(* Copyright (C) 2005, HELM Team.
 * 
 * This file is part of HELM, an Hypertextual, Electronic
 * Library of Mathematics, developed at the Computer Science
 * Department, University of Bologna, Italy.
 * 
 * HELM is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * HELM 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.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HELM; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA  02111-1307, USA.
 * 
 * For details, see the HELM World-Wide-Web page,
 * http://cs.unibo.it/helm/.
 *)

exception MatchingFailure

(** matching between two terms. Can raise MatchingFailure *)
val matching:
  Cic.metasenv -> Cic.metasenv -> Cic.context -> 
  Cic.term -> Cic.term ->
  CicUniv.universe_graph ->
    Subst.substitution * Cic.metasenv * CicUniv.universe_graph

(**
   special unification that checks if the two terms are "simple", and in
   such case should be significantly faster than CicUnification.fo_unif
*)
val unification:
  Cic.metasenv -> Cic.metasenv -> Cic.context -> 
  Cic.term -> Cic.term ->
  CicUniv.universe_graph ->
    Subst.substitution * Cic.metasenv * CicUniv.universe_graph

    
(**
   scans the context to find all Declarations "left = right"; returns a
   list of tuples (proof, (type, left, right), newmetas). Uses
   PrimitiveTactics.new_metasenv_for_apply to replace bound variables with
   fresh metas...
*)
val find_equalities:
  Cic.context -> ProofEngineTypes.proof -> 
    int list * Equality.equality list * int

(**
   searches the library for equalities that can be applied to the current goal
*)
val find_library_equalities:
  HMysql.dbd -> Cic.context -> ProofEngineTypes.status -> int ->
    UriManager.UriSet.t * (UriManager.uri * Equality.equality) list * int

(**
   searches the library for theorems that are not equalities (returned by the
   function above)
*)
val find_library_theorems:
  HMysql.dbd -> Utils.environment -> ProofEngineTypes.status -> 
  UriManager.UriSet.t ->
    (Cic.term * Cic.term * Cic.metasenv) list

(**
   searches the context for hypotheses that are not equalities
*)
val find_context_hypotheses:
  Utils.environment -> int list -> (Cic.term * Cic.term * Cic.metasenv) list

val get_stats: unit -> string