Courses/Lua/Introduction to Lua

Introduction to Lua

Discover why Lua powers game engines, embedded systems, and millions of scripts worldwide.

Our editor simulates Lua logic using JavaScript. For real Lua, download Lua or use an online interpreter like lua.org/demo.

What You'll Learn

What Lua is and where it's used in the real world
How to write and run your first Lua script
Lua's basic data types: nil, boolean, number, string
Variables, comments, and string concatenation

What Is Lua?

Lua (meaning "moon" in Portuguese) is a lightweight, high-performance scripting language designed to be embedded inside larger applications. Created in 1993 at the Pontifical Catholic University of Rio de Janeiro, it has become the most popular scripting language in the game industry.

🎮 Real-World Analogy: Think of Lua as a universal remote control. Just as a remote doesn't contain the TV itself but controls what happens on screen, Lua doesn't build entire applications — it scripts the behaviour of a host program like a game engine.

Where Lua Is Used

Roblox — All game logic is written in Luau (a Lua dialect)
World of Warcraft — UI addons and macros
LÖVE2D — A complete 2D game framework
Nginx / OpenResty — High-performance web scripting
Redis — Server-side scripting for database operations
Neovim — Plugin and configuration scripting

Hello, Lua!

See how Lua syntax works with your first program.

Try it Yourself »

JavaScript

// Your First Lua Program — simulated in JavaScript
console.log("=== Hello, Lua! ===");
console.log();

// In Lua you write:
// print("Hello, World!")

console.log("Lua Syntax:");
console.log('print("Hello, World!")');
console.log();
console.log("Output: Hello, World!");
console.log();

console.log("=== Why Lua? ===");
console.log("Created in 1993 at PUC-Rio, Brazil by Roberto Ierusalimschy.");
console.log();
const reasons = [
  "🎮 #1 scripting language for game engines (Roblox, LÖVE2D, WoW)",

...

Your First Script

A Lua script is simply a text file (usually .lua) containing instructions. Here is the simplest possible program:

print("Hello, World!")

That's it — no boilerplate, no imports, no main function. Lua starts executing from the first line of the file.

To run this, save the line above in a file called hello.lua and run lua hello.lua in your terminal.

Comments

-- This is a single-line comment

--[[
  This is a
  multi-line comment
]]

Variables and Data Types

Lua is dynamically typed, meaning you don't declare a variable's type — Lua figures it out from the value you assign.

local name = "Alice"    -- string
local age = 25           -- number (all numbers are 64-bit floats)
local active = true      -- boolean
local nothing = nil      -- nil means "no value"

print(type(name))        -- "string"
print(type(age))         -- "number"

The local keyword creates a variable scoped to the current block. Without it, the variable becomes global — which is generally bad practice.

⚠️ Common Mistake

Forgetting local creates a global variable that can be accidentally overwritten anywhere in your code. Always use local unless you have a specific reason not to.

String Concatenation

Lua uses .. (two dots) to join strings — not + like most other languages:

local greeting = "Hello, " .. name .. "!"
print(greeting)  -- Hello, Alice!

Variables & Types

Explore Lua's data types and type checking.