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/.
26 open ProofEngineHelpers
29 exception NotAnInductiveTypeToEliminate
30 exception NotTheRightEliminatorShape
31 exception NoHypothesesFound
32 exception WrongUriToVariable of string
34 (* lambda_abstract newmeta ty *)
35 (* returns a triple [bo],[context],[ty'] where *)
36 (* [ty] = Pi/LetIn [context].[ty'] ([context] is a vector!) *)
37 (* and [bo] = Lambda/LetIn [context].(Meta [newmeta]) *)
38 (* So, lambda_abstract is the core of the implementation of *)
39 (* the Intros tactic. *)
40 (* howmany = -1 means Intros, howmany > 0 means Intros n *)
41 let lambda_abstract ?(howmany=(-1)) metasenv context newmeta ty mk_fresh_name =
43 let rec collect_context context howmany ty =
47 CicMkImplicit.identity_relocation_list_for_metavariable context
49 context, ty, (C.Meta (newmeta,irl))
52 C.Cast (te,_) -> collect_context context howmany te
54 let n' = mk_fresh_name metasenv context n ~typ:s in
55 let (context',ty,bo) =
56 collect_context ((Some (n',(C.Decl s)))::context) (howmany - 1) t
58 (context',ty,C.Lambda(n',s,bo))
60 let (context',ty,bo) =
61 collect_context ((Some (n,(C.Def (s,None))))::context) (howmany - 1) t
63 (context',ty,C.LetIn(n,s,bo))
66 CicMkImplicit.identity_relocation_list_for_metavariable context
68 context, t, (C.Meta (newmeta,irl))
70 collect_context context howmany ty
72 let eta_expand metasenv context t arg =
73 let module T = CicTypeChecker in
74 let module S = CicSubstitution in
78 t' when t' = S.lift n arg -> C.Rel (1 + n)
79 | C.Rel m -> if m <= n then C.Rel m else C.Rel (m+1)
80 | C.Var (uri,exp_named_subst) ->
81 let exp_named_subst' = aux_exp_named_subst n exp_named_subst in
82 C.Var (uri,exp_named_subst')
85 List.map (function None -> None | Some t -> Some (aux n t)) l
89 | C.Implicit _ as t -> t
90 | C.Cast (te,ty) -> C.Cast (aux n te, aux n ty)
91 | C.Prod (nn,s,t) -> C.Prod (nn, aux n s, aux (n+1) t)
92 | C.Lambda (nn,s,t) -> C.Lambda (nn, aux n s, aux (n+1) t)
93 | C.LetIn (nn,s,t) -> C.LetIn (nn, aux n s, aux (n+1) t)
94 | C.Appl l -> C.Appl (List.map (aux n) l)
95 | C.Const (uri,exp_named_subst) ->
96 let exp_named_subst' = aux_exp_named_subst n exp_named_subst in
97 C.Const (uri,exp_named_subst')
98 | C.MutInd (uri,i,exp_named_subst) ->
99 let exp_named_subst' = aux_exp_named_subst n exp_named_subst in
100 C.MutInd (uri,i,exp_named_subst')
101 | C.MutConstruct (uri,i,j,exp_named_subst) ->
102 let exp_named_subst' = aux_exp_named_subst n exp_named_subst in
103 C.MutConstruct (uri,i,j,exp_named_subst')
104 | C.MutCase (sp,i,outt,t,pl) ->
105 C.MutCase (sp,i,aux n outt, aux n t,
108 let tylen = List.length fl in
111 (fun (name,i,ty,bo) -> (name, i, aux n ty, aux (n+tylen) bo))
114 C.Fix (i, substitutedfl)
116 let tylen = List.length fl in
119 (fun (name,ty,bo) -> (name, aux n ty, aux (n+tylen) bo))
122 C.CoFix (i, substitutedfl)
123 and aux_exp_named_subst n =
124 List.map (function uri,t -> uri,aux n t)
127 T.type_of_aux' metasenv context arg CicUniv.empty_ugraph (* TASSI: FIXME *)
130 FreshNamesGenerator.mk_fresh_name ~subst:[]
131 metasenv context (Cic.Name "Heta") ~typ:argty
133 (C.Appl [C.Lambda (fresh_name,argty,aux 0 t) ; arg])
135 (*CSC: ma serve solamente la prima delle new_uninst e l'unione delle due!!! *)
136 let classify_metas newmeta in_subst_domain subst_in metasenv =
138 (fun (i,canonical_context,ty) (old_uninst,new_uninst) ->
139 if in_subst_domain i then
140 old_uninst,new_uninst
142 let ty' = subst_in canonical_context ty in
143 let canonical_context' =
145 (fun entry canonical_context' ->
148 Some (n,Cic.Decl s) ->
149 Some (n,Cic.Decl (subst_in canonical_context' s))
150 | Some (n,Cic.Def (s,None)) ->
151 Some (n,Cic.Def ((subst_in canonical_context' s),None))
153 | Some (_,Cic.Def (_,Some _)) -> assert false
155 entry'::canonical_context'
156 ) canonical_context []
159 ((i,canonical_context',ty')::old_uninst),new_uninst
161 old_uninst,((i,canonical_context',ty')::new_uninst)
164 (* Auxiliary function for apply: given a type (a backbone), it returns its *)
165 (* head, a META environment in which there is new a META for each hypothesis,*)
166 (* a list of arguments for the new applications and the indexes of the first *)
167 (* and last new METAs introduced. The nth argument in the list of arguments *)
168 (* is just the nth new META. *)
169 let new_metasenv_for_apply newmeta proof context ty =
170 let module C = Cic in
171 let module S = CicSubstitution in
172 let rec aux newmeta ty =
173 let ty' = (*CicReduction.whd context*) ty in
175 C.Cast (he,_) -> aux newmeta he
176 (* CSC: patch to generate ?1 : ?2 : Type in place of ?1 : Type to simulate ?1 :< Type
177 (* If the expected type is a Type, then also Set is OK ==>
178 * we accept any term of type Type *)
179 (*CSC: BUG HERE: in this way it is possible for the term of
180 * type Type to be different from a Sort!!! *)
181 | C.Prod (name,(C.Sort (C.Type _) as s),t) ->
182 (* TASSI: ask CSC if BUG HERE refers to the C.Cast or C.Propd case *)
184 CicMkImplicit.identity_relocation_list_for_metavariable context
186 let newargument = C.Meta (newmeta+1,irl) in
187 let (res,newmetasenv,arguments,lastmeta) =
188 aux (newmeta + 2) (S.subst newargument t)
191 (newmeta,[],s)::(newmeta+1,context,C.Meta (newmeta,[]))::newmetasenv,
192 newargument::arguments,lastmeta
194 | C.Prod (name,s,t) ->
196 CicMkImplicit.identity_relocation_list_for_metavariable context
198 let newargument = C.Meta (newmeta,irl) in
199 let (res,newmetasenv,arguments,lastmeta) =
200 aux (newmeta + 1) (S.subst newargument t)
202 res,(newmeta,context,s)::newmetasenv,newargument::arguments,lastmeta
203 | t -> t,[],[],newmeta
205 (* WARNING: here we are using the invariant that above the most *)
206 (* recente new_meta() there are no used metas. *)
207 let (res,newmetasenv,arguments,lastmeta) = aux newmeta ty in
208 res,newmetasenv,arguments,lastmeta
210 (* Useful only inside apply_tac *)
212 generalize_exp_named_subst_with_fresh_metas context newmeta uri exp_named_subst
214 let module C = Cic in
216 let o,_ = CicEnvironment.get_obj CicUniv.empty_ugraph uri in
217 CicUtil.params_of_obj o
219 let exp_named_subst_diff,new_fresh_meta,newmetasenvfragment,exp_named_subst'=
220 let next_fresh_meta = ref newmeta in
221 let newmetasenvfragment = ref [] in
222 let exp_named_subst_diff = ref [] in
228 let o,_ = CicEnvironment.get_obj CicUniv.empty_ugraph uri in
230 C.Variable (_,_,ty,_,_) ->
231 CicSubstitution.subst_vars !exp_named_subst_diff ty
232 | _ -> raise (WrongUriToVariable (UriManager.string_of_uri uri))
234 (* CSC: patch to generate ?1 : ?2 : Type in place of ?1 : Type to simulate ?1 :< Type
236 C.Sort (C.Type _) as s -> (* TASSI: ?? *)
237 let fresh_meta = !next_fresh_meta in
238 let fresh_meta' = fresh_meta + 1 in
239 next_fresh_meta := !next_fresh_meta + 2 ;
240 let subst_item = uri,C.Meta (fresh_meta',[]) in
241 newmetasenvfragment :=
242 (fresh_meta,[],C.Sort (C.Type (CicUniv.fresh()))) ::
244 (fresh_meta',[],C.Meta (fresh_meta,[])) :: !newmetasenvfragment ;
245 exp_named_subst_diff := !exp_named_subst_diff @ [subst_item] ;
246 subst_item::(aux (tl,[]))
250 CicMkImplicit.identity_relocation_list_for_metavariable context
252 let subst_item = uri,C.Meta (!next_fresh_meta,irl) in
253 newmetasenvfragment :=
254 (!next_fresh_meta,context,ty)::!newmetasenvfragment ;
255 exp_named_subst_diff := !exp_named_subst_diff @ [subst_item] ;
256 incr next_fresh_meta ;
257 subst_item::(aux (tl,[]))(*)*)
258 | uri::tl1,((uri',_) as s)::tl2 ->
259 assert (UriManager.eq uri uri') ;
261 | [],_ -> assert false
263 let exp_named_subst' = aux (params,exp_named_subst) in
264 !exp_named_subst_diff,!next_fresh_meta,
265 List.rev !newmetasenvfragment, exp_named_subst'
267 new_fresh_meta,newmetasenvfragment,exp_named_subst',exp_named_subst_diff
270 let new_metasenv_and_unify_and_t newmeta' metasenv' proof context term' ty termty =
271 let (consthead,newmetas,arguments,_) =
272 new_metasenv_for_apply newmeta' proof context termty
274 let newmetasenv = metasenv'@newmetas in
275 let subst,newmetasenv',_ =
276 CicUnification.fo_unif newmetasenv context consthead ty CicUniv.empty_ugraph
279 if List.length newmetas = 0 then term' else Cic.Appl (term'::arguments)
283 let apply_tac_verbose ~term (proof, goal) =
284 (* Assumption: The term "term" must be closed in the current context *)
285 let module T = CicTypeChecker in
286 let module R = CicReduction in
287 let module C = Cic in
288 let (_,metasenv,_,_) = proof in
289 let metano,context,ty = CicUtil.lookup_meta goal metasenv in
290 let newmeta = new_meta_of_proof ~proof in
291 let exp_named_subst_diff,newmeta',newmetasenvfragment,term' =
293 C.Var (uri,exp_named_subst) ->
294 let newmeta',newmetasenvfragment,exp_named_subst',exp_named_subst_diff =
295 generalize_exp_named_subst_with_fresh_metas context newmeta uri
298 exp_named_subst_diff,newmeta',newmetasenvfragment,
299 C.Var (uri,exp_named_subst')
300 | C.Const (uri,exp_named_subst) ->
301 let newmeta',newmetasenvfragment,exp_named_subst',exp_named_subst_diff =
302 generalize_exp_named_subst_with_fresh_metas context newmeta uri
305 exp_named_subst_diff,newmeta',newmetasenvfragment,
306 C.Const (uri,exp_named_subst')
307 | C.MutInd (uri,tyno,exp_named_subst) ->
308 let newmeta',newmetasenvfragment,exp_named_subst',exp_named_subst_diff =
309 generalize_exp_named_subst_with_fresh_metas context newmeta uri
312 exp_named_subst_diff,newmeta',newmetasenvfragment,
313 C.MutInd (uri,tyno,exp_named_subst')
314 | C.MutConstruct (uri,tyno,consno,exp_named_subst) ->
315 let newmeta',newmetasenvfragment,exp_named_subst',exp_named_subst_diff =
316 generalize_exp_named_subst_with_fresh_metas context newmeta uri
319 exp_named_subst_diff,newmeta',newmetasenvfragment,
320 C.MutConstruct (uri,tyno,consno,exp_named_subst')
321 | _ -> [],newmeta,[],term
323 let metasenv' = metasenv@newmetasenvfragment in
325 CicTypeChecker.type_of_aux' metasenv' context term CicUniv.empty_ugraph in
327 CicSubstitution.subst_vars exp_named_subst_diff termty
329 let subst,newmetasenv',t =
331 new_metasenv_and_unify_and_t newmeta' metasenv' proof context term' ty
333 with CicUnification.UnificationFailure _ ->
334 new_metasenv_and_unify_and_t newmeta' metasenv' proof context term' ty
335 (CicReduction.whd context termty)
337 let in_subst_domain i = List.exists (function (j,_) -> i=j) subst in
338 let apply_subst = CicMetaSubst.apply_subst subst in
339 let old_uninstantiatedmetas,new_uninstantiatedmetas =
340 (* subst_in doesn't need the context. Hence the underscore. *)
341 let subst_in _ = CicMetaSubst.apply_subst subst in
342 classify_metas newmeta in_subst_domain subst_in newmetasenv'
344 let bo' = apply_subst t in
345 let newmetasenv'' = new_uninstantiatedmetas@old_uninstantiatedmetas in
347 (* if we just apply the subtitution, the type is irrelevant:
348 we may use Implicit, since it will be dropped *)
349 CicMetaSubst.apply_subst ((metano,(context,bo',Cic.Implicit None))::subst)
351 let (newproof, newmetasenv''') =
352 subst_meta_and_metasenv_in_proof proof metano subst_in newmetasenv''
356 List.map (function (i,_,_) -> i) new_uninstantiatedmetas))
358 let apply_tac ~term status = snd (apply_tac_verbose ~term status)
360 let apply_tac_verbose ~term status =
362 apply_tac_verbose ~term status
363 (* TODO cacciare anche altre eccezioni? *)
364 with CicUnification.UnificationFailure _ as e ->
365 raise (Fail (Printexc.to_string e))
367 (* TODO per implementare i tatticali e' necessario che tutte le tattiche
368 sollevino _solamente_ Fail *)
369 let apply_tac ~term =
370 let apply_tac ~term status =
372 apply_tac ~term status
373 (* TODO cacciare anche altre eccezioni? *)
374 with CicUnification.UnificationFailure _ as e ->
375 raise (Fail (Printexc.to_string e))
377 mk_tactic (apply_tac ~term)
379 let intros_tac ?howmany ?(mk_fresh_name_callback = FreshNamesGenerator.mk_fresh_name ~subst:[]) ()=
381 ?(mk_fresh_name_callback = (FreshNamesGenerator.mk_fresh_name ~subst:[])) ()
384 let module C = Cic in
385 let module R = CicReduction in
386 let (_,metasenv,_,_) = proof in
387 let metano,context,ty = CicUtil.lookup_meta goal metasenv in
388 let newmeta = new_meta_of_proof ~proof in
389 let (context',ty',bo') =
390 lambda_abstract ?howmany metasenv context newmeta ty mk_fresh_name_callback
393 subst_meta_in_proof proof metano bo' [newmeta,context',ty']
395 (newproof, [newmeta])
397 mk_tactic (intros_tac ~mk_fresh_name_callback ())
399 let cut_tac?(mk_fresh_name_callback = FreshNamesGenerator.mk_fresh_name ~subst:[]) ~term=
401 ?(mk_fresh_name_callback = FreshNamesGenerator.mk_fresh_name ~subst:[])
404 let module C = Cic in
405 let curi,metasenv,pbo,pty = proof in
406 let metano,context,ty = CicUtil.lookup_meta goal metasenv in
407 let newmeta1 = new_meta_of_proof ~proof in
408 let newmeta2 = newmeta1 + 1 in
410 mk_fresh_name_callback metasenv context (Cic.Name "Hcut") ~typ:term in
411 let context_for_newmeta1 =
412 (Some (fresh_name,C.Decl term))::context in
414 CicMkImplicit.identity_relocation_list_for_metavariable
418 CicMkImplicit.identity_relocation_list_for_metavariable context
420 let newmeta1ty = CicSubstitution.lift 1 ty in
423 [C.Lambda (fresh_name,term,C.Meta (newmeta1,irl1)) ;
424 C.Meta (newmeta2,irl2)]
427 subst_meta_in_proof proof metano bo'
428 [newmeta2,context,term; newmeta1,context_for_newmeta1,newmeta1ty];
430 (newproof, [newmeta1 ; newmeta2])
432 mk_tactic (cut_tac ~mk_fresh_name_callback term)
434 let letin_tac ?(mk_fresh_name_callback=FreshNamesGenerator.mk_fresh_name ~subst:[]) ~term=
436 ?(mk_fresh_name_callback = FreshNamesGenerator.mk_fresh_name ~subst:[])
439 let module C = Cic in
440 let curi,metasenv,pbo,pty = proof in
441 let metano,context,ty = CicUtil.lookup_meta goal metasenv in
442 let _,_ = (* TASSI: FIXME *)
443 CicTypeChecker.type_of_aux' metasenv context term CicUniv.empty_ugraph in
444 let newmeta = new_meta_of_proof ~proof in
446 mk_fresh_name_callback metasenv context (Cic.Name "Hletin") ~typ:term in
447 let context_for_newmeta =
448 (Some (fresh_name,C.Def (term,None)))::context in
450 CicMkImplicit.identity_relocation_list_for_metavariable
453 let newmetaty = CicSubstitution.lift 1 ty in
454 let bo' = C.LetIn (fresh_name,term,C.Meta (newmeta,irl)) in
457 proof metano bo'[newmeta,context_for_newmeta,newmetaty]
459 (newproof, [newmeta])
461 mk_tactic (letin_tac ~mk_fresh_name_callback term)
463 (** functional part of the "exact" tactic *)
464 let exact_tac ~term =
465 let exact_tac ~term (proof, goal) =
466 (* Assumption: the term bo must be closed in the current context *)
467 let (_,metasenv,_,_) = proof in
468 let metano,context,ty = CicUtil.lookup_meta goal metasenv in
469 let module T = CicTypeChecker in
470 let module R = CicReduction in
471 let ty_term,u = T.type_of_aux' metasenv context term CicUniv.empty_ugraph in
472 let b,_ = R.are_convertible context ty_term ty u in (* TASSI: FIXME *)
475 let (newproof, metasenv') =
476 subst_meta_in_proof proof metano term [] in
480 raise (Fail "The type of the provided term is not the one expected.")
482 mk_tactic (exact_tac ~term)
484 (* not really "primitive" tactics .... *)
486 let elim_tac ~term (proof, goal) =
487 let module T = CicTypeChecker in
488 let module U = UriManager in
489 let module R = CicReduction in
490 let module C = Cic in
491 let (curi,metasenv,proofbo,proofty) = proof in
492 let metano,context,ty = CicUtil.lookup_meta goal metasenv in
493 let termty,_ = T.type_of_aux' metasenv context term CicUniv.empty_ugraph in
495 let uri,exp_named_subst,typeno,args =
497 C.MutInd (uri,typeno,exp_named_subst) -> (uri,exp_named_subst,typeno,[])
498 | C.Appl ((C.MutInd (uri,typeno,exp_named_subst))::args) ->
499 (uri,exp_named_subst,typeno,args)
500 | _ -> raise NotAnInductiveTypeToEliminate
503 let buri = U.buri_of_uri uri in
505 let o,_ = CicEnvironment.get_obj CicUniv.empty_ugraph uri in
507 C.InductiveDefinition (tys,_,_,_) ->
508 let (name,_,_,_) = List.nth tys typeno in
512 let ty_ty,_ = T.type_of_aux' metasenv context ty CicUniv.empty_ugraph in
516 C.Sort C.Prop -> "_ind"
517 | C.Sort C.Set -> "_rec"
518 | C.Sort C.CProp -> "_rec"
519 | C.Sort (C.Type _)-> "_rect"
522 U.uri_of_string (buri ^ "/" ^ name ^ ext ^ ".con")
524 let eliminator_ref = C.Const (eliminator_uri,exp_named_subst) in
526 T.type_of_aux' metasenv context eliminator_ref CicUniv.empty_ugraph in
527 let rec find_args_no =
529 C.Prod (_,_,t) -> 1 + find_args_no t
530 | C.Cast (s,_) -> find_args_no s
531 | C.LetIn (_,_,t) -> 0 + find_args_no t
534 let args_no = find_args_no ety in
536 let rec make_tl base_case =
539 | n -> (C.Implicit None)::(make_tl base_case (n - 1))
541 C.Appl (eliminator_ref :: make_tl term (args_no - 1))
543 let metasenv', term_to_refine' =
544 CicMkImplicit.expand_implicits metasenv [] context term_to_refine in
545 let refined_term,_,metasenv'',_ = (* TASSI: FIXME *)
546 CicRefine.type_of_aux' metasenv' context term_to_refine'
550 ProofEngineHelpers.compare_metasenvs
551 ~oldmetasenv:metasenv ~newmetasenv:metasenv''
553 let proof' = curi,metasenv'',proofbo,proofty in
554 let proof'', new_goals' =
555 apply_tactic (apply_tac ~term:refined_term) (proof',goal)
557 (* The apply_tactic can have closed some of the new_goals *)
558 let patched_new_goals =
559 let (_,metasenv''',_,_) = proof'' in
561 (function i -> List.exists (function (j,_,_) -> j=i) metasenv'''
562 ) new_goals @ new_goals'
564 proof'', patched_new_goals
566 mk_tactic (elim_tac ~term)
569 let elim_intros_tac ~term =
570 Tacticals.then_ ~start:(elim_tac ~term)
571 ~continuation:(intros_tac ())
574 (* The simplification is performed only on the conclusion *)
575 let elim_intros_simpl_tac ~term =
576 Tacticals.then_ ~start:(elim_tac ~term)
579 ~start:(intros_tac ())
581 [ReductionTactics.simpl_tac ~also_in_hypotheses:false ~terms:None])
584 exception NotConvertible
586 (*CSC: Bug (or feature?). [with_what] is parsed in the context of the goal, *)
587 (*CSC: while [what] can have a richer context (because of binders) *)
588 (*CSC: So it is _NOT_ possible to use those binders in the [with_what] term. *)
589 (*CSC: Is that evident? Is that right? Or should it be changed? *)
590 let change_tac ~what ~with_what =
591 let change_tac ~what ~with_what (proof, goal) =
592 let curi,metasenv,pbo,pty = proof in
593 let metano,context,ty = CicUtil.lookup_meta goal metasenv in
594 (* are_convertible works only on well-typed terms *)
596 CicTypeChecker.type_of_aux' metasenv context with_what
598 in (* TASSI: FIXME *)
600 CicReduction.are_convertible context what with_what u
605 ProofEngineReduction.replace
606 ~equality:(==) ~what:[what] ~with_what:[with_what]
608 let ty' = replace ty in
612 Some (name,Cic.Def (t,None))->
613 Some (name,Cic.Def ((replace t),None))
614 | Some (name,Cic.Decl t) -> Some (name,Cic.Decl (replace t))
616 | Some (_,Cic.Def (_,Some _)) -> assert false
622 (n,_,_) when n = metano -> (metano,context',ty')
626 (curi,metasenv',pbo,pty), [metano]
629 raise (ProofEngineTypes.Fail "Not convertible")
631 mk_tactic (change_tac ~what ~with_what)