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.
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23 * http://cs.unibo.it/helm/.
30 module P = PrimitiveTactics
32 module CR = CicReduction
33 module PST = ProofEngineStructuralRules
34 module PET = ProofEngineTypes
35 module CTC = CicTypeChecker
37 module S = CicSubstitution
41 if debug then (fun x -> prerr_endline (Lazy.force x)) else (fun _ -> ())
44 (* funzione generale di rilocazione dei riferimenti locali *)
46 let relocate_term map t =
47 let rec map_xnss k xnss =
48 let imap (uri, t) = uri, map_term k t in
53 | Some t -> Some (map_term k t)
57 let imap (name, i, ty, bo) = name, i, map_term k ty, map_term (k + len) bo in
59 and map_cfs len k cfs =
60 let imap (name, ty, bo) = name, map_term k ty, map_term (k + len) bo in
62 and map_term k = function
63 | C.Rel m -> if m < k then C.Rel m else C.Rel (map (m - k))
65 | C.Implicit _ as t -> t
66 | C.Var (uri, xnss) -> C.Var (uri, map_xnss k xnss)
67 | C.Const (uri, xnss) -> C.Const (uri, map_xnss k xnss)
68 | C.MutInd (uri, tyno, xnss) -> C.MutInd (uri, tyno, map_xnss k xnss)
69 | C.MutConstruct (uri, tyno, consno, xnss) ->
70 C.MutConstruct (uri, tyno, consno, map_xnss k xnss)
71 | C.Meta (i, mss) -> C.Meta(i, map_mss k mss)
72 | C.Cast (te, ty) -> C.Cast (map_term k te, map_term k ty)
73 | C.Appl ts -> C.Appl (List.map (map_term k) ts)
74 | C.MutCase (sp, i, outty, t, pl) ->
75 C.MutCase (sp, i, map_term k outty, map_term k t, List.map (map_term k) pl)
76 | C.Prod (n, s, t) -> C.Prod (n, map_term k s, map_term (succ k) t)
77 | C.Lambda (n, s, t) -> C.Lambda (n, map_term k s, map_term (succ k) t)
78 | C.LetIn (n, s, t) -> C.LetIn (n, map_term k s, map_term (succ k) t)
79 | C.Fix (i, fs) -> C.Fix (i, map_fs (List.length fs) k fs)
80 | C.CoFix (i, cfs) -> C.CoFix (i, map_cfs (List.length cfs) k cfs)
84 (* term ha tipo t1=t2; funziona solo se t1 e t2 hanno in testa costruttori
87 let discriminate_tac ~term =
89 match LibraryObjects.true_URI () with
91 | None -> raise (PET.Fail (lazy "You need to register the default \"true\" definition first. Please use the \"default\" command")) in
93 match LibraryObjects.false_URI () with
95 | None -> raise (PET.Fail (lazy "You need to register the default \"false\" definition first. Please use the \"default\" command")) in
96 let fail msg = raise (PET.Fail (lazy ("Discriminate: " ^ msg))) in
97 let find_discriminating_consno t1 t2 =
100 | C.MutConstruct _, C.MutConstruct _ when t1 = t2 -> None
101 | C.Appl ((C.MutConstruct _ as constr1) :: args1),
102 C.Appl ((C.MutConstruct _ as constr2) :: args2)
103 when constr1 = constr2 ->
104 let rec aux_list l1 l2 =
107 | hd1 :: tl1, hd2 :: tl2 ->
108 (match aux hd1 hd2 with
109 | None -> aux_list tl1 tl2
110 | Some _ as res -> res)
111 | _ -> (* same constructor applied to a different number of args *)
115 | ((C.MutConstruct (_,_,consno1,subst1)),
116 (C.MutConstruct (_,_,consno2,subst2)))
117 | ((C.MutConstruct (_,_,consno1,subst1)),
118 (C.Appl ((C.MutConstruct (_,_,consno2,subst2)) :: _)))
119 | ((C.Appl ((C.MutConstruct (_,_,consno1,subst1)) :: _)),
120 (C.MutConstruct (_,_,consno2,subst2)))
121 | ((C.Appl ((C.MutConstruct (_,_,consno1,subst1)) :: _)),
122 (C.Appl ((C.MutConstruct (_,_,consno2,subst2)) :: _)))
123 when (consno1 <> consno2) || (subst1 <> subst2) ->
125 | _ -> fail "not a discriminable equality"
129 let mk_branches_and_outtype turi typeno consno context args =
130 (* a list of "True" except for the element in position consno which
132 match fst (CicEnvironment.get_obj CicUniv.empty_ugraph turi) with
133 | C.InductiveDefinition (ind_type_list,_,paramsno,_) ->
134 let _,_,rty,constructor_list = List.nth ind_type_list typeno in
135 let false_constr_id,_ = List.nth constructor_list (consno - 1) in
139 (* dubbio: e' corretto ridurre in questo context ??? *)
140 let red_ty = CR.whd context cty in
143 | C.Prod (_,_,target) when (k <= paramsno) ->
144 S.subst (List.nth args (k-1))
146 | C.Prod (binder,source,target) when (k > paramsno) ->
147 C.Lambda (binder, source, (aux target (k+1)))
149 if (id = false_constr_id)
150 then (C.MutInd(false_URI,0,[]))
151 else (C.MutInd(true_URI,0,[]))
153 (S.lift 1 (aux red_ty 1)))
157 let rec mk_lambdas rev_left_args =
159 0, args, C.Prod (_,so,ta) ->
161 (C.Name (incr seed; "x" ^ string_of_int !seed),
163 mk_lambdas rev_left_args (0,args,ta))
164 | 0, args, C.Sort _ ->
168 | n -> C.Rel n :: mk_rels (n - 1) in
169 let argsno = List.length args in
172 (if argsno + List.length rev_left_args > 0 then
174 (C.MutInd (turi, typeno, []) ::
176 (S.lift (argsno + 1))
177 (List.rev rev_left_args)) @
180 C.MutInd (turi,typeno,[])),
182 | 0, _, _ -> assert false (* seriously screwed up *)
183 | n, he::tl, C.Prod (_,_,ta) ->
184 mk_lambdas (he::rev_left_args)(n-1,tl,S.subst he ta)
186 assert false (* we should probably reduce in some context *)
188 mk_lambdas [] (paramsno, args, rty)
193 let discriminate'_tac ~term status =
194 let (proof, goal) = status in
195 let _,metasenv,_subst,_,_, _ = proof in
196 let _,context,_ = CicUtil.lookup_meta goal metasenv in
198 CTC.type_of_aux' metasenv context term CicUniv.empty_ugraph
201 | C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2]
202 when LibraryObjects.is_eq_URI equri ->
203 let turi,typeno,exp_named_subst,args =
205 | (C.MutInd (turi,typeno,exp_named_subst)) ->
206 turi,typeno,exp_named_subst,[]
207 | (C.Appl (C.MutInd (turi,typeno,exp_named_subst)::args)) ->
208 turi,typeno,exp_named_subst,args
209 | _ -> fail "not a discriminable equality"
212 match find_discriminating_consno t1 t2 with
213 | Some consno -> consno
214 | None -> fail "discriminating terms are structurally equal"
216 let branches,outtype =
217 mk_branches_and_outtype turi typeno consno context args
221 ~start:(EliminationTactics.elim_type_tac (C.MutInd (false_URI, 0, [])))
225 (ReductionTactics.change_tac
226 ~pattern:(PET.conclusion_pattern None)
229 C.Lambda ( C.Name "x", tty,
230 C.MutCase (turi, typeno, outtype, (C.Rel 1), branches));
236 (EqualityTactics.rewrite_simpl_tac
237 ~direction:`RightToLeft
238 ~pattern:(PET.conclusion_pattern None)
241 (IntroductionTactics.constructor_tac ~n:1)))) status
242 | _ -> fail "not an equality"
244 PET.mk_tactic (discriminate'_tac ~term)
247 PET.Fail (lazy "Injection: not a projectable equality")
249 PET.Fail (lazy "Injection: not an equality")
250 let exn_nothingtodo =
251 PET.Fail (lazy "Nothing to do")
252 let exn_discrnonind =
253 PET.Fail (lazy "Discriminate: object is not an Inductive Definition: it's imposible")
254 let exn_injwronggoal =
255 PET.Fail (lazy "Injection: goal after cut is not correct")
257 PET.Fail (lazy "Injection: not an equality over elements of an inductive type")
260 let names = List.map (function Some (n,_) -> Some n | None -> None) ctx in
263 let rec injection_tac ~term ~i ~liftno ~continuation =
264 let give_name seed = function
265 | C.Name _ as name -> name
266 | C.Anonymous -> C.Name (incr seed; "y" ^ string_of_int !seed)
268 let rec mk_rels = function | 0 -> [] | n -> C.Rel n :: (mk_rels (n - 1)) in
269 let injection_tac ~term ~i status =
270 let (proof, goal) = status in
271 (* precondizione: t1 e t2 hanno in testa lo stesso costruttore ma
272 * differiscono (o potrebbero differire?) nell'i-esimo parametro
274 let term = S.lift liftno term in
275 let _,metasenv,_subst,_,_, _ = proof in
276 let _,context,_ = CicUtil.lookup_meta goal metasenv in
278 CTC.type_of_aux' metasenv context term CicUniv.empty_ugraph
280 debug_print (lazy ("\ninjection1 su : " ^ pp context termty));
281 match termty with (* an equality *)
282 | C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2]
283 when LibraryObjects.is_eq_URI equri ->
284 let turi,typeno,ens,params =
285 match tty with (* some inductive type *)
286 | C.MutInd (turi,typeno,ens) -> turi,typeno,ens,[]
287 | C.Appl (C.MutInd (turi,typeno,ens)::params) -> turi,typeno,ens,params
288 | _ -> raise exn_noneqind
290 let t1',t2',consno = (* sono i due sottotermini che differiscono *)
292 | C.Appl ((C.MutConstruct (uri1,typeno1,consno1,ens1))::applist1),
293 C.Appl ((C.MutConstruct (uri2,typeno2,consno2,ens2))::applist2)
294 when (uri1 = uri2) && (typeno1 = typeno2) &&
295 (consno1 = consno2) && (ens1 = ens2) ->
296 (* controllo ridondante *)
297 List.nth applist1 (i-1),List.nth applist2 (i-1),consno2
300 let tty',_ = CTC.type_of_aux' metasenv context t1' CU.empty_ugraph in
301 let patterns,outtype =
302 match fst (CicEnvironment.get_obj CicUniv.empty_ugraph turi) with
303 | C.InductiveDefinition (ind_type_list,_,paramsno,_)->
304 let left_params, right_params = HExtlib.split_nth paramsno params in
305 let _,_,_,constructor_list = List.nth ind_type_list typeno in
306 let i_constr_id,_ = List.nth constructor_list (consno - 1) in
310 (function (id,cty) ->
311 let reduced_cty = CR.whd context cty in
312 let rec aux k = function
313 | C.Prod (_,_,tgt) when k <= paramsno ->
314 let left = List.nth left_params (k-1) in
315 aux (k+1) (S.subst left tgt)
316 | C.Prod (binder,source,target) when k > paramsno ->
317 let binder' = give_name seed binder in
318 C.Lambda (binder',source,(aux (k+1) target))
320 let nr_param_constr = k - paramsno - 1 in
321 if id = i_constr_id then C.Rel (k - i)
322 else S.lift nr_param_constr t1'
323 (* + 1 per liftare anche il lambda aggiunto
324 * esternamente al case *)
325 in S.lift 1 (aux 1 reduced_cty))
328 (* this code should be taken from cases_tac *)
331 let rec to_lambdas te head =
332 match CR.whd context te with
333 | C.Prod (binder,so,ta) ->
334 let binder' = give_name seed binder in
335 C.Lambda (binder',so,to_lambdas ta head)
338 let rec skip_prods params te =
339 match params, CR.whd context te with
341 | left::tl, C.Prod (_,_,ta) ->
342 skip_prods tl (S.subst left ta)
343 | _, _ -> assert false
347 List.fold_left (fun x y -> S.subst y x) tty left_params
349 (* non lift, ma subst coi left! *)
350 match S.lift 1 tty with
351 | C.MutInd _ as tty' -> tty'
353 let keep,abstract = HExtlib.split_nth (paramsno +1) l in
354 let keep = List.map (S.lift paramsno) keep in
355 C.Appl (keep@mk_rels (List.length abstract))
358 match ind_type_list with
361 (* this is in general wrong, do as in cases_tac *)
362 to_lambdas (skip_prods left_params ty)
364 (C.Name "cased", abstracted_tty,
365 (* here we should capture right parameters *)
366 (* 1 for his Lambda, one for the Lambda outside the match
367 * and then one for each to_lambda *)
368 S.lift (2+List.length right_params) tty'))
371 | _ -> raise exn_discrnonind
373 let cutted = C.Appl [C.MutInd (equri,0,[]) ; tty' ; t1' ; t2'] in
375 C.Appl [ C.Lambda (C.Name "x", tty,
376 C.MutCase (turi,typeno,outtype,C.Rel 1,patterns)) ; t1]
378 (* check if cutted and changed are well typed and if t1' ~ changed *)
381 let _,g = CTC.type_of_aux' metasenv context cutted
384 let _,g = CTC.type_of_aux' metasenv context changed g in
385 fst (CR.are_convertible ~metasenv context t1' changed g)
387 | CTC.TypeCheckerFailure _ -> false
390 PET.apply_tactic T.id_tac status
392 (debug_print (lazy ("CUT: " ^ pp context cutted));
394 (T.thens ~start: (P.cut_tac cutted)
396 [injection1_tac ~first_time:false ~liftno:0 ~term:(C.Rel 1)
398 (fun ~liftno:x -> continuation ~liftno:(liftno+1+x))
399 (* here I need to lift all the continuations by 1;
400 since I am setting back liftno to 0, I actually
401 need to lift all the continuations by liftno + 1 *)
403 ~start:(PET.mk_tactic
405 debug_print (lazy "riempo il cut");
406 let (proof, goal) = status in
407 let _,metasenv,_subst,_,_, _ = proof in
408 let _,context,gty =CicUtil.lookup_meta goal metasenv in
409 let gty = Unshare.unshare gty in
412 | (C.Appl (C.MutInd (_,_,_)::_::t::_)) -> t
413 | _ -> raise exn_injwronggoal
416 (lazy ("metto questo: " ^ pp context changed));
418 (lazy ("al posto di questo: " ^ pp context new_t1'));
420 (lazy ("nel goal: " ^ pp context gty));
422 (lazy ("nel contesto:\n" ^ CicPp.ppcontext context));
424 (lazy ("e poi rewrite con: "^pp context term));
427 (ReductionTactics.change_tac
429 Some (ProofEngineHelpers.pattern_of
430 ~term:gty [new_t1']))
431 (fun _ m u -> changed,m,u))
438 (EqualityTactics.rewrite_simpl_tac
439 ~direction:`LeftToRight
440 ~pattern:(PET.conclusion_pattern None)
442 ~continuation:EqualityTactics.reflexivity_tac)
445 | _ -> raise exn_noneq
447 PET.mk_tactic (injection_tac ~term ~i)
449 and injection1_tac ~first_time ~term ~liftno ~continuation =
450 let are_convertible hd1 hd2 metasenv context =
451 fst (CR.are_convertible ~metasenv context hd1 hd2 CicUniv.empty_ugraph)
453 let injection1_tac ~term status =
454 let (proof, goal) = status in
455 let _,metasenv,_subst, _,_, _ = proof in
456 let _,context,_ = CicUtil.lookup_meta goal metasenv in
457 let term = S.lift liftno term in
459 CTC.type_of_aux' metasenv context term CicUniv.empty_ugraph
461 debug_print (lazy ("\ninjection su: " ^ pp context termty));
464 | C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2]
465 when LibraryObjects.is_eq_URI equri -> begin
466 match (CR.whd ~delta:true context tty) with
467 | C.MutInd (turi,typeno,ens)
468 | C.Appl (C.MutInd (turi,typeno,ens)::_) -> begin
470 | C.MutConstruct (uri1,typeno1,consno1,ens1),
471 C.MutConstruct (uri2,typeno2,consno2,ens2)
472 when (uri1 = uri2) && (typeno1 = typeno2) &&
473 (consno1 = consno2) && (ens1 = ens2) ->
474 if first_time then raise exn_nothingtodo
475 else continuation ~liftno
476 | C.Appl ((C.MutConstruct (uri1,typeno1,consno1,ens1))::applist1),
477 C.Appl ((C.MutConstruct (uri2,typeno2,consno2,ens2))::applist2)
478 when (uri1 = uri2) && (typeno1 = typeno2) &&
479 (consno1 = consno2) && (ens1 = ens2) ->
480 let rec traverse_list i l1 l2 =
482 | [],[] when first_time -> continuation
486 match List.nth context (n-1) with
487 | Some (C.Name id,_) ->
489 T.then_ ~start:(PST.clear ~hyps:[id])
490 ~continuation:(continuation ~liftno)
495 | hd1::tl1,hd2::tl2 ->
496 if are_convertible hd1 hd2 metasenv context then
497 traverse_list (i+1) tl1 tl2
499 injection_tac ~i ~term
500 ~continuation:(traverse_list (i+1) tl1 tl2)
502 (* i 2 termini hanno in testa lo stesso costruttore,
503 * ma applicato a un numero diverso di termini *)
505 traverse_list 1 applist1 applist2 ~liftno
506 | C.MutConstruct (uri1,typeno1,consno1,ens1),
507 C.MutConstruct (uri2,typeno2,consno2,ens2)
508 | C.MutConstruct (uri1,typeno1,consno1,ens1),
509 C.Appl ((C.MutConstruct (uri2,typeno2,consno2,ens2))::_)
510 | C.Appl ((C.MutConstruct (uri1,typeno1,consno1,ens1))::_),
511 C.MutConstruct (uri2,typeno2,consno2,ens2)
512 | C.Appl ((C.MutConstruct (uri1,typeno1,consno1,ens1))::_),
513 C.Appl ((C.MutConstruct (uri2,typeno2,consno2,ens2))::_)
514 when (consno1 <> consno2) || (ens1 <> ens2) ->
515 discriminate_tac ~term
516 | _ when not first_time -> continuation ~liftno
517 | _ (* when first_time *) ->
521 match List.nth context (i-1) with
522 | Some (Cic.Name s, Cic.Def _) -> s
523 | Some (Cic.Name s, Cic.Decl _) -> s
527 ~start:(ReductionTactics.simpl_tac
528 ~pattern:(None,[name,Cic.Implicit (Some `Hole)],None))
529 ~continuation:(injection1_tac ~first_time:false ~term ~liftno
531 | _ -> raise exn_nonproj
533 | _ when not first_time -> continuation ~liftno
534 | _ (* when first_time *) -> raise exn_nonproj
536 | _ -> raise exn_nonproj
538 PET.apply_tactic tac status
540 PET.mk_tactic (injection1_tac ~term)
542 (* destruct performs either injection or discriminate *)
543 (* equivalent to Coq's "analyze equality" *)
546 ~first_time:true ~liftno:0 ~continuation:(fun ~liftno -> T.id_tac)