 local UserInputService = game:GetService("UserInputService")
local character = script.Parent

local humanoid = character:WaitForChild("Humanoid")
local doubleJumpEnabled = false
--function that checks what the character is doing: Jumping or Falling, then allows or denies the jump
function CheckState(oldState, newState)
	if newState == Enum.HumanoidStateType.Jumping then
		--if it is jumping and did not do the double jump, then
		if not doubleJumpEnabled then
			wait(.2)
			if humanoid:GetState() == Enum.HumanoidStateType.Freefall then
				doubleJumpEnabled = true
			end
		end
		--else, if the player has landed, then we can do the double jump again
	elseif newState == Enum.HumanoidStateType.Landed then
		doubleJumpEnabled = false
	end
end
--function that checks if the Space bar is pressed and organizes a double jump.
function GetJump(inputObject)
	if inputObject.KeyCode == Enum.KeyCode.Space then
		if doubleJumpEnabled then
			--if the humanoid is not in the jump state, then we change its state to jump
			if humanoid:GetState() ~= Enum.HumanoidStateType.Jumping then
				humanoid:ChangeState(Enum.HumanoidStateType.Jumping)
				spawn(function()
					doubleJumpEnabled = false
				end)
			end
		end
	end
end
humanoid.StateChanged:Connect(CheckState)
UserInputService.InputBegan:Connect(GetJump)

created 3 years ago

Lua online compiler

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name = io.read("*a")
print ("Hello ", name)

About Lua

Lua is a light weight embeddable scripting language which is built on top of C. It is used in almost all kind of applications like games, web applications, mobile applications, image processing etc. It's a very powerful, fast, easy to learn, open-source scripting language.

Syntax help

Variables

By default all the variables declared are global variables
If the variables are explicitly mentioned as local then they are local variables.
Lua is a dynamically typed language and hence only the values will have types not the variables.

Examples

-- global variables
a = 10

-- local variables

local x = 30

Value Type	Description
number	Represents numbers
string	Represents text
nil	Differentiates values whether it has data or not
boolean	Value can be either true or false
function	Represents a sub-routine
userdata	Represents arbitary C data
thread	Represents independent threads of execution.
table	Can hold any value except nil

Loops

1. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition)
do
--code
end

2. Repeat-Until:

Repeat-Until is also used to iterate a set of statements based on a condition. It is very similar to Do-While, it is mostly used when you need to execute the statements atleast once.

repeat
   --code
until( condition )

3. For:

For loop is used to iterate a set of statements based on a condition.

for init,max/min value, increment
do
   --code
end

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increase re-usuability and modularity.

optional_function_scope function function_name( argument1, argument2, argument3........, argumentn)
--code
return params with comma seperated
end