struct Str {
    pub u64: size
    pub &char: data
impl:

    inline fn Str.substr(u64: start u64: len Str: s) -> [Str] {
        len s::data start ptr+ cast(Str)
    } 

    fn Str.equals(Str: s1 Str:s2) -> [bool] {
        s1::size s2::size != if {
            false return
        }
        0 while dup s1::size < do {
            as [i]
            s1::data i ptr+ @ 
            s2::data i ptr+ @ != if {
                false return
            }
            i 1 + 
        } drop

        true
    }

    fn Str.starts_with(Str: s2 Str: s1) -> [bool] {
        s2::size s1::size > if {
            false return
        }

        0 s2::size s1 Str.substr
        s2 
        Str.equals 
    }

    fn Str.to_int(Str: mut s) -> [u64] {
        0
        while s::data @ char.is_digit do {
            10 * s::data @ '0' - +
            s::data 1 ptr+ *s::data !
        }
    }
}

impl Write<Str> {
    inline fn write(Str: s u64: fd) {
        s::size s::data fd sys_write drop
    }
}

impl ToString<Str> {
    inline fn to_string(Str) -> [String] { String.new } 
}

impl Format<Str> {
    inline fn fmt(String Str) -> [String] { String.push_str }
}