(************************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2016     *)
(*   \VV/  **************************************************************)
(*    //   *      This file is distributed under the terms of the       *)
(*         *       GNU Lesser General Public License Version 2.1        *)
(************************************************************************)

(** Unicode utilities *)

type status = Letter | IdentPart | Symbol

exception Unsupported

(** Classify a unicode char into 3 classes, or raise [Unsupported] *)
val classify : int -> status

(** Check whether a given string be used as a legal identifier.
    - [None] means yes
    - [Some (b,s)] means no, with explanation [s] and severity [b] *)
val ident_refutation : string -> (bool * string) option

(** First char of a string, converted to lowercase *)
val lowercase_first_char : string -> string

(** Return [true] if all UTF-8 characters in the input string are just plain
    ASCII characters. Returns [false] otherwise. *)
val is_basic_ascii : string -> bool

(** [ascii_of_ident s] maps UTF-8 string to a string composed solely from ASCII
    characters. The non-ASCII characters are translated to ["_UUxxxx_"] where
    {i xxxx} is the Unicode index of the character in hexadecimal (from four
    to six hex digits). To avoid potential name clashes, any preexisting
    substring ["_UU"] is turned into ["_UUU"]. *)
val ascii_of_ident : string -> string

(** Validate an UTF-8 string *)
val is_utf8 : string -> bool