Lua is a lightweight, embeddable scripting language widely used in game engines (Defold, Roblox, Corona), configuration systems, automation tools, and embedded platforms.
This article gives you a clean, beginner-friendly introduction with complete and runnable examples.
1. Setting Up and Running Lua
Install Lua
- macOS
brew install lua
- Linux (Ubuntu/Debian)
sudo apt-get install lua5.4
- Windows
Download binaries or use Lua for Windows.
Run a Script
Write hello.lua:
print("Hello, Lua!")
Run:
lua hello.lua
Enter interactive REPL:
lua
> print("Hello REPL")
2. Basic Syntax and Data Types
Comments
-- single-line comment
--[[
multi-line
comment
]]
Variables
x = 10 -- global
local y = 20 -- local
print(x, y)
Core Types
nilbooleannumberstringtable(Lua’s all-purpose structure)function
Numbers & Operators
local a, b = 10, 3
print(a + b)
print(a - b)
print(a * b)
print(a / b)
print(a % b)
print(a ^ b) -- exponent
Strings
local s1 = "Hello"
local s2 = 'Lua'
local s3 = [[
Multi-line
string
]]
print(s1 .. ", " .. s2 .. "!") -- concatenation
print(#s1) -- length
3. Tables: Arrays, Dictionaries, Objects
Tables are the heart of Lua.
Arrays
local arr = {10, 20, 30}
print(arr[1])
print(arr[2])
print(arr[3])
Dictionaries
local person = {
name = "Alice",
age = 25
}
print(person.name)
print(person["age"])
Mixed Usage
local t = {
100, 200,
name = "Bob",
score = 95
}
print(t[1], t.name, t.score)
4. Control Flow
if / elseif / else
local score = 88
if score >= 90 then
print("A")
elseif score >= 80 then
print("B")
else
print("C or below")
end
while
local i = 1
while i <= 3 do
print(i)
i = i + 1
end
repeat … until
local n = 1
repeat
print(n)
n = n + 1
until n > 3
for numeric loop
for i = 1, 5 do
print(i)
end
for generic loop
Iterate array
local arr = {"Lua", "Python", "Go"}
for i, v in ipairs(arr) do
print(i, v)
end
Iterate dictionary
local config = {host="127.0.0.1", port=8080}
for k, v in pairs(config) do
print(k, v)
end
5. Functions
Basic Function
local function add(a, b)
return a + b
end
print(add(3, 5))
Multiple Return Values
local function divide(a, b)
if b == 0 then
return nil, "division by zero"
end
return a / b, nil
end
local v, err = divide(10, 0)
print(v, err)
Anonymous Function
local result = (function(x, y)
return x * y
end)(3, 4)
print(result)
6. Modules
Create math_utils.lua:
local M = {}
function M.add(a, b)
return a + b
end
function M.sub(a, b)
return a - b
end
return M
Use it:
local m = require("math_utils")
print(m.add(1, 2))
print(m.sub(5, 3))
7. Simple Object-Oriented Style
Lua uses tables + metatables to simulate objects.
local Person = {}
Person.__index = Person
function Person:new(name, age)
local obj = {name=name, age=age}
setmetatable(obj, self)
return obj
end
function Person:say()
print("Hi, I'm " .. self.name)
end
local p = Person:new("Alice", 25)
p:say()
8. Useful Standard Libraries
String
local s = "hello lua"
print(string.upper(s))
print(string.sub(s, 1, 5))
Math
math.randomseed(os.time())
print(math.random(1, 10))
Table
local t = {}
table.insert(t, "Lua")
table.insert(t, "is fun")
print(table.concat(t, " "))
9. Mini Example: Simple CLI Todo Tool
Save as todo.lua:
local todos = {}
local function add(text)
table.insert(todos, text)
print("Added:", text)
end
local function list()
if #todos == 0 then
print("No todos.")
return
end
for i, v in ipairs(todos) do
print(i .. ". " .. v)
end
end
print("Lua Todo CLI")
while true do
io.write("> ")
local line = io.read("*l")
if line == "quit" then break end
if line == "list" then
list()
elseif line:sub(1,3) == "add" then
add(line:sub(5))
else
print("Commands: add <text>, list, quit")
end
end
Run:
lua todo.lua
10. Next Steps
After mastering this introduction, continue with:
- Metatables & metamethods (
__index,__add, etc.) - Coroutines
- LuaRocks package manager
- Using Lua in engines (Defold, LÖVE)
Keep Reading
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