type t = string
exception Malformed_code
val validate : t -> unit
val get : t -> int -> UChar.uchar
val init : int -> (int -> UChar.uchar) -> t
val length : t -> int
type index = int
val nth : t -> int -> index
val last : t -> index
val look : t -> index -> UChar.uchar
val out_of_range : t -> index -> bool
val compare_index : t -> index -> index -> int
val next : t -> index -> index
val prev : t -> index -> index
val move : t -> index -> int -> index
val iter : (UChar.uchar -> unit) -> t -> unit
val compare : t -> t -> int
module Buf :
  sig
    type buf = UTF8.Buf.buf
    val create : int -> buf
    val contents : buf -> t
    val clear : buf -> unit
    val reset : buf -> unit
    val add_char : buf -> UChar.uchar -> unit
    val add_string : buf -> t -> unit
    val add_buffer : buf -> buf -> unit
  end