declare comptime fn echo(...args: any[])

declare comptime fn print(...arg: any[])

declare comptime fn printf(...arg: any[])

declare comptime fn println(...arg: any[])

declare comptime fn scan(msg: str?) -> str

trait Reader {
    read() throws -> (buf: str, n: num)
}

trait Writer {
    write(buf: str) throws -> num
}

trait Closer {
    close() throws
}

trait Seeker {
    seek(offset: num) throws -> num 
}

declare comptime fn copy(dst: Writer, src: Reader) throws -> num

declare comptime fn read_all(r: Reader) throws -> str

declare comptime fn write_string(w: Writer, str: str) throws -> num