X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Focaml%2Ftactics%2FreductionTactics.ml;fp=helm%2Focaml%2Ftactics%2FreductionTactics.ml;h=115faa80b65a58c88256f0f7cb8d05e8d903002d;hb=792b5d29ebae8f917043d9dd226692919b5d6ca1;hp=0000000000000000000000000000000000000000;hpb=a14a8c7637fd0b95e9d4deccb20c6abc98e8f953;p=helm.git diff --git a/helm/ocaml/tactics/reductionTactics.ml b/helm/ocaml/tactics/reductionTactics.ml new file mode 100644 index 000000000..115faa80b --- /dev/null +++ b/helm/ocaml/tactics/reductionTactics.ml @@ -0,0 +1,220 @@ +(* 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/. + *) + +(* $Id$ *) + +open ProofEngineTypes + +(* Note: this code is almost identical to change_tac and +* it could be unified by making the change function a callback *) +let reduction_tac ~reduction ~pattern (proof,goal) = + let curi,metasenv,pbo,pty = proof in + let (metano,context,ty) as conjecture = CicUtil.lookup_meta goal metasenv in + let change subst where terms metasenv ugraph = + if terms = [] then where, metasenv, ugraph + else + let pairs, metasenv, ugraph = + List.fold_left + (fun (pairs, metasenv, ugraph) (context, t) -> + let reduction, metasenv, ugraph = reduction context metasenv ugraph in + ((t, reduction context t) :: pairs), metasenv, ugraph) + ([], metasenv, ugraph) + terms + in + let terms, terms' = List.split pairs in + let where' = + ProofEngineReduction.replace ~equality:(==) ~what:terms ~with_what:terms' + ~where:where + in + CicMetaSubst.apply_subst subst where', metasenv, ugraph + in + let (subst,metasenv,ugraph,selected_context,selected_ty) = + ProofEngineHelpers.select ~metasenv ~ugraph:CicUniv.empty_ugraph + ~conjecture ~pattern + in + let ty', metasenv, ugraph = change subst ty selected_ty metasenv ugraph in + let context', metasenv, ugraph = + List.fold_right2 + (fun entry selected_entry (context', metasenv, ugraph) -> + match entry,selected_entry with + None,None -> None::context', metasenv, ugraph + | Some (name,Cic.Decl ty),Some (`Decl selected_ty) -> + let ty', metasenv, ugraph = + change subst ty selected_ty metasenv ugraph + in + Some (name,Cic.Decl ty')::context', metasenv, ugraph + | Some (name,Cic.Def (bo,ty)),Some (`Def (selected_bo,selected_ty)) -> + let bo', metasenv, ugraph = + change subst bo selected_bo metasenv ugraph + in + let ty', metasenv, ugraph = + match ty,selected_ty with + None,None -> None, metasenv, ugraph + | Some ty,Some selected_ty -> + let ty', metasenv, ugraph = + change subst ty selected_ty metasenv ugraph + in + Some ty', metasenv, ugraph + | _,_ -> assert false + in + (Some (name,Cic.Def (bo',ty'))::context'), metasenv, ugraph + | _,_ -> assert false + ) context selected_context ([], metasenv, ugraph) in + let metasenv' = + List.map (function + | (n,_,_) when n = metano -> (metano,context',ty') + | _ as t -> t + ) metasenv + in + (curi,metasenv',pbo,pty), [metano] +;; + +let simpl_tac ~pattern = + mk_tactic (reduction_tac + ~reduction:(const_lazy_reduction ProofEngineReduction.simpl) ~pattern) + +let reduce_tac ~pattern = + mk_tactic (reduction_tac + ~reduction:(const_lazy_reduction ProofEngineReduction.reduce) ~pattern) + +let unfold_tac what ~pattern = + let reduction = + match what with + | None -> const_lazy_reduction (ProofEngineReduction.unfold ?what:None) + | Some lazy_term -> + (fun context metasenv ugraph -> + let what, metasenv, ugraph = lazy_term context metasenv ugraph in + ProofEngineReduction.unfold ~what, metasenv, ugraph) + in + mk_tactic (reduction_tac ~reduction ~pattern) + +let whd_tac ~pattern = + mk_tactic (reduction_tac + ~reduction:(const_lazy_reduction CicReduction.whd) ~pattern) + +let normalize_tac ~pattern = + mk_tactic (reduction_tac + ~reduction:(const_lazy_reduction CicReduction.normalize) ~pattern) + +exception NotConvertible + +(* Note: this code is almost identical to reduction_tac and +* it could be unified by making the change function a callback *) +(* CSC: with_what is parsed in the context of the goal, but it should replace + something that lives in a completely different context. Thus we + perform a delift + lift phase to move it in the right context. However, + in this way the tactic is less powerful than expected: with_what cannot + reference variables that are local to the term that is going to be + replaced. To fix this we should parse with_what in the context of the + term(s) to be replaced. *) +let change_tac ~pattern with_what = + let change_tac ~pattern ~with_what (proof, goal) = + let curi,metasenv,pbo,pty = proof in + let (metano,context,ty) as conjecture = CicUtil.lookup_meta goal metasenv in + let change subst where terms metasenv ugraph = + if terms = [] then where, metasenv, ugraph + else + let pairs, metasenv, ugraph = + List.fold_left + (fun (pairs, metasenv, ugraph) (context_of_t, t) -> + let with_what, metasenv, ugraph = + with_what context_of_t metasenv ugraph + in + let _,u = + CicTypeChecker.type_of_aux' metasenv context_of_t with_what ugraph + in + let b,_ = + CicReduction.are_convertible ~metasenv context_of_t t with_what u + in + if b then + ((t, with_what) :: pairs), metasenv, ugraph + else + raise NotConvertible) + ([], metasenv, ugraph) + terms + in + let terms, terms' = List.split pairs in + let where' = + ProofEngineReduction.replace ~equality:(==) ~what:terms ~with_what:terms' + ~where:where + in + CicMetaSubst.apply_subst subst where', metasenv, ugraph + in + let (subst,metasenv,ugraph,selected_context,selected_ty) = + ProofEngineHelpers.select ~metasenv ~ugraph:CicUniv.empty_ugraph ~conjecture + ~pattern in + let ty', metasenv, ugraph = change subst ty selected_ty metasenv ugraph in + let context', metasenv, ugraph = + List.fold_right2 + (fun entry selected_entry (context', metasenv, ugraph) -> + match entry,selected_entry with + None,None -> (None::context'), metasenv, ugraph + | Some (name,Cic.Decl ty),Some (`Decl selected_ty) -> + let ty', metasenv, ugraph = + change subst ty selected_ty metasenv ugraph + in + (Some (name,Cic.Decl ty')::context'), metasenv, ugraph + | Some (name,Cic.Def (bo,ty)),Some (`Def (selected_bo,selected_ty)) -> + let bo', metasenv, ugraph = + change subst bo selected_bo metasenv ugraph + in + let ty', metasenv, ugraph = + match ty,selected_ty with + None,None -> None, metasenv, ugraph + | Some ty,Some selected_ty -> + let ty', metasenv, ugraph = + change subst ty selected_ty metasenv ugraph + in + Some ty', metasenv, ugraph + | _,_ -> assert false + in + (Some (name,Cic.Def (bo',ty'))::context'), metasenv, ugraph + | _,_ -> assert false + ) context selected_context ([], metasenv, ugraph) in + let metasenv' = + List.map + (function + | (n,_,_) when n = metano -> (metano,context',ty') + | _ as t -> t) + metasenv + in + (curi,metasenv',pbo,pty), [metano] + in + mk_tactic (change_tac ~pattern ~with_what) + +let fold_tac ~reduction ~term ~pattern = + let fold_tac ~reduction ~term ~pattern:(wanted,hyps_pat,concl_pat) status = + assert (wanted = None); (* this should be checked syntactically *) + let reduced_term = + (fun context metasenv ugraph -> + let term, metasenv, ugraph = term context metasenv ugraph in + let reduction, metasenv, ugraph = reduction context metasenv ugraph in + reduction context term, metasenv, ugraph) + in + apply_tactic + (change_tac ~pattern:(Some reduced_term,hyps_pat,concl_pat) term) status + in + mk_tactic (fold_tac ~reduction ~term ~pattern) +