branch for universe

[helm.git] / components / tactics / universe.ml

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+(* Copyright (C) 2002, 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/.
+ *)
+
+module Codomain = struct 
+  type t = Cic.term 
+  let compare = Pervasives.compare 
+end
+module S = Set.Make(Codomain)
+module TI = Discrimination_tree.DiscriminationTreeIndexing(S)
+type universe = TI.t
+
+let empty = TI.empty
+;;
+
+let get_candidates univ ty = 
+  S.elements (TI.retrieve_unifiables univ ty)
+;;
+
+let rec unfold context = function
+  | Cic.Prod(name,s,t) -> 
+      let t' = unfold ((Some (name,Cic.Decl s))::context) t in
+        Cic.Prod(name,s,t')        
+  | t -> ProofEngineReduction.unfold context t
+
+let rec collapse_head_metas t = 
+  match t with
+    | Cic.Appl([]) -> assert false
+    | Cic.Appl(a::l) -> 
+       let a' = collapse_head_metas a in
+         (match a' with
+            | Cic.Meta(n,m) -> Cic.Meta(n,m)
+            | t ->     
+                let l' = List.map collapse_head_metas l in
+                  Cic.Appl(t::l'))
+    | Cic.Rel _ 
+    | Cic.Var _         
+    | Cic.Meta _ 
+    | Cic.Sort _ 
+    | Cic.Implicit _
+    | Cic.Const _ 
+    | Cic.MutInd _
+    | Cic.MutConstruct _ -> t
+    | Cic.LetIn _
+    | Cic.Lambda _
+    | Cic.Prod _
+    | Cic.Cast _
+    | Cic.MutCase _
+    | Cic.Fix _
+    | Cic.CoFix _ -> Cic.Meta(-1,[])
+;;
+
+let rec dummies_of_coercions = 
+  function
+    | Cic.Appl (c::l) when CoercDb.is_a_coercion' c ->
+        Cic.Meta (-1,[])
+    | Cic.Appl l -> 
+        let l' = List.map dummies_of_coercions l in Cic.Appl l'
+    | Cic.Lambda(n,s,t) ->
+        let s' = dummies_of_coercions s in
+        let t' = dummies_of_coercions t in
+          Cic.Lambda (n,s',t')
+    | Cic.Prod(n,s,t) ->
+        let s' = dummies_of_coercions s in
+        let t' = dummies_of_coercions t in
+          Cic.Prod (n,s',t')        
+    | Cic.LetIn(n,s,ty,t) ->
+        let s' = dummies_of_coercions s in
+        let ty' = dummies_of_coercions ty in
+        let t' = dummies_of_coercions t in
+          Cic.LetIn (n,s',ty',t')        
+    | Cic.MutCase _ -> Cic.Meta (-1,[])
+    | t -> t
+;;
+
+
+let rec head remove_coercions t = 
+  let clean_up t =
+    if remove_coercions then dummies_of_coercions t
+    else t in
+  let rec aux = function
+  | Cic.Prod(_,_,t) -> 
+      CicSubstitution.subst (Cic.Meta (-1,[])) (aux t)
+  | t -> t
+  in collapse_head_metas (clean_up (aux t))
+;;
+
+
+let index univ key term =
+  (* flexible terms are not indexed *)
+  if key = Cic.Meta(-1,[]) then univ
+  else
+    ((*prerr_endline("ADD: "^CicPp.ppterm key^" |-> "^CicPp.ppterm term);*)
+     TI.index univ key term)
+;;
+
+let keys context ty =
+  try
+    [head true ty; head true (unfold context ty)]
+  with ProofEngineTypes.Fail _ -> [head true ty]
+
+let key term = head false term;;
+
+let index_term_and_unfolded_term univ context t ty =
+  let key = head true ty in
+  let univ = index univ key t in
+  try  
+    let key = head true (unfold context ty) in
+    index univ key t
+  with ProofEngineTypes.Fail _ -> univ
+;;
+
+let index_local_term univ context t ty =
+  let key = head true ty in
+  let univ = index univ key t in
+  let key1 = head false ty in
+  let univ =
+    if key<>key1 then index univ key1 t else univ in
+  try  
+    let key = head true (unfold context ty) in
+    index univ key t
+  with ProofEngineTypes.Fail _ -> univ
+;;
+
+
+let index_list univ context terms_and_types =
+  List.fold_left  
+    (fun acc (term,ty) -> 
+       index_term_and_unfolded_term acc context term ty)
+    univ terms_and_types
+
+;;
+
+let remove univ context term ty =
+  let key = head true ty in
+  let univ = TI.remove_index univ key term in
+  try  
+    let key = head true (unfold context ty) in
+    TI.remove_index univ key term
+  with ProofEngineTypes.Fail _ -> univ
+
+let remove_uri univ uri =
+  let term = CicUtil.term_of_uri uri in
+  let ty,_ = CicTypeChecker.type_of_aux' [] [] term CicUniv.empty_ugraph in
+    remove univ [] term ty
+
+