Cheat Sheet

<cat>Dev.Lua</cat>
<title>Cheat Sheet</title>

# Lua Cheat Sheet

## Comments

```lua
-- This is a single line comment.  The Lua compiler will ignore this line completely.

--[[
	This is a multi-line comment.
	Anything between these pairs of square brackets will be ignored by the compiler.
]]

--[[ You can also use multi-line comments for in-line comments, if you want ]]

----

// Garry's Mod Lua supports using C-style comments, but they are not available in other forms of Lua and will appear as errors in many editors.

/*
	This is a C-style multi-line comment.
*/
```

## Variables

```lua
-- Local variables
local myVariable = 5 -- A local variable holding a number.
myVariable = 10 	 -- Variables can be re-used to hold a different value
myVariable = "Hi!" 	 -- Variables can even be re-used to hold a different type of data. (This can make your code confusing!)

-- Global variables
MY_VARIABLE = 2.15 	 -- Global variables are just like local variables but they're accessible from everywhere, even other addons!
```

## Data Types

```lua
--[[ Nil ]]--
-- Nil is a placeholder value representing a lack of data much in the same way that the number 0 represents a lack of quantity
nil

--[[ Strings ]]--
"I'm a string!"
'I\'m also a string!' -- Note that we use the escape character "\" in "I'm" to avoid ending the string prematurely

-- You can join (Or "Concatenate") strings together with ".." to make them into a single string
"Hello" .. " " .. "World!" -- This will create the string "Hello World!"

--[[ Numbers ]]--
15
0.56
8.3e10 -- This is the same as (8.3 * 10^10) or 83000000000
8.3e+10 -- This is the same as 8.3e10 but you can specify that it has an exponent of positive 10 if you want
8.3e-10 -- This is the same as 0.00000000083

--[[ Booleans ]]--
true 
false

--[[ Functions ]]--
-- A global function
function YellMessage( message )
	local loudMessage = string.upper( message ) .. "!"
	print( loudMessage )
end

-- A local function
local function AddNumbers( a, b )
	return a + b
end

-- Functions are just a data type like any other
local SubtractNumbers = function( a, b )
	return a - b
end

-- functions can return multiple values
local function SquareAndCube( a )
	return a^2, a^3
end

--[[ Tables ]]--
local myTable = {} -- An empty table

-- Tables can store data sequentially using automatically-assigned numerical keys starting from 1 (Called an "Index" or "Indices")
myTable = {
	100, 	-- This is index 1
	5, 		-- This is index 2
	200,	-- This is index 3
}

-- Table keys and values can be any data type
myTable = {
	["My Key"] = "My Value!", 	-- A string key and a string value
	[2] = true,					-- A number key and a boolean value
	[false] = function() 		-- A boolean key and a function value 
		print( "Howdy!" )
	end,
	[function()					-- A function key and a boolean value 
		print( "Hello!" )
	end] = true
}

-- Table keys and values can be changed, added, and removed at any time
myTable[ "My Key" ] = "A new value"

```

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