Loops and ranges

for i, v in 10..13 {            // the pass number, from 0, and the value
for n < 100 {                   // while `n < 100`
for {                           // until `break`

// Loops: `for` is the only loop. It goes over a range, an array or a slice,
// runs while a condition holds, or runs until `break`. `continue` goes on
// to the next pass.
// Run: peeper run examples/06_loops.peep
fn main() {
    print("range:");
    for i in 0..5 {
        print("", i);
    }
    println();

    print("numbered:");
    for i, v in 10..13 {            // the pass number, from 0, and the value
        print("", i, v);
    }
    println();

    let mut passes = 0;
    for 0..3 {                      // no name for the value
        passes = passes + 1;
    }
    println("passes:", passes);

    let mut n = 1;
    for n < 100 {                   // while `n < 100`
        n = n * 3;
    }
    println("while:", n);

    let mut x = 0;
    for {                           // until `break`
        x = x + 1;
        if x == 4 {
            break;
        }
    }
    println("forever:", x);

    print("odd:");
    for v in 0..10 {
        if v % 2 == 0 {
            continue;
        }
        if v > 7 {
            break;
        }
        print("", v);
    }
    println();
}

range: 0 1 2 3 4
numbered: 0 10 1 11 2 12
passes: 3
while: 243
forever: 4
odd: 1 3 5 7

fn evens(below: i32) -> range[i32] {
    return 0..below:2;
}

// Ranges: `a..b` counts from `a` up to `b`, `a..=b` takes `b` too, and
// `:step` steps by more than 1. A range counts down when `a > b`, and never
// wraps past its type's end. A range is a value of type `range[T]`: it is
// kept, passed, returned and copied like a number.
// Run: peeper run examples/07_ranges.peep
struct Window { values: range[u8], tag: i32 }

fn evens(below: i32) -> range[i32] {
    return 0..below:2;
}

fn total(values: range[i32]) -> i32 {
    let mut sum = 0;
    for v in values {
        sum = sum + v;
    }
    return sum;
}

fn main() {
    print("up:");
    for v in 0..5 { print("", v); }
    println();
    print("inclusive:");
    for v in 0..=5 { print("", v); }
    println();
    print("step:");
    for v in 0..10:3 { print("", v); }
    println();
    print("down:");
    for v in 5..=0:2 { print("", v); }
    println();
    print("top of u8:");
    for v in 250u8..=255 { print("", v); }
    println();

    let r = 1..=4;
    let copy = r;
    println("totals:", total(r), total(copy), total(evens(9)));

    let window = Window.{ values = 10..=20:5, tag = 1 };
    print("field:");
    for v in window.values { print("", v); }
    println(" tag", window.tag);

    println("spread:", [5]i32{(0..4)..., 100});   // a range's values in an array
}

up: 0 1 2 3 4
inclusive: 0 1 2 3 4 5
step: 0 3 6 9
down: 5 3 1
top of u8: 250 251 252 253 254 255
totals: 10 10 20
field: 10 15 20 tag 1
spread: [0, 1, 2, 3, 100]