(**************************************************************************)
(*                                                                        *)
(*  The Why platform for program certification                            *)
(*                                                                        *)
(*  Copyright (C) 2002-2014                                               *)
(*                                                                        *)
(*    Jean-Christophe FILLIATRE, CNRS & Univ. Paris-sud                   *)
(*    Claude MARCHE, INRIA & Univ. Paris-sud                              *)
(*    Yannick MOY, Univ. Paris-sud                                        *)
(*    Romain BARDOU, Univ. Paris-sud                                      *)
(*                                                                        *)
(*  Secondary contributors:                                               *)
(*                                                                        *)
(*    Thierry HUBERT, Univ. Paris-sud  (former Caduceus front-end)        *)
(*    Nicolas ROUSSET, Univ. Paris-sud (on Jessie & Krakatoa)             *)
(*    Ali AYAD, CNRS & CEA Saclay      (floating-point support)           *)
(*    Sylvie BOLDO, INRIA              (floating-point support)           *)
(*    Jean-Francois COUCHOT, INRIA     (sort encodings, hyps pruning)     *)
(*    Mehdi DOGGUY, Univ. Paris-sud    (Why GUI)                          *)
(*                                                                        *)
(*  This software is free software; you can redistribute it and/or        *)
(*  modify it under the terms of the GNU Lesser General Public            *)
(*  License version 2.1, with the special exception on linking            *)
(*  described in file LICENSE.                                            *)
(*                                                                        *)
(*  This software is distributed in the hope that it will be useful,      *)
(*  but WITHOUT ANY WARRANTY; without even the implied warranty of        *)
(*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.                  *)
(*                                                                        *)
(**************************************************************************)



(*s trees *)

module type Tree = sig

  type t
  val children : t -> t list

  type info
  val info : t -> info
  val show_info : info -> unit

end

(*s trees equipped with navigation functions *)

module type NavTree = sig

  type tree (* type of trees *)
  type t    (* type of navigable trees *)

  val create : tree list -> t

  (* functions to navigate in the tree; 
     must raise [NoMove] when the move is not possible *)
  exception NoMove
  val down : t -> t
  val up : t -> t
  val left : t -> t
  val right : t -> t

  type info
  val info : t -> info
  val show_info : info -> unit

end

(*s functor to add navigation fuctions to a tree *)

module MakeNavTree (T : Tree) : 
  NavTree with type tree = T.t and type info = T.info 

(*s functor to build a navigator *)

module MakeNavigator (T : NavTree) : sig

  val set : T.t -> unit

  val down : unit -> unit
  val up : unit -> unit
  val left : unit -> unit
  val right : unit -> unit

  (* depth-first traversal *)
  val next : unit -> unit

end
