1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
-- Single line comment
--[[
Multi-line comment
supports multiple lines
]]

-- Print statement
print("Hello, World!")

-- Basic variable declaration
local x = 10
global_var = 20  -- Global variable (avoid when possible)

-- Function definition
function greet(name)
    return "Hello, " .. name .. "!"
end

-- Calling a function
print(greet("Lua Developer"))

1
2
3
4
5
6
7
8
9
10
11
12
13
14
-- Primitive Types
local nil_var = nil         -- Represents absence of a value
local bool_true = true      -- Boolean true
local bool_false = false    -- Boolean false
local num_int = 42          -- Integer
local num_float = 3.14      -- Floating-point number
local str_simple = "Lua"    -- String

-- Complex Types
local table_array = {1, 2, 3}                 -- Array-like table
local table_dict = {name = "Lua", version = 5.4}  -- Dictionary-like table
local function_var = function() end            -- Function as first-class value
local thread_var = coroutine.create(function() end)  -- Coroutine thread

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
-- Local variables (recommended)
local x = 10
local y = 20

-- Global variables (use sparingly)
global_value = 30

-- Multiple variable assignment
local a, b, c = 1, 2, 3

-- Constants (use convention, no true constants)
local PI = 3.14159
local MAX_CONNECTIONS = 100

-- Scope demonstration
local function scope_demo()
    local local_var = "I'm local"  -- Function-level local
    internal_var = "I'm global"    -- Becomes global
end

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
-- Arithmetic
local sum = 5 + 3       -- Addition
local diff = 10 - 4     -- Subtraction
local prod = 3 * 6      -- Multiplication
local div = 15 / 3      -- Division
local mod = 10 % 3      -- Modulo
local pow = 2 ^ 3       -- Exponentiation

-- Comparison
local is_equal = (5 == 5)       -- Equality
local is_not_equal = (5 ~= 6)   -- Inequality
local greater = (10 > 5)        -- Greater than
local less_or_equal = (3 <= 4)  -- Less than or equal

-- Logical
local and_op = true and false   -- Logical AND
local or_op = true or false     -- Logical OR
local not_op = not true          -- Logical NOT

-- String Concatenation
local full_name = "Lua" .. " " .. "Programming"

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
-- If-Else
local age = 20
if age < 18 then
    print("Minor")
elseif age >= 18 and age < 65 then
    print("Adult")
else
    print("Senior")
end

-- For Loops
-- Numeric loop
for i = 1, 5 do
    print(i)  -- Prints 1, 2, 3, 4, 5
end

-- Reverse loop
for i = 5, 1, -1 do
    print(i)  -- Prints 5, 4, 3, 2, 1
end

-- Generic loop (iterate over tables)
local fruits = {"apple", "banana", "cherry"}
for index, fruit in ipairs(fruits) do
    print(index, fruit)
end

-- While Loop
local count = 0
while count < 5 do
    print(count)
    count = count + 1
end

-- Repeat-Until Loop
local x = 0
repeat
    x = x + 1
    print(x)
until x >= 5

-- Break and Continue
for i = 1, 10 do
    if i == 3 then
        break  -- Exit loop
    end
    print(i)
end

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
-- Simple function
function add(a, b)
    return a + b
end

-- Function with multiple return values
function get_person_details()
    return "John", 30, "Engineer"
end

-- Anonymous/Lambda functions
local multiply = function(a, b) return a * b end

-- Closures
function counter()
    local count = 0
    return function()
        count = count + 1
        return count
    end
end
local increment = counter()
print(increment())  -- 1
print(increment())  -- 2

-- Variadic functions
function sum(...)
    local total = 0
    for _, v in ipairs({...}) do
        total = total + v
    end
    return total
end
print(sum(1, 2, 3, 4))  -- 10

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
-- Tables as Arrays
local fruits = {"apple", "banana", "cherry"}
print(fruits[1])  -- "apple" (1-based indexing)
table.insert(fruits, "date")
table.remove(fruits, 2)

-- Tables as Dictionaries
local person = {
    name = "John",
    age = 30,
    city = "New York"
}
print(person.name)
person.job = "Developer"

-- Mixed Tables
local mixed = {
    42,
    name = "Mixed Table",
    [true] = "Boolean key"
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
-- Metatable-based OOP
local Person = {}
Person.__index = Person

function Person.new(name, age)
    local self = setmetatable({}, Person)
    self.name = name
    self.age = age
    return self
end

function Person:introduce()
    print("Hi, I'm " .. self.name)
end

local john = Person.new("John", 30)
john:introduce()

-- Inheritance
local Student = setmetatable({}, {__index = Person})
function Student.new(name, age, grade)
    local self = Person.new(name, age)
    setmetatable(self, Student)
    self.grade = grade
    return self
end

function Student:study()
    print(self.name .. " is studying")
end

local jane = Student.new("Jane", 25, 12)
jane:introduce()  -- Inherited method
jane:study()      -- Student's method

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
-- Protected Call
local function divide(a, b)
    if b == 0 then
        error("Cannot divide by zero")
    end
    return a / b
end

local status, result = pcall(divide, 10, 2)
print(status, result)  -- true, 5

local status, err = pcall(divide, 10, 0)
print(status, err)     -- false, error message

-- Custom Error Handling
local function custom_error_handler(err)
    print("Custom error handler: " .. err)
    return err
end

xpcall(function()
    error("Something went wrong")
end, custom_error_handler)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
-- Writing to a file
local file = io.open("example.txt", "w")
file:write("Hello, Lua!")
file:close()

-- Reading from a file
local file = io.open("example.txt", "r")
local content = file:read("*all")
print(content)
file:close()

-- Iterating through file lines
for line in io.lines("example.txt") do
    print(line)
end

1
2
3
4
5
6
7
8
9
10
11
12
13
-- Using LuaUnit
local lu = require("luaunit")

function test_addition()
    lu.assertEquals(1 + 1, 2)
end

function test_string_concat()
    lu.assertEquals("Hello" .. " World", "Hello World")
end

os.exit(lu.LuaUnit.run())