in popularity due to how easy it is to learn, & the amount of time saved in creating simple procedural scripts, functions & tables, thus Lua script is now the primary or secondary scripting language of multiple game engines. It is also used in various applications & web design.

For more information please see: here & here.

What is the meaning of LUA

Actually it's not LUA at all. Lua is not an abbreviation or acronym of any kind, it is simply the Portuguese word for moon.

What languages is Lua similar to

Lua, is similar to programming languages such as C, C#, C++, & Java to name a few, although Lua is relatively basic in comparison. The similarities are based on the structure of the languages & the way that they are written out - well for me anyway.

The basics

Print

The print function is used for printing messages to the log file or lua console & is useful for debugging your scripts & functions.

print("hello world") -- prints "hello world" into the log/console (ah yes how cliché of me, but it had to be done)

Concatenation

Concatenation is essentially the joining of two or more strings & is represented by two full stops like so ..

a = "hello"
b = "world"

print(a .. " " .. b) -- prints "hello world" - we had to add " " to create a space between the 2 words

Comments

Single line comments can be placed on their own line or at the end of a line.

-- this is a single line comment
i = 10 -- comment placed after working code
-- comment place before code; i = 10 -- notice how the code is also commented out?

Multi-line comments can be placed anywhere in the script & allow you to write comments over multiple lines.

--[[
this is a multiple line comment
I can go on & on & on
& on & on
& on.
]]

local i = 2 * --[[ this is a comment ]] 2
print(i) -- would print 4 to the log (2x2)

Nested multi-line comments allow you to comment out entire blocks of code, even if they already contain multi-line comments, thus preventing existing multi-line comments from ending the nested comment. Note: It seems that, nested comments are not included in the geshi lua syntax, as the comments should be completely grayed out, but I can assure that they work.

--[=[
this is a nested comment
see how --[[ we can include ]]
a multi-line comment inside of it?
]=]

--[[
this is what would happen if we were to use
a regular multi-line --[[ comment ]]
i = 10
]]