fn bump(bytes: MutSpan<u8>) -> String {
    bytes[0] = bytes[0] + 1_u8
    return bytes[..1]
}

fn firstByte(text: String) -> u8 {
    return text[0]
}

pub fn main(world: World) -> Void raises {
    var storage: [1]u8 = [96]
    var ok: Bool = true
    if !std.mem.eql(bump(storage), "a") {
        ok = false
    }
    if storage[0] != 97_u8 {
        ok = false
    }
    if firstByte(bump(storage)) != 98_u8 {
        ok = false
    }
    if storage[0] != 98_u8 {
        ok = false
    }
    if !std.mem.eql(bump(storage), "c") {
        ok = false
    }
    if storage[0] != 99_u8 {
        ok = false
    }
    if ok {
        check world.out.write("byte view call single eval ok\n")
    }
}