-
-let rewrite_tac ~term:equality ~status:(proof,goal) =
- let module C = Cic in
- let module U = UriManager in
- let curi,metasenv,pbo,pty = proof in
- let metano,context,gty = CicUtil.lookup_meta goal metasenv in
- let eq_ind_r,ty,t1,t2 =
- match CicTypeChecker.type_of_aux' metasenv context equality with
- C.Appl [C.MutInd (uri,0,[]) ; ty ; t1 ; t2]
- when U.eq uri HelmLibraryObjects.Logic.eq_URI ->
- let eq_ind_r =
- C.Const
- (HelmLibraryObjects.Logic.eq_ind_r_URI,[])
- in
- eq_ind_r,ty,t1,t2
- | _ ->
- raise
- (ProofEngineTypes.Fail
- "Rewrite: the argument is not a proof of an equality")
- in
- let pred =
- let gty' = CicSubstitution.lift 1 gty in
- let t1' = CicSubstitution.lift 1 t1 in
- let gty'' =
- ProofEngineReduction.replace_lifting
- ~equality:ProofEngineReduction.alpha_equivalence
- ~what:[t1'] ~with_what:[C.Rel 1] ~where:gty'
- in
- C.Lambda
- (FreshNamesGenerator.mk_fresh_name metasenv context C.Anonymous ty,
- ty, gty'')
- in
- let fresh_meta = ProofEngineHelpers.new_meta_of_proof proof in
- let irl = CicMkImplicit.identity_relocation_list_for_metavariable context in
- let metasenv' = (fresh_meta,context,C.Appl [pred ; t2])::metasenv in
-
- let (proof',goals) =
- PrimitiveTactics.exact_tac
- ~term:(C.Appl
- [eq_ind_r ; ty ; t2 ; pred ; C.Meta (fresh_meta,irl) ; t1 ;equality])
- ~status:((curi,metasenv',pbo,pty),goal)
- in
- assert (List.length goals = 0) ;
- (proof',[fresh_meta])
-;;
-
-
-let rewrite_simpl_tac ~term ~status =
- Tacticals.then_
- ~start:(rewrite_tac ~term)
- ~continuation:
- (ReductionTactics.simpl_tac ~also_in_hypotheses:false ~terms:None)
- ~status
-;;
-
-
-let rewrite_back_tac ~term:equality ~status:(proof,goal) =
- let module C = Cic in
- let module U = UriManager in
- let curi,metasenv,pbo,pty = proof in
- let metano,context,gty = CicUtil.lookup_meta goal metasenv in
- let eq_ind_r,ty,t1,t2 =
- match CicTypeChecker.type_of_aux' metasenv context equality with
- C.Appl [C.MutInd (uri,0,[]) ; ty ; t1 ; t2]
- when U.eq uri HelmLibraryObjects.Logic.eq_URI ->
- let eq_ind_r =
- C.Const (HelmLibraryObjects.Logic.eq_ind_URI,[])
- in
- eq_ind_r,ty,t2,t1
- | _ ->
- raise
- (ProofEngineTypes.Fail
- "Rewrite: the argument is not a proof of an equality")
- in
- let pred =
- let gty' = CicSubstitution.lift 1 gty in
- let t1' = CicSubstitution.lift 1 t1 in
- let gty'' =
- ProofEngineReduction.replace_lifting
- ~equality:ProofEngineReduction.alpha_equivalence
- ~what:[t1'] ~with_what:[C.Rel 1] ~where:gty'
- in
- C.Lambda
- (FreshNamesGenerator.mk_fresh_name metasenv context C.Anonymous ty,
- ty, gty'')
+let rewrite ~term:equality ?where ?(direction=`Left) (proof,goal) =
+ let module C = Cic in
+ let module U = UriManager in
+ let module PET = ProofEngineTypes in
+ let module PER = ProofEngineReduction in
+ let module PEH = ProofEngineHelpers in
+ let module PT = PrimitiveTactics in
+ let module HLO = HelmLibraryObjects in
+ let if_left a b =
+ match direction with
+ | `Right -> b
+ | `Left -> a
+ in
+ let curi, metasenv, pbo, pty = proof in
+ let metano, context, gty = CicUtil.lookup_meta goal metasenv in
+ let eq_uri = HLO.Logic.eq_URI in
+ let ty_eq,_ =
+ CicTypeChecker.type_of_aux' metasenv context equality
+ CicUniv.empty_ugraph
+ in
+ let eq_ind, ty, t1, t2 =
+ match ty_eq with
+ | C.Appl [C.MutInd (uri, 0, []); ty; t1; t2] when U.eq uri eq_uri ->
+ let eq_ind =
+ C.Const (if_left HLO.Logic.eq_ind_URI HLO.Logic.eq_ind_r_URI,[])
+ in
+ if_left (eq_ind, ty, t2, t1) (eq_ind, ty, t1, t2)
+ | _ -> raise (PET.Fail "Rewrite: argument is not a proof of an equality")
+ in
+ (* now we always do as if direction was `Left *)
+ let gty' = CicSubstitution.lift 1 gty in
+ let t1' = CicSubstitution.lift 1 t1 in
+ let eq_kind, what =
+ match where with
+ | None
+ | Some ([], None) ->
+ PER.alpha_equivalence, [t1']
+ | Some (hp_paths, goal_path) ->
+ assert (hp_paths = []);
+ match goal_path with
+ | None -> assert false (* (==), [t1'] *)
+ | Some path ->
+ let roots = ProofEngineHelpers.select ~term:gty' ~pattern:path in
+ let subterms =
+ List.fold_left (
+ fun acc (i, r) ->
+ let wanted = CicSubstitution.lift (List.length i) t1' in
+ PEH.find_subterms ~eq:PER.alpha_equivalence ~wanted r @ acc
+ ) [] roots
+ in
+ (==), subterms
+ in
+ let with_what =
+ let rec aux = function
+ | 0 -> []
+ | n -> C.Rel 1 :: aux (n-1)