use std

pkg libreadline =
    extern const Creadline: (prompt: byte# -> byte#)
    const readline: (prompt: byte[:] -> std.option(byte[:]))
    extern const Cadd_history: (line: byte# -> void)
    const add_history: (line: byte[:] -> void)
;;

const NULL = (0: byte#)

const readline = {prompt
    var ret = Creadline((std.fmt("{}\0", prompt): byte#))
    if ret == NULL
        -> `std.None
    else
        -> `std.Some std.cstrconvp(ret)
    ;;
}

const add_history = {line
    Cadd_history((std.fmt("{}\0", line): byte#))
}