type Window {
    bytes: Span<u8>,
}

fn middle(bytes: Span<u8>) -> Span<u8> {
    return bytes[1..3]
}

fn spanWindow(bytes: Span<u8>) -> Span<u8> {
    return bytes[1..4]
}

pub fn main(world: World) -> Void raises {
    let bytes: [5]u8 = [65, 66, 67, 68, 69]
    let start: usize = 1
    let end: usize = 4
    let arraySlice: Span<u8> = bytes[start..end]
    let span: Span<u8> = std.mem.span("ABCDE")
    let spanSlice: Span<u8> = span[1..4]
    let window: Window = Window { bytes: middle(span) }
    if std.mem.len(arraySlice) == 3 && arraySlice[0] == 66 && std.mem.len(spanSlice) == 3 && spanSlice[2] == 68 && std.mem.len(window.bytes) == 2 && window.bytes[1] == 67 && spanWindow(span)[2] == 68 {
        check world.out.write("range slices ok\n")
    }
}