03_functions.nula

// 03_functions.nula - Functions, closures, and recursion
// Demonstrates: fn, let rec, multi-arg closures, blocks
//
// Run: nulang examples/03_functions.nula

// Simple closure
let greet = fn(name) {
    "Hello, " + name + "!"
}
perform IO.print(greet("Alice"))

// Multi-argument closure
let add = fn(x, y) { x + y }
let multiply = fn(x, y) { x * y }

let sum = add(40, 2)
let product = multiply(6, 7)
perform IO.print("40 + 2 = " + perform Int.to_string(sum))
perform IO.print("6 * 7 = " + perform Int.to_string(product))

// Block expression returning a value
let result = {
    let a = 10
    let b = 20
    a + b
}
perform IO.print("Block result: " + perform Int.to_string(result))

// Recursive closure with let rec
let rec factorial = fn(n) {
    if n <= 1 then 1 else n * factorial(n - 1)
}
perform IO.print("5! = " + perform Int.to_string(factorial(5)))
perform IO.print("10! = " + perform Int.to_string(factorial(10)))

// Recursive Fibonacci
let rec fib = fn(n) {
    if n <= 1 then n else fib(n - 1) + fib(n - 2)
}
perform IO.print("fib(10) = " + perform Int.to_string(fib(10)))