1 (* Copyright (C) 2002, HELM Team.
3 * This file is part of HELM, an Hypertextual, Electronic
4 * Library of Mathematics, developed at the Computer Science
5 * Department, University of Bologna, Italy.
7 * HELM is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2
10 * of the License, or (at your option) any later version.
12 * HELM is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with HELM; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
22 * For details, see the HELM World-Wide-Web page,
23 * http://cs.unibo.it/helm/.
27 let absurd_tac ~term status =
28 let (proof, goal) = status in
30 let module U = UriManager in
31 let module P = PrimitiveTactics in
32 let _,metasenv,_,_ = proof in
33 let _,context,ty = CicUtil.lookup_meta goal metasenv in
34 if ((CicTypeChecker.type_of_aux' metasenv context term) = (C.Sort C.Prop)) (* ma questo controllo serve?? *)
36 ~term:(C.Appl [(C.Const (HelmLibraryObjects.Logic.absurd_URI , [] )) ; term ; ty]) status
37 else raise (ProofEngineTypes.Fail "Absurd: Not a Proposition")
41 let contradiction_tac status =
43 let module U = UriManager in
44 let module P = PrimitiveTactics in
45 let module T = Tacticals in
48 ~start:(P.intros_tac ())
52 (EliminationTactics.elim_type_tac
54 (C.MutInd (HelmLibraryObjects.Logic.false_URI, 0, [])))
55 ~continuation: VariousTactics.assumption_tac)
58 (ProofEngineTypes.Fail "Assumption: No such assumption") -> raise (ProofEngineTypes.Fail "Contradiction: No such assumption")
59 (* sarebbe piu' elegante se Assumtion sollevasse un'eccezione tutta sua che questa cattura, magari con l'aiuto di try_tactics *)
62 (* Questa era in fourierR.ml
63 (* !!!!! fix !!!!!!!!!! *)
64 let contradiction_tac (proof,goal)=
66 ~start:(PrimitiveTactics.intros_tac ~name:"bo?" ) (*inutile sia questo che quello prima della chiamata*)
67 ~continuation:(Tacticals.then_
68 ~start:(VariousTactics.elim_type_tac ~term:_False)
69 ~continuation:(assumption_tac))