2 ||M|| This file is part of HELM, an Hypertextual, Electronic
3 ||A|| Library of Mathematics, developed at the Computer Science
4 ||T|| Department, University of Bologna, Italy.
6 ||T|| HELM is free software; you can redistribute it and/or
7 ||A|| modify it under the terms of the GNU General Public License
8 \ / version 2 or (at your option) any later version.
9 \ / This software is distributed as is, NO WARRANTY.
10 V_______________________________________________________________ *)
14 exception UnificationFailure of string Lazy.t;;
15 exception Uncertain of string Lazy.t;;
16 exception AssertFailure of string Lazy.t;;
18 let (===) x y = Pervasives.compare x y = 0 ;;
20 let uncert_exc metasenv subst context t1 t2 =
22 "Can't unify " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^
23 " with " ^ NCicPp.ppterm ~metasenv ~subst ~context t2))
26 let fail_exc metasenv subst context t1 t2 =
27 UnificationFailure (lazy (
28 "Can't unify " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^
29 " with " ^ NCicPp.ppterm ~metasenv ~subst ~context t2));
32 let mk_appl ~upto hd tl =
33 NCicReduction.head_beta_reduce ~upto
35 | NCic.Appl l -> NCic.Appl (l@tl)
36 | _ -> NCic.Appl (hd :: tl))
39 exception WrongShape;;
41 let eta_reduce subst t =
42 let delift_if_not_occur body =
44 Some (NCicSubstitution.psubst ~avoid_beta_redexes:true
45 (fun () -> raise WrongShape) [()] body)
46 with WrongShape -> None
48 let rec eat_lambdas ctx = function
49 | NCic.Lambda (name, src, tgt) ->
50 eat_lambdas ((name, src) :: ctx) tgt
51 | NCic.Meta (i,lc) as t->
53 let _,_,t,_ = NCicUtils.lookup_subst i subst in
54 let t = NCicSubstitution.subst_meta lc t in
56 with Not_found -> ctx, t)
59 let context_body = eat_lambdas [] t in
60 let rec aux = function
62 | (name, src)::ctx, (NCic.Appl (hd::[NCic.Rel 1]) as bo) ->
63 (match delift_if_not_occur hd with
64 | None -> aux (ctx,NCic.Lambda(name,src, bo))
65 | Some bo -> aux (ctx,bo))
66 | (name, src)::ctx, (NCic.Appl args as bo)
67 when HExtlib.list_last args = NCic.Rel 1 ->
68 let args, _ = HExtlib.split_nth (List.length args - 1) args in
69 (match delift_if_not_occur (NCic.Appl args) with
70 | None -> aux (ctx,NCic.Lambda(name,src, bo))
71 | Some bo -> aux (ctx,bo))
72 | (name, src) :: ctx, t ->
73 aux (ctx,NCic.Lambda(name,src, t))
79 module Ref = NReference;;
85 fun s -> prerr_endline (Printf.sprintf "%-20s" !indent ^ " " ^ Lazy.force s)
90 indent := !indent ^ String.make 1 c;
91 if debug then prerr_endline ("{{{" ^ !indent ^ " ")
94 if debug then prerr_endline "}}}";
95 if not ok then pp (lazy "exception raised!");
97 indent := String.sub !indent 0 (String.length !indent -1)
99 Invalid_argument _ -> indent := "??"; ()
102 let ppcontext ~metasenv ~subst c =
103 "\nctx:\n"^ NCicPp.ppcontext ~metasenv ~subst c
105 let ppmetasenv ~subst m = "\nmenv:\n" ^ NCicPp.ppmetasenv ~subst m;;
107 let ppcontext ~metasenv:_metasenv ~subst:_subst _context = "";;
108 let ppmetasenv ~subst:_subst _metasenv = "";;
110 let fix_sorts swap exc t =
111 let rec aux () = function
112 | NCic.Sort (NCic.Type u) as orig ->
114 match NCicEnvironment.sup u with
116 prerr_endline ("no sup for " ^ NCicPp.ppterm ~metasenv:[] ~subst:[] ~context:[] orig) ;
118 | Some u1 -> if u = u1 then orig else NCic.Sort (NCic.Type u1)
120 NCic.Sort (NCic.Type (
121 match NCicEnvironment.sup NCicEnvironment.type0 with
123 | _ -> assert false))
124 | NCic.Meta _ as orig -> orig
125 | t -> NCicUtils.map (fun _ _ -> ()) () aux t
130 let is_locked n subst =
132 match NCicUtils.lookup_subst n subst with
133 | tag, _,_,_ when NCicMetaSubst.is_out_scope_tag tag -> true
135 with NCicUtils.Subst_not_found _ -> false
141 | n -> NCic.Rel n :: mk_irl (n-1)
144 (* the argument must be a term in whd *)
145 let rec could_reduce =
148 | C.Appl (C.Const (Ref.Ref (_,Ref.Fix (_,recno,_)))::args)
149 when List.length args > recno -> could_reduce (List.nth args recno)
150 | C.Match (_,_,arg,_) -> could_reduce arg
151 | C.Appl (he::_) -> could_reduce he
152 | C.Sort _ | C.Rel _ | C.Prod _ | C.Lambda _ | C.Const _ -> false
153 | C.Appl [] | C.LetIn _ | C.Implicit _ -> assert false
156 let rec lambda_intros rdb metasenv subst context t args =
157 let tty = NCicTypeChecker.typeof ~metasenv ~subst context t in
160 (fun arg -> arg, NCicTypeChecker.typeof ~metasenv ~subst context arg) args in
161 let context_of_args = context in
162 let rec mk_lambda metasenv subst context n processed_args = function
164 let metasenv, _, bo, _ =
165 NCicMetaSubst.mk_meta metasenv context
166 (`WithType (NCicSubstitution.lift n tty))
171 NCicPp.ppterm ~metasenv ~subst ~context:context_of_args arg ^ ":" ^
172 NCicPp.ppterm ~metasenv ~subst ~context:context_of_args ty));
173 let metasenv, subst, telescopic_ty =
174 if processed_args = [] then metasenv, subst, ty else
175 let _ = pp(lazy("delift")) in
176 delift_type_wrt_terms rdb metasenv subst context_of_args ty
177 (List.rev processed_args)
180 let name = "HBeta"^string_of_int n in
181 let metasenv, subst, bo =
182 mk_lambda metasenv subst ((name,NCic.Decl telescopic_ty)::context) (n+1)
183 (arg::processed_args) tail
185 metasenv, subst, NCic.Lambda (name, telescopic_ty, bo)
187 pp(lazy("LAMBDA_INTROS{ " ^
188 NCicPp.ppterm ~metasenv ~subst ~context t ^ ":" ^
189 NCicPp.ppterm ~metasenv ~subst ~context tty ^ " over " ^
190 String.concat "," (List.map (NCicPp.ppterm ~metasenv ~subst ~context)args)));
191 let rc = mk_lambda metasenv subst context 0 [] argsty in
192 pp(lazy("LAMBDA_INTROS}"));
195 and instantiate rdb test_eq_only metasenv subst context n lc t swap =
196 (*D*) inside 'I'; try let rc =
197 pp (lazy(string_of_int n ^ " :=?= "^
198 NCicPp.ppterm ~metasenv ~subst ~context t));
199 let unify test_eq_only m s c t1 t2 =
200 if swap then unify rdb test_eq_only m s c t2 t1
201 else unify rdb test_eq_only m s c t1 t2
203 let has_tag = List.exists in
204 let tags, _, ty = NCicUtils.lookup_meta n metasenv in
206 let metasenv, subst, t =
208 | NCic.Implicit (`Typeof _) ->
209 pp(lazy("meta with no type"));
210 assert(has_tag ((=)`IsSort) tags);
213 let exc_to_be = fail_exc metasenv subst context (NCic.Meta (n,lc)) t in
215 try t, NCicTypeChecker.typeof ~subst ~metasenv context t
217 | NCicTypeChecker.AssertFailure msg ->
218 pp(lazy("we try to fix the sort\n"^Lazy.force msg^"\n"^NCicPp.ppmetasenv ~subst
220 let ft = fix_sorts swap exc_to_be t in
221 pp(lazy("unable to fix the sort"));
222 if ft == t then begin
223 raise (UnificationFailure (lazy ("unable to fix sorts of: "^
224 NCicPp.ppterm ~metasenv ~subst ~context t)))
226 (try ft, NCicTypeChecker.typeof ~subst ~metasenv context ft
227 with NCicTypeChecker.AssertFailure _ ->
228 raise (UnificationFailure (lazy
229 ("fix sorts generated an ill-typed: "^
230 NCicPp.ppterm ~metasenv ~subst ~context t))))
231 | NCicTypeChecker.TypeCheckerFailure msg ->
232 prerr_endline (Lazy.force msg);
233 prerr_endline (NCicPp.ppterm ~metasenv ~subst ~context t);
234 prerr_endline (ppcontext ~metasenv ~subst context);
235 prerr_endline (ppmetasenv ~subst metasenv);
239 | NCic.Implicit (`Typeof _) ->
240 raise (UnificationFailure(lazy "trying to unify a term with a type"))
242 let lty = NCicSubstitution.subst_meta lc ty in
243 pp (lazy ("On the types: " ^
244 NCicPp.ppterm ~metasenv ~subst ~context lty ^ " === " ^
245 NCicPp.ppterm ~metasenv ~subst ~context ty_t));
247 try unify test_eq_only metasenv subst context lty ty_t
248 with NCicEnvironment.BadConstraint _ as exc ->
249 let ty_t = fix_sorts swap exc_to_be ty_t in
250 try unify test_eq_only metasenv subst context lty ty_t
252 | NCicEnvironment.BadConstraint _
253 | UnificationFailure _ -> raise exc
257 (* viral sortification *)
258 let is_sort metasenv subst context t =
259 match NCicReduction.whd ~subst context t with
261 let tags, _, _ = NCicUtils.lookup_meta i metasenv in
262 has_tag ((=) `IsSort) tags
263 | NCic.Sort _ -> true
266 let rec sortify metasenv subst = function
267 | NCic.Implicit (`Typeof _)
268 | NCic.Sort _ as t -> metasenv, subst, t, 0
269 | NCic.Meta (i,_) as t ->
270 let tags, context, ty = NCicUtils.lookup_meta i metasenv in
271 if has_tag ((=) `IsSort) tags then metasenv, subst, t, i
273 let ty = NCicReduction.whd ~subst context ty in
274 let metasenv, subst, ty, _ = sortify metasenv subst ty in
275 let metasenv, j, m, _ =
276 NCicMetaSubst.mk_meta metasenv [] (`WithType ty)
278 pp(lazy("rimpiazzo " ^ string_of_int i^" con "^string_of_int j));
279 let metasenv,subst = unify test_eq_only metasenv subst context t m in
280 let j = if swap then i else j in
281 let tags, context, ty = NCicUtils.lookup_meta j metasenv in
282 let tags = `IsSort :: tags in
283 let metasenv = List.filter (fun x,_ -> x <> j) metasenv in
284 let metasenv = (j,(tags,context,ty)) ::metasenv in
285 metasenv, subst, m, j
287 if could_reduce t then raise (Uncertain(lazy "not a sort"))
288 else raise (UnificationFailure(lazy "not a sort"))
290 let metasenv, subst, _, n =
291 if has_tag ((=) `IsSort) tags then
292 let m,s,x,_ = sortify metasenv subst (NCicReduction.whd ~subst context t)
294 else if is_sort metasenv subst context t then
295 sortify metasenv subst (NCic.Meta (n,lc))
297 metasenv, subst, NCic.Rel ~-1,n
299 let tags, ctx, ty = NCicUtils.lookup_meta n metasenv in
303 - Meta sort === t -> check t is sort or sortify
304 - add tag `IsSort and set cc=[] to n and its pile
305 - se gli ancestor non sono sorte o meta... bum...
306 - cambiare in-place menv
307 - geneare meta fresh sorta e dall'alto al basso
308 - Meta _ === Meta sort -> sortify n (i.e. add `IsSort)
310 pp (lazy(string_of_int n ^ " := 111 = "^
311 NCicPp.ppterm ~metasenv ~subst ~context t));
312 let (metasenv, subst), t =
315 ~unify:(fun m s c t1 t2 ->
318 try Some (unify test_eq_only m s c t1 t2 )
319 with UnificationFailure _ | Uncertain _ -> None
322 metasenv subst context n lc t
323 with NCicMetaSubst.Uncertain msg ->
324 pp (lazy ("delift fails: " ^ Lazy.force msg));
325 raise (Uncertain msg)
326 | NCicMetaSubst.MetaSubstFailure msg ->
327 pp (lazy ("delift fails: " ^ Lazy.force msg));
328 raise (UnificationFailure msg)
330 pp (lazy(string_of_int n ^ " := 222 = "^
331 NCicPp.ppterm ~metasenv ~subst ~context:ctx t
332 ^ ppmetasenv ~subst metasenv));
333 (* Unifying the types may have already instantiated n. *)
335 let _, _,oldt,_ = NCicUtils.lookup_subst n subst in
336 let oldt = NCicSubstitution.subst_meta lc oldt in
337 let t = NCicSubstitution.subst_meta lc t in
338 (* conjecture: always fail --> occur check *)
339 unify test_eq_only metasenv subst context oldt t
340 with NCicUtils.Subst_not_found _ ->
341 (* by cumulativity when unify(?,Type_i)
342 * we could ? := Type_j with j <= i... *)
343 let subst = (n, (tags, ctx, t, ty)) :: subst in
344 pp (lazy ("?"^string_of_int n^" := "^NCicPp.ppterm
345 ~metasenv ~subst ~context (NCicSubstitution.subst_meta lc t)));
347 List.filter (fun (m,_) -> not (n = m)) metasenv
350 (*D*) in outside true; rc with exn -> outside false; raise exn
352 and unify rdb test_eq_only metasenv subst context t1 t2 =
353 (*D*) inside 'U'; try let rc =
354 let fo_unif test_eq_only metasenv subst t1 t2 =
355 (*D*) inside 'F'; try let rc =
356 pp (lazy(" " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " ==?== " ^
357 NCicPp.ppterm ~metasenv ~subst ~context t2 ^ ppmetasenv
363 | C.Appl [_], _ | _, C.Appl [_] | C.Appl [], _ | _, C.Appl []
364 | C.Appl (C.Appl _::_), _ | _, C.Appl (C.Appl _::_) ->
365 prerr_endline "Appl [Appl _;_] or Appl [] or Appl [_] invariant";
367 | (C.Sort (C.Type a), C.Sort (C.Type b)) when not test_eq_only ->
368 if NCicEnvironment.universe_leq a b then metasenv, subst
369 else raise (fail_exc metasenv subst context t1 t2)
370 | (C.Sort (C.Type a), C.Sort (C.Type b)) ->
371 if NCicEnvironment.universe_eq a b then metasenv, subst
372 else raise (fail_exc metasenv subst context t1 t2)
373 | (C.Sort C.Prop,C.Sort (C.Type _)) ->
374 if (not test_eq_only) then metasenv, subst
375 else raise (fail_exc metasenv subst context t1 t2)
377 | (C.Lambda (name1,s1,t1), C.Lambda(_,s2,t2))
378 | (C.Prod (name1,s1,t1), C.Prod(_,s2,t2)) ->
379 let metasenv, subst = unify rdb true metasenv subst context s1 s2 in
380 unify rdb test_eq_only metasenv subst ((name1, C.Decl s1)::context) t1 t2
381 | (C.LetIn (name1,ty1,s1,t1), C.LetIn(_,ty2,s2,t2)) ->
382 let metasenv,subst=unify rdb test_eq_only metasenv subst context ty1 ty2 in
383 let metasenv,subst=unify rdb test_eq_only metasenv subst context s1 s2 in
384 let context = (name1, C.Def (s1,ty1))::context in
385 unify rdb test_eq_only metasenv subst context t1 t2
387 | (C.Meta (n1,(s1,l1 as lc1)),C.Meta (n2,(s2,l2 as lc2))) when n1 = n2 ->
389 let l1 = NCicUtils.expand_local_context l1 in
390 let l2 = NCicUtils.expand_local_context l2 in
391 let metasenv, subst, to_restrict, _ =
393 (fun t1 t2 (metasenv, subst, to_restrict, i) ->
395 let metasenv, subst =
396 unify rdb test_eq_only metasenv subst context
397 (NCicSubstitution.lift s1 t1) (NCicSubstitution.lift s2 t2)
399 metasenv, subst, to_restrict, i-1
400 with UnificationFailure _ | Uncertain _ ->
401 metasenv, subst, i::to_restrict, i-1)
402 l1 l2 (metasenv, subst, [], List.length l1)
404 if to_restrict <> [] then
405 let metasenv, subst, _ =
406 NCicMetaSubst.restrict metasenv subst n1 to_restrict
411 | Invalid_argument _ -> assert false
412 | NCicMetaSubst.MetaSubstFailure msg ->
414 let _,_,term,_ = NCicUtils.lookup_subst n1 subst in
415 let term1 = NCicSubstitution.subst_meta lc1 term in
416 let term2 = NCicSubstitution.subst_meta lc2 term in
417 unify rdb test_eq_only metasenv subst context term1 term2
418 with NCicUtils.Subst_not_found _-> raise (UnificationFailure msg))
420 | _, NCic.Meta (n, _) when is_locked n subst ->
421 (let (metasenv, subst), i =
422 match NCicReduction.whd ~subst context t1 with
423 | NCic.Appl (NCic.Meta (i,l)::args) ->
424 let metasenv, subst, lambda_Mj =
425 lambda_intros rdb metasenv subst context t1 args
427 unify rdb test_eq_only metasenv subst context
428 (C.Meta (i,l)) lambda_Mj,
430 | NCic.Meta (i,_) -> (metasenv, subst), i
432 raise (UnificationFailure (lazy "Locked term vs non
433 flexible term; probably not saturated enough yet!"))
435 let t1 = NCicReduction.whd ~subst context t1 in
437 match t1 with NCic.Meta (j,l) -> j, l | _ -> assert false
439 let metasenv, subst =
440 instantiate rdb test_eq_only metasenv subst context j lj t2 true
442 (* We need to remove the out_scope_tags to avoid propagation of
443 them that triggers again the ad-hoc case *)
445 List.map (fun (i,(tag,ctx,bo,ty)) ->
448 (function `InScope | `OutScope _ -> false | _ -> true) tag
454 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
455 let term = eta_reduce subst term in
456 let subst = List.filter (fun (j,_) -> j <> i) subst in
457 metasenv, ((i, (name, ctx, term, ty)) :: subst)
458 with Not_found -> assert false))
460 | C.Meta (n,lc), t ->
462 let _,_,term,_ = NCicUtils.lookup_subst n subst in
463 let term = NCicSubstitution.subst_meta lc term in
464 unify rdb test_eq_only metasenv subst context term t
465 with NCicUtils.Subst_not_found _->
466 instantiate rdb test_eq_only metasenv subst context n lc
467 (NCicReduction.head_beta_reduce ~subst t) false)
469 | t, C.Meta (n,lc) ->
471 let _,_,term,_ = NCicUtils.lookup_subst n subst in
472 let term = NCicSubstitution.subst_meta lc term in
473 unify rdb test_eq_only metasenv subst context t term
474 with NCicUtils.Subst_not_found _->
475 instantiate rdb test_eq_only metasenv subst context n lc
476 (NCicReduction.head_beta_reduce ~subst t) true)
478 | NCic.Appl (NCic.Meta (i,l)::args), _ when List.mem_assoc i subst ->
479 let _,_,term,_ = NCicUtils.lookup_subst i subst in
480 let term = NCicSubstitution.subst_meta l term in
481 unify rdb test_eq_only metasenv subst context
482 (mk_appl ~upto:(List.length args) term args) t2
484 | _, NCic.Appl (NCic.Meta (i,l)::args) when List.mem_assoc i subst ->
485 let _,_,term,_ = NCicUtils.lookup_subst i subst in
486 let term = NCicSubstitution.subst_meta l term in
487 unify rdb test_eq_only metasenv subst context t1
488 (mk_appl ~upto:(List.length args) term args)
490 | NCic.Appl (NCic.Meta (i,_)::_ as l1),
491 NCic.Appl (NCic.Meta (j,_)::_ as l2) when i=j ->
494 (fun (metasenv, subst) t1 t2 ->
495 unify rdb test_eq_only metasenv subst context t1 t2)
496 (metasenv,subst) l1 l2
497 with Invalid_argument _ ->
498 raise (fail_exc metasenv subst context t1 t2))
500 | NCic.Appl (NCic.Meta (i,l)::args), _ ->
501 let metasenv, subst, lambda_Mj =
502 lambda_intros rdb metasenv subst context t1 args
504 let metasenv, subst =
505 unify rdb test_eq_only metasenv subst context
506 (C.Meta (i,l)) lambda_Mj
508 let metasenv, subst =
509 unify rdb test_eq_only metasenv subst context t1 t2
512 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
513 let term = eta_reduce subst term in
514 let subst = List.filter (fun (j,_) -> j <> i) subst in
515 metasenv, ((i, (name, ctx, term, ty)) :: subst)
516 with Not_found -> assert false)
518 | _, NCic.Appl (NCic.Meta (i,l)::args) ->
519 let metasenv, subst, lambda_Mj =
520 lambda_intros rdb metasenv subst context t2 args
522 let metasenv, subst =
523 unify rdb test_eq_only metasenv subst context
524 lambda_Mj (C.Meta (i,l))
526 let metasenv, subst =
527 unify rdb test_eq_only metasenv subst context t1 t2
530 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
531 let term = eta_reduce subst term in
532 let subst = List.filter (fun (j,_) -> j <> i) subst in
533 metasenv, ((i, (name, ctx, term, ty)) :: subst)
534 with Not_found -> assert false)
536 (* processing this case here we avoid a useless small delta step *)
537 | (C.Appl ((C.Const r1) as _hd1::tl1), C.Appl (C.Const r2::tl2))
539 let relevance = NCicEnvironment.get_relevance r1 in
540 let relevance = match r1 with
541 | Ref.Ref (_,Ref.Con (_,_,lno)) ->
543 try snd (HExtlib.split_nth lno relevance)
546 HExtlib.mk_list false lno @ relevance
549 let metasenv, subst, _ =
552 (fun (metasenv, subst, relevance) t1 t2 ->
554 match relevance with b::tl -> b,tl | _ -> true, [] in
555 let metasenv, subst =
556 try unify rdb test_eq_only metasenv subst context t1 t2
557 with UnificationFailure _ | Uncertain _ when not b ->
560 metasenv, subst, relevance)
561 (metasenv, subst, relevance) tl1 tl2
562 with Invalid_argument _ ->
563 raise (uncert_exc metasenv subst context t1 t2)
567 | (C.Match (Ref.Ref (_,Ref.Ind (_,tyno,_)) as ref1,outtype1,term1,pl1),
568 C.Match (ref2,outtype2,term2,pl2)) ->
569 let _,_,itl,_,_ = NCicEnvironment.get_checked_indtys ref1 in
570 let _,_,ty,_ = List.nth itl tyno in
571 let rec remove_prods ~subst context ty =
572 let ty = NCicReduction.whd ~subst context ty in
575 | C.Prod (name,so,ta) ->
576 remove_prods ~subst ((name,(C.Decl so))::context) ta
580 match remove_prods ~subst [] ty with
581 | C.Sort C.Prop -> true
584 if not (Ref.eq ref1 ref2) then
585 raise (uncert_exc metasenv subst context t1 t2)
587 let metasenv, subst =
588 unify rdb test_eq_only metasenv subst context outtype1 outtype2 in
589 let metasenv, subst =
590 try unify rdb test_eq_only metasenv subst context term1 term2
591 with UnificationFailure _ | Uncertain _ when is_prop ->
596 (fun (metasenv,subst) ->
597 unify rdb test_eq_only metasenv subst context)
598 (metasenv, subst) pl1 pl2
599 with Invalid_argument _ -> assert false)
600 | (C.Implicit _, _) | (_, C.Implicit _) -> assert false
601 | _ when NCicUntrusted.metas_of_term subst context t1 = [] &&
602 NCicUntrusted.metas_of_term subst context t2 = [] ->
603 raise (fail_exc metasenv subst context t1 t2)
604 | _ -> raise (uncert_exc metasenv subst context t1 t2)
605 (*D*) in outside true; rc with exn -> outside false; raise exn
607 let try_hints metasenv subst t1 t2 (* exc*) =
608 (*D*) inside 'H'; try let rc =
610 prerr_endline ("\nProblema:\n" ^
611 NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " =?= " ^
612 NCicPp.ppterm ~metasenv ~subst ~context t2);
615 NCicUnifHint.look_for_hint rdb metasenv subst context t1 t2
617 let rec cand_iter = function
618 | [] -> None (* raise exc *)
619 | (metasenv,(c1,c2),premises)::tl ->
620 pp (lazy ("\nProvo il candidato:\n" ^
624 NCicPp.ppterm ~metasenv ~subst ~context a ^ " =?= " ^
625 NCicPp.ppterm ~metasenv ~subst ~context b) premises) ^
626 "\n-------------------------------------------\n"^
627 NCicPp.ppterm ~metasenv ~subst ~context c1 ^ " = " ^
628 NCicPp.ppterm ~metasenv ~subst ~context c2));
630 (*D*) inside 'K'; try let rc =
632 fo_unif test_eq_only metasenv subst t1 c1 in
634 fo_unif test_eq_only metasenv subst c2 t2 in
637 (fun (metasenv, subst) (x,y) ->
638 unify rdb test_eq_only metasenv subst context x y)
639 (metasenv, subst) premises
641 Some (metasenv, subst)
642 (*D*) in outside true; rc with exn -> outside false; raise exn
644 UnificationFailure _ | Uncertain _ ->
648 (*D*) in outside true; rc with exn -> outside false; raise exn
650 let height_of = function
651 | NCic.Const (Ref.Ref (_,Ref.Def h))
652 | NCic.Const (Ref.Ref (_,Ref.Fix (_,_,h)))
653 | NCic.Appl(NCic.Const(Ref.Ref(_,Ref.Def h))::_)
654 | NCic.Appl(NCic.Const(Ref.Ref(_,Ref.Fix (_,_,h)))::_) -> h
657 let put_in_whd m1 m2 =
658 NCicReduction.reduce_machine ~delta:max_int ~subst context m1,
659 NCicReduction.reduce_machine ~delta:max_int ~subst context m2
661 let small_delta_step ~subst
662 ((_,_,t1,_ as m1, norm1) as x1) ((_,_,t2,_ as m2, norm2) as x2)
664 assert (not (norm1 && norm2));
666 x1,NCicReduction.reduce_machine ~delta:(height_of t2 -1) ~subst context m2
668 NCicReduction.reduce_machine ~delta:(height_of t1 -1) ~subst context m1,x2
670 let h1 = height_of t1 in
671 let h2 = height_of t2 in
672 let delta = if h1 = h2 then max 0 (h1 -1) else min h1 h2 in
673 NCicReduction.reduce_machine ~delta ~subst context m1,
674 NCicReduction.reduce_machine ~delta ~subst context m2
676 let rec unif_machines metasenv subst =
678 | ((k1,e1,t1,s1),norm1 as m1),((k2,e2,t2,s2),norm2 as m2) ->
679 (*D*) inside 'M'; try let rc =
681 NCicPp.ppterm ~metasenv ~subst ~context
682 (NCicReduction.unwind (k1,e1,t1,s1)) ^
684 NCicPp.ppterm ~metasenv ~subst ~context
685 (NCicReduction.unwind (k2,e2,t2,s2))));
686 pp (lazy (string_of_bool norm1 ^ " ?? " ^ string_of_bool norm2));
687 let relevance = [] (* TO BE UNDERSTOOD
689 | C.Const r -> NCicEnvironment.get_relevance r
691 let unif_from_stack t1 t2 b metasenv subst =
693 let t1 = NCicReduction.from_stack ~delta:max_int t1 in
694 let t2 = NCicReduction.from_stack ~delta:max_int t2 in
695 unif_machines metasenv subst (put_in_whd t1 t2)
696 with UnificationFailure _ | Uncertain _ when not b ->
699 let rec check_stack l1 l2 r todo =
701 | x1::tl1, x2::tl2, r::tr-> check_stack tl1 tl2 tr ((x1,x2,r)::todo)
702 | x1::tl1, x2::tl2, []-> check_stack tl1 tl2 [] ((x1,x2,true)::todo)
704 NCicReduction.unwind (k1,e1,t1,List.rev l1),
705 NCicReduction.unwind (k2,e2,t2,List.rev l2),
708 let hh1,hh2,todo=check_stack (List.rev s1) (List.rev s2) relevance [] in
710 let metasenv,subst = fo_unif test_eq_only metasenv subst hh1 hh2 in
712 (fun (metasenv,subst) (x1,x2,r) ->
713 unif_from_stack x1 x2 r metasenv subst
714 ) (metasenv,subst) todo
715 with UnificationFailure _ | Uncertain _ when not (norm1 && norm2) ->
716 unif_machines metasenv subst (small_delta_step ~subst m1 m2)
717 (*D*) in outside true; rc with exn -> outside false; raise exn
719 try fo_unif test_eq_only metasenv subst t1 t2
721 | UnificationFailure msg as exn ->
723 unif_machines metasenv subst
724 (put_in_whd (0,[],t1,[]) (0,[],t2,[]))
726 | UnificationFailure _ -> raise (UnificationFailure msg)
727 | Uncertain _ -> raise exn)
728 | Uncertain msg as exn ->
729 match try_hints metasenv subst t1 t2 with
733 unif_machines metasenv subst
734 (put_in_whd (0,[],t1,[]) (0,[],t2,[]))
736 | UnificationFailure _ -> raise (UnificationFailure msg)
737 | Uncertain _ -> raise exn
738 (*D*) in outside true; rc with exn -> outside false; raise exn
740 and delift_type_wrt_terms rdb metasenv subst context t args =
741 let (metasenv, subst), t =
744 ~unify:(fun m s c t1 t2 ->
747 try Some (unify rdb false m s c t1 t2 )
748 with UnificationFailure _ | Uncertain _ -> None
751 metasenv subst context 0 (0,NCic.Ctx (args @
752 List.rev (mk_irl (List.length context)))) t
753 with NCicMetaSubst.MetaSubstFailure _ -> (metasenv, subst), t
759 let unify rdb ?(test_eq_only=false) =
761 unify rdb test_eq_only;;
763 let fix_sorts = fix_sorts true (UnificationFailure (lazy "no sup"));;