range.zig

const std = @import("std");
const assert = std.debug.assert;
const warn = std.debug.warn;

fn abs(comptime x: comptime_int) comptime_int {
    return if (x < 0) -x else x;
}

pub fn range(comptime inclusive: bool, comptime a: comptime_int, comptime b: comptime_int, comptime step: comptime_int) [@divTrunc(abs(b - a), step) + if (inclusive) 1 else 0](if (a < 0) isize else usize) {
    comptime assert(a < b);
    comptime assert(a + step <= b);

    comptime var res: [@divTrunc(abs(b - a), step) + if (inclusive) 1 else 0](if (a < 0) isize else usize) = undefined;
    comptime var idx = 0;
    while (idx < res.len) {
        res[idx] = a + step * idx;
        idx += 1;
    }

    return res;
}

test "static ranges" {
    warn("\n");
    for (comptime range(false, 10000, 60000, 10000)) |val| {
        warn("{}, ", val);
    }
    warn("\n");
    for (comptime range(false, -1, 7, 2)) |val| {
        warn("{}, ", val);
    }
    warn("\n");
    for (comptime range(false, -120, 77, 80)) |val| {
        warn("{}, ", val);
    }
    warn("\n");
    for (comptime range(false, -9, 13, 1)) |val| {
        warn("{}, ", val);
    }
}