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
38 module RT = ReductionTactics
39 module PEH = ProofEngineHelpers
43 if debug then (fun x -> prerr_endline (Lazy.force x)) else (fun _ -> ())
45 (* funzione generale di rilocazione dei riferimenti locali *)
47 let relocate_term map t =
48 let rec map_xnss k xnss =
49 let imap (uri, t) = uri, map_term k t in
54 | Some t -> Some (map_term k t)
58 let imap (name, i, ty, bo) = name, i, map_term k ty, map_term (k + len) bo in
60 and map_cfs len k cfs =
61 let imap (name, ty, bo) = name, map_term k ty, map_term (k + len) bo in
63 and map_term k = function
64 | C.Rel m -> if m < k then C.Rel m else C.Rel (map (m - k))
66 | C.Implicit _ as t -> t
67 | C.Var (uri, xnss) -> C.Var (uri, map_xnss k xnss)
68 | C.Const (uri, xnss) -> C.Const (uri, map_xnss k xnss)
69 | C.MutInd (uri, tyno, xnss) -> C.MutInd (uri, tyno, map_xnss k xnss)
70 | C.MutConstruct (uri, tyno, consno, xnss) ->
71 C.MutConstruct (uri, tyno, consno, map_xnss k xnss)
72 | C.Meta (i, mss) -> C.Meta(i, map_mss k mss)
73 | C.Cast (te, ty) -> C.Cast (map_term k te, map_term k ty)
74 | C.Appl ts -> C.Appl (List.map (map_term k) ts)
75 | C.MutCase (sp, i, outty, t, pl) ->
76 C.MutCase (sp, i, map_term k outty, map_term k t, List.map (map_term k) pl)
77 | C.Prod (n, s, t) -> C.Prod (n, map_term k s, map_term (succ k) t)
78 | C.Lambda (n, s, t) -> C.Lambda (n, map_term k s, map_term (succ k) t)
79 | C.LetIn (n, s, t) -> C.LetIn (n, map_term k s, map_term (succ k) t)
80 | C.Fix (i, fs) -> C.Fix (i, map_fs (List.length fs) k fs)
81 | C.CoFix (i, cfs) -> C.CoFix (i, map_cfs (List.length cfs) k cfs)
87 let after continuation aftermap beforemap =
88 continuation ~map:(fun n -> aftermap (beforemap n))
90 let after2 continuation aftermap beforemap ~map =
91 continuation ~map:(fun n -> map (aftermap (beforemap n)))
93 (* term ha tipo t1=t2; funziona solo se t1 e t2 hanno in testa costruttori
96 let discriminate_tac ~term =
98 match LibraryObjects.true_URI () with
100 | None -> raise (PET.Fail (lazy "You need to register the default \"true\" definition first. Please use the \"default\" command")) in
102 match LibraryObjects.false_URI () with
104 | None -> raise (PET.Fail (lazy "You need to register the default \"false\" definition first. Please use the \"default\" command")) in
105 let fail msg = raise (PET.Fail (lazy ("Discriminate: " ^ msg))) in
106 let find_discriminating_consno t1 t2 =
109 | C.MutConstruct _, C.MutConstruct _ when t1 = t2 -> None
110 | C.Appl ((C.MutConstruct _ as constr1) :: args1),
111 C.Appl ((C.MutConstruct _ as constr2) :: args2)
112 when constr1 = constr2 ->
113 let rec aux_list l1 l2 =
116 | hd1 :: tl1, hd2 :: tl2 ->
117 (match aux hd1 hd2 with
118 | None -> aux_list tl1 tl2
119 | Some _ as res -> res)
120 | _ -> (* same constructor applied to a different number of args *)
124 | ((C.MutConstruct (_,_,consno1,subst1)),
125 (C.MutConstruct (_,_,consno2,subst2)))
126 | ((C.MutConstruct (_,_,consno1,subst1)),
127 (C.Appl ((C.MutConstruct (_,_,consno2,subst2)) :: _)))
128 | ((C.Appl ((C.MutConstruct (_,_,consno1,subst1)) :: _)),
129 (C.MutConstruct (_,_,consno2,subst2)))
130 | ((C.Appl ((C.MutConstruct (_,_,consno1,subst1)) :: _)),
131 (C.Appl ((C.MutConstruct (_,_,consno2,subst2)) :: _)))
132 when (consno1 <> consno2) || (subst1 <> subst2) ->
134 | _ -> fail "not a discriminable equality"
138 let mk_branches_and_outtype turi typeno consno context args =
139 (* a list of "True" except for the element in position consno which
141 match fst (CicEnvironment.get_obj CicUniv.empty_ugraph turi) with
142 | C.InductiveDefinition (ind_type_list,_,paramsno,_) ->
143 let _,_,rty,constructor_list = List.nth ind_type_list typeno in
144 let false_constr_id,_ = List.nth constructor_list (consno - 1) in
148 (* dubbio: e' corretto ridurre in questo context ??? *)
149 let red_ty = CR.whd context cty in
152 | C.Prod (_,_,target) when (k <= paramsno) ->
153 S.subst (List.nth args (k-1))
155 | C.Prod (binder,source,target) when (k > paramsno) ->
156 C.Lambda (binder, source, (aux target (k+1)))
158 if (id = false_constr_id)
159 then (C.MutInd(false_URI,0,[]))
160 else (C.MutInd(true_URI,0,[]))
162 (S.lift 1 (aux red_ty 1)))
166 let rec mk_lambdas rev_left_args =
168 0, args, C.Prod (_,so,ta) ->
170 (C.Name (incr seed; "x" ^ string_of_int !seed),
172 mk_lambdas rev_left_args (0,args,ta))
173 | 0, args, C.Sort _ ->
177 | n -> C.Rel n :: mk_rels (n - 1) in
178 let argsno = List.length args in
181 (if argsno + List.length rev_left_args > 0 then
183 (C.MutInd (turi, typeno, []) ::
185 (S.lift (argsno + 1))
186 (List.rev rev_left_args)) @
189 C.MutInd (turi,typeno,[])),
191 | 0, _, _ -> assert false (* seriously screwed up *)
192 | n, he::tl, C.Prod (_,_,ta) ->
193 mk_lambdas (he::rev_left_args)(n-1,tl,S.subst he ta)
195 assert false (* we should probably reduce in some context *)
197 mk_lambdas [] (paramsno, args, rty)
202 let discriminate'_tac ~term status =
203 let (proof, goal) = status in
204 let _,metasenv,_subst,_,_, _ = proof in
205 let _,context,_ = CicUtil.lookup_meta goal metasenv in
207 CTC.type_of_aux' metasenv context term CicUniv.empty_ugraph
210 | C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2]
211 when LibraryObjects.is_eq_URI equri ->
212 let turi,typeno,exp_named_subst,args =
214 | (C.MutInd (turi,typeno,exp_named_subst)) ->
215 turi,typeno,exp_named_subst,[]
216 | (C.Appl (C.MutInd (turi,typeno,exp_named_subst)::args)) ->
217 turi,typeno,exp_named_subst,args
218 | _ -> fail "not a discriminable equality"
221 match find_discriminating_consno t1 t2 with
222 | Some consno -> consno
223 | None -> fail "discriminating terms are structurally equal"
225 let branches,outtype =
226 mk_branches_and_outtype turi typeno consno context args
230 ~start:(EliminationTactics.elim_type_tac (C.MutInd (false_URI, 0, [])))
235 ~pattern:(PET.conclusion_pattern None)
238 C.Lambda ( C.Name "x", tty,
239 C.MutCase (turi, typeno, outtype, (C.Rel 1), branches));
245 (EqualityTactics.rewrite_simpl_tac
246 ~direction:`RightToLeft
247 ~pattern:(PET.conclusion_pattern None)
250 (IntroductionTactics.constructor_tac ~n:1)))) status
251 | _ -> fail "not an equality"
253 PET.mk_tactic (discriminate'_tac ~term)
256 PET.Fail (lazy "Injection: not a projectable equality")
258 PET.Fail (lazy "Injection: not an equality")
259 let exn_nothingtodo =
260 PET.Fail (lazy "Nothing to do")
261 let exn_discrnonind =
262 PET.Fail (lazy "Discriminate: object is not an Inductive Definition: it's imposible")
263 let exn_injwronggoal =
264 PET.Fail (lazy "Injection: goal after cut is not correct")
266 PET.Fail (lazy "Injection: not an equality over elements of an inductive type")
269 let names = List.map (function Some (n,_) -> Some n | None -> None) ctx in
272 let clear_term first_time context term =
273 let g () = if first_time then raise exn_nothingtodo else T.id_tac in
276 begin match List.nth context (pred n) with
277 | Some (C.Name id, _) -> PST.clear ~hyps:[id]
282 let simpl_in_term context = function
284 let name = match List.nth context (pred i) with
285 | Some (Cic.Name s, Cic.Def _) -> s
286 | Some (Cic.Name s, Cic.Decl _) -> s
289 RT.simpl_tac ~pattern:(None,[name,Cic.Implicit (Some `Hole)],None)
290 | _ -> raise exn_nonproj
292 (* ~term vive nel contesto della tattica una volta ~mappato
293 * ~continuation riceve la mappa assoluta
295 let rec injection_tac ~map ~term ~i ~continuation =
296 let give_name seed = function
297 | C.Name _ as name -> name
298 | C.Anonymous -> C.Name (incr seed; "y" ^ string_of_int !seed)
300 let rec mk_rels = function | 0 -> [] | n -> C.Rel n :: (mk_rels (n - 1)) in
301 let injection_tac status =
302 let (proof, goal) = status in
303 (* precondizione: t1 e t2 hanno in testa lo stesso costruttore ma
304 * differiscono (o potrebbero differire?) nell'i-esimo parametro
306 let _,metasenv,_subst,_,_, _ = proof in
307 let _,context,_ = CicUtil.lookup_meta goal metasenv in
308 let term = relocate_term map term in
310 CTC.type_of_aux' metasenv context term CicUniv.empty_ugraph
312 debug_print (lazy ("\ninjection su : " ^ pp context termty));
313 match termty with (* an equality *)
314 | C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2]
315 when LibraryObjects.is_eq_URI equri ->
316 let turi,typeno,ens,params =
317 match tty with (* some inductive type *)
318 | C.MutInd (turi,typeno,ens) -> turi,typeno,ens,[]
319 | C.Appl (C.MutInd (turi,typeno,ens)::params) -> turi,typeno,ens,params
320 | _ -> raise exn_noneqind
322 let t1',t2',consno = (* sono i due sottotermini che differiscono *)
324 | C.Appl ((C.MutConstruct (uri1,typeno1,consno1,ens1))::applist1),
325 C.Appl ((C.MutConstruct (uri2,typeno2,consno2,ens2))::applist2)
326 when (uri1 = uri2) && (typeno1 = typeno2) &&
327 (consno1 = consno2) && (ens1 = ens2) ->
328 (* controllo ridondante *)
329 List.nth applist1 (pred i),List.nth applist2 (pred i),consno2
332 let tty',_ = CTC.type_of_aux' metasenv context t1' CU.empty_ugraph in
333 let patterns,outtype =
334 match fst (CicEnvironment.get_obj CicUniv.empty_ugraph turi) with
335 | C.InductiveDefinition (ind_type_list,_,paramsno,_)->
336 let left_params, right_params = HExtlib.split_nth paramsno params in
337 let _,_,_,constructor_list = List.nth ind_type_list typeno in
338 let i_constr_id,_ = List.nth constructor_list (consno - 1) in
342 (function (id,cty) ->
343 let reduced_cty = CR.whd context cty in
344 let rec aux k = function
345 | C.Prod (_,_,tgt) when k <= paramsno ->
346 let left = List.nth left_params (k-1) in
347 aux (k+1) (S.subst left tgt)
348 | C.Prod (binder,source,target) when k > paramsno ->
349 let binder' = give_name seed binder in
350 C.Lambda (binder',source,(aux (k+1) target))
352 let nr_param_constr = k - paramsno - 1 in
353 if id = i_constr_id then C.Rel (k - i)
354 else S.lift nr_param_constr t1'
355 (* + 1 per liftare anche il lambda aggiunto
356 * esternamente al case *)
357 in S.lift 1 (aux 1 reduced_cty))
360 (* this code should be taken from cases_tac *)
363 let rec to_lambdas te head =
364 match CR.whd context te with
365 | C.Prod (binder,so,ta) ->
366 let binder' = give_name seed binder in
367 C.Lambda (binder',so,to_lambdas ta head)
370 let rec skip_prods params te =
371 match params, CR.whd context te with
373 | left::tl, C.Prod (_,_,ta) ->
374 skip_prods tl (S.subst left ta)
375 | _, _ -> assert false
379 List.fold_left (fun x y -> S.subst y x) tty left_params
381 (* non lift, ma subst coi left! *)
382 match S.lift 1 tty with
383 | C.MutInd _ as tty' -> tty'
385 let keep,abstract = HExtlib.split_nth (paramsno +1) l in
386 let keep = List.map (S.lift paramsno) keep in
387 C.Appl (keep@mk_rels (List.length abstract))
390 match ind_type_list with
393 (* this is in general wrong, do as in cases_tac *)
394 to_lambdas (skip_prods left_params ty)
396 (C.Name "cased", abstracted_tty,
397 (* here we should capture right parameters *)
398 (* 1 for his Lambda, one for the Lambda outside the match
399 * and then one for each to_lambda *)
400 S.lift (2+List.length right_params) tty'))
403 | _ -> raise exn_discrnonind
405 let cutted = C.Appl [C.MutInd (equri,0,[]) ; tty' ; t1' ; t2'] in
407 C.Appl [ C.Lambda (C.Name "x", tty,
408 C.MutCase (turi,typeno,outtype,C.Rel 1,patterns)) ; t1]
410 (* check if cutted and changed are well typed and if t1' ~ changed *)
413 let _,g = CTC.type_of_aux' metasenv context cutted
416 let _,g = CTC.type_of_aux' metasenv context changed g in
417 fst (CR.are_convertible ~metasenv context t1' changed g)
419 | CTC.TypeCheckerFailure _ -> false
422 PET.apply_tactic T.id_tac status (* FG: ??????? *)
426 debug_print (lazy "riempio il cut");
427 let (proof, goal) = status in
428 let _,metasenv,_subst,_,_, _ = proof in
429 let _,context,gty = CicUtil.lookup_meta goal metasenv in
430 let gty = Unshare.unshare gty in
431 let new_t1' = match gty with
432 | (C.Appl (C.MutInd (_,_,_)::_::t::_)) -> t
433 | _ -> raise exn_injwronggoal
435 debug_print (lazy ("metto: " ^ pp context changed));
436 debug_print (lazy ("al posto di: " ^ pp context new_t1'));
437 debug_print (lazy ("nel goal: " ^ pp context gty));
438 debug_print (lazy ("nel contesto:\n" ^ CicPp.ppcontext context));
439 debug_print (lazy ("e poi rewrite con: "^pp context term));
440 let tac = T.seq ~tactics:[
442 ~pattern:(None, [], Some (PEH.pattern_of ~term:gty [new_t1']))
443 (fun _ m u -> changed,m,u);
444 EqualityTactics.rewrite_simpl_tac
445 ~direction:`LeftToRight
446 ~pattern:(PET.conclusion_pattern None)
448 EqualityTactics.reflexivity_tac
450 PET.apply_tactic tac status
454 debug_print (lazy ("CUT: " ^ pp context cutted));
456 (T.thens ~start: (P.cut_tac cutted)
458 (qnify_tac ~first_time:false ~term:(C.Rel 1) ~map:id
459 ~continuation:(after2 continuation succ map)
463 | _ -> raise exn_noneq
465 PET.mk_tactic injection_tac
467 (* ~term vive nel contesto della tattica una volta ~mappato
468 * ~continuation riceve la mappa assoluta
470 and qnify_tac ~first_time ~map ~term ~continuation =
471 let are_convertible hd1 hd2 metasenv context =
472 fst (CR.are_convertible ~metasenv context hd1 hd2 CicUniv.empty_ugraph)
474 let qnify_tac status =
475 let (proof, goal) = status in
476 let _,metasenv,_subst, _,_, _ = proof in
477 let _,context,_ = CicUtil.lookup_meta goal metasenv in
478 let term = relocate_term map term in
479 debug_print (lazy ("\nqnify di: " ^ pp context term));
480 debug_print (lazy ("nel contesto:\n" ^ CicPp.ppcontext context));
482 CTC.type_of_aux' metasenv context term CicUniv.empty_ugraph
484 debug_print (lazy ("\nqnify su: " ^ pp context termty));
485 let tac = match termty with
486 | C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2]
487 when LibraryObjects.is_eq_URI equri -> begin
488 match (CR.whd ~delta:true context tty) with
490 | C.Appl (C.MutInd _ :: _) ->
491 begin match t1,t2 with
495 T.then_ ~start:(clear_term first_time context term)
496 ~continuation:(continuation ~map)
497 | C.Appl (C.MutConstruct _ as mc1 :: applist1),
498 C.Appl (C.MutConstruct _ as mc2 :: applist2)
500 let rec traverse_list first_time i l1 l2 =
504 T.then_ ~start:(clear_term first_time context term)
505 ~continuation:(after continuation aftermap map)
506 | hd1 :: tl1, hd2 :: tl2 ->
507 if are_convertible hd1 hd2 metasenv context then
508 traverse_list first_time (succ i) tl1 tl2
510 injection_tac ~i ~term ~continuation:
511 (traverse_list false (succ i) tl1 tl2)
513 (* i 2 termini hanno in testa lo stesso costruttore,
514 * ma applicato a un numero diverso di termini *)
516 traverse_list first_time 1 applist1 applist2 ~map:id
517 | C.MutConstruct (_,_,consno1,ens1),
518 C.MutConstruct (_,_,consno2,ens2)
519 | C.MutConstruct (_,_,consno1,ens1),
520 C.Appl ((C.MutConstruct (_,_,consno2,ens2))::_)
521 | C.Appl ((C.MutConstruct (_,_,consno1,ens1))::_),
522 C.MutConstruct (_,_,consno2,ens2)
523 | C.Appl ((C.MutConstruct (_,_,consno1,ens1))::_),
524 C.Appl ((C.MutConstruct (_,_,consno2,ens2))::_)
525 when (consno1 <> consno2) || (ens1 <> ens2) ->
526 discriminate_tac ~term
527 | _ when not first_time -> continuation ~map
528 | _ (* when first_time *) ->
529 T.then_ ~start:(simpl_in_term context term)
530 ~continuation:(qnify_tac ~first_time:false ~term ~map ~continuation)
532 | _ when not first_time -> continuation ~map
533 | _ (* when first_time *) -> raise exn_nonproj
535 | _ -> raise exn_nonproj
537 PET.apply_tactic tac status
539 PET.mk_tactic qnify_tac
541 (* destruct performs either injection or discriminate *)
542 (* equivalent to Coq's "analyze equality" *)
545 ~first_time:true ~map:id ~continuation:(fun ~map -> T.id_tac)