15_ranges.nula

// 15_ranges.nula - Range expressions and for-in-range loops
// Demonstrates: a .. b range syntax, for i in 0 .. N loops,
//               ranges with pipe operator, arithmetic with ranges
//
// Run: nulang examples/15_ranges.nula

perform IO.print("=== Range expressions ===")

// Basic for-in-range loop
perform IO.print("Count 0 to 4:")
for i in 0 .. 5 {
    perform IO.print("  " + perform Int.to_string(i))
}

// Sum over a range
let sum_range = fn(lo, hi) {
    let st = [0]
    for i in lo .. hi {
        st[0] = st[0] + i
    }
    st[0]
}
let s = sum_range(0, 10)
perform IO.print("Sum 0..10 = " + perform Int.to_string(s))

// Range with larger bounds
let big_sum = sum_range(1, 6)
perform IO.print("Sum 1..6 = " + perform Int.to_string(big_sum))

// For loop with range and break
let find_first_multiple = fn(lo, hi, m) {
    for i in lo .. hi {
        if i % m == 0 then break i else unit
    }
}
let first = find_first_multiple(5, 20, 7)
perform IO.print("First multiple of 7 in 5..20: " + perform Int.to_string(first))

// Nested range loops
perform IO.print("Small multiplication table:")
for a in 1 .. 4 {
    let st = [""]
    for b in 1 .. 4 {
        let prod = perform Int.to_string(a * b)
        if b == 1 then { st[0] = prod }
        else { st[0] = st[0] + " " + prod }
    }
    perform IO.print("  " + st[0])
}

// Range with arithmetic (precedence: arithmetic binds tighter than ..)
let squares = fn(n) {
    let st = [0]
    for i in 0 .. n {
        st[0] = st[0] + i * i
    }
    st[0]
}
perform IO.print("Sum of squares 0..5 = " + perform Int.to_string(squares(5)))

// Pipe through a range
let count_up = fn(n) {
    let st = [0]
    for i in 0 .. n {
        st[0] = st[0] + 1
    }
    st[0]
}
let counted = count_up(7)
perform IO.print("Counted 7 = " + perform Int.to_string(counted))

perform IO.print("Range demo complete!")