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 name, ctx, ty = NCicUtils.lookup_meta n metasenv in
204 let metasenv, subst, t =
206 | NCic.Implicit (`Typeof _) ->
207 (match NCicReduction.whd ~subst context t with
208 NCic.Sort _ -> metasenv,subst,t
209 | NCic.Meta (i,_) when
210 let _,_,ty = NCicUtils.lookup_meta i metasenv in
212 NCic.Implicit (`Typeof _) -> true
216 let rec remove_and_hope i =
217 let _,ctx,ty = NCicUtils.lookup_meta i metasenv in
219 NCic.Implicit _ -> List.filter (fun i',_ -> i <> i') metasenv
221 match NCicReduction.whd ~subst ctx ty with
223 let metasenv = remove_and_hope j in
224 List.filter (fun i',_ -> i <> i') metasenv
225 | _ -> assert false (* NON POSSO RESTRINGERE *)
227 let metasenv = remove_and_hope i in
229 (i,([],[],NCic.Implicit (`Typeof i)))::
230 List.filter (fun i',_ -> i <> i') metasenv
233 | NCic.Appl (NCic.Meta _::_) ->
234 raise (Uncertain (lazy "Trying to instantiate a metavariable that represents a sort with a term"))
235 | t when could_reduce t ->
236 raise (Uncertain (lazy "Trying to instantiate a metavariable that represents a sort with a term"))
238 raise (UnificationFailure (lazy "Trying to instantiate a metavariable that represents a sort with a term")))
241 "typeof: " ^ NCicPp.ppterm ~metasenv ~subst ~context t ^
242 ppcontext ~metasenv ~subst context ^
243 ppmetasenv ~subst metasenv));
244 let exc_to_be = fail_exc metasenv subst context (NCic.Meta (n,lc)) t in
246 try t, NCicTypeChecker.typeof ~subst ~metasenv context t
248 | NCicTypeChecker.AssertFailure msg ->
249 (pp (lazy "fine typeof (fallimento)");
250 let ft = fix_sorts swap exc_to_be t in
252 (prerr_endline ( ("ILLTYPED: " ^
253 NCicPp.ppterm ~metasenv ~subst ~context t
254 ^ "\nBECAUSE:" ^ Lazy.force msg ^
255 ppcontext ~metasenv ~subst context ^
256 ppmetasenv ~subst metasenv
261 pp (lazy ("typeof: " ^
262 NCicPp.ppterm ~metasenv ~subst ~context ft));
263 ft, NCicTypeChecker.typeof ~subst ~metasenv context ft
264 with NCicTypeChecker.AssertFailure _ ->
266 | NCicTypeChecker.TypeCheckerFailure msg ->
267 prerr_endline (Lazy.force msg);
269 "typeof: " ^ NCicPp.ppterm ~metasenv ~subst ~context t ^
270 ppcontext ~metasenv ~subst context ^
271 ppmetasenv ~subst metasenv);
274 let lty = NCicSubstitution.subst_meta lc ty in
277 raise (UnificationFailure
278 (lazy "trying to unify a term with a type"))
280 pp (lazy ("On the types: " ^
281 NCicPp.ppterm ~metasenv ~subst ~context:ctx ty ^ " ~~~ " ^
282 NCicPp.ppterm ~metasenv ~subst ~context lty ^ " === "
283 ^ NCicPp.ppterm ~metasenv ~subst ~context ty_t));
286 unify test_eq_only metasenv subst context lty ty_t
287 with NCicEnvironment.BadConstraint _ as exc ->
288 let ty_t = fix_sorts swap exc_to_be ty_t in
289 try unify test_eq_only metasenv subst context lty ty_t
290 with _ -> raise exc in
293 pp (lazy(string_of_int n ^ " := 111 = "^
294 NCicPp.ppterm ~metasenv ~subst ~context t));
295 let (metasenv, subst), t =
298 ~unify:(fun m s c t1 t2 ->
301 try Some (unify test_eq_only m s c t1 t2 )
302 with UnificationFailure _ | Uncertain _ -> None
305 metasenv subst context n lc t
306 with NCicMetaSubst.Uncertain msg ->
307 pp (lazy ("delift fails: " ^ Lazy.force msg));
308 raise (Uncertain msg)
309 | NCicMetaSubst.MetaSubstFailure msg ->
310 pp (lazy ("delift fails: " ^ Lazy.force msg));
311 raise (UnificationFailure msg)
313 pp (lazy(string_of_int n ^ " := 222 = "^
314 NCicPp.ppterm ~metasenv ~subst ~context:ctx t
315 ^ ppmetasenv ~subst metasenv));
316 (* Unifying the types may have already instantiated n. *)
318 let _, _,oldt,_ = NCicUtils.lookup_subst n subst in
319 let oldt = NCicSubstitution.subst_meta lc oldt in
320 let t = NCicSubstitution.subst_meta lc t in
321 (* conjecture: always fail --> occur check *)
322 unify test_eq_only metasenv subst context oldt t
323 with NCicUtils.Subst_not_found _ ->
324 (* by cumulativity when unify(?,Type_i)
325 * we could ? := Type_j with j <= i... *)
326 let subst = (n, (name, ctx, t, ty)) :: subst in
327 pp (lazy ("?"^string_of_int n^" := "^NCicPp.ppterm
328 ~metasenv ~subst ~context (NCicSubstitution.subst_meta lc t)));
330 List.filter (fun (m,_) -> not (n = m)) metasenv
333 (*D*) in outside true; rc with exn -> outside false; raise exn
335 and unify rdb test_eq_only metasenv subst context t1 t2 =
336 (*D*) inside 'U'; try let rc =
337 let fo_unif test_eq_only metasenv subst t1 t2 =
338 (*D*) inside 'F'; try let rc =
339 pp (lazy(" " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " ==?== " ^
340 NCicPp.ppterm ~metasenv ~subst ~context t2 ^ ppmetasenv
346 | C.Appl [_], _ | _, C.Appl [_] | C.Appl [], _ | _, C.Appl []
347 | C.Appl (C.Appl _::_), _ | _, C.Appl (C.Appl _::_) ->
348 prerr_endline "Appl [Appl _;_] or Appl [] or Appl [_] invariant";
350 | (C.Sort (C.Type a), C.Sort (C.Type b)) when not test_eq_only ->
351 if NCicEnvironment.universe_leq a b then metasenv, subst
352 else raise (fail_exc metasenv subst context t1 t2)
353 | (C.Sort (C.Type a), C.Sort (C.Type b)) ->
354 if NCicEnvironment.universe_eq a b then metasenv, subst
355 else raise (fail_exc metasenv subst context t1 t2)
356 | (C.Sort C.Prop,C.Sort (C.Type _)) ->
357 if (not test_eq_only) then metasenv, subst
358 else raise (fail_exc metasenv subst context t1 t2)
360 | (C.Lambda (name1,s1,t1), C.Lambda(_,s2,t2))
361 | (C.Prod (name1,s1,t1), C.Prod(_,s2,t2)) ->
362 let metasenv, subst = unify rdb true metasenv subst context s1 s2 in
363 unify rdb test_eq_only metasenv subst ((name1, C.Decl s1)::context) t1 t2
364 | (C.LetIn (name1,ty1,s1,t1), C.LetIn(_,ty2,s2,t2)) ->
365 let metasenv,subst=unify rdb test_eq_only metasenv subst context ty1 ty2 in
366 let metasenv,subst=unify rdb test_eq_only metasenv subst context s1 s2 in
367 let context = (name1, C.Def (s1,ty1))::context in
368 unify rdb test_eq_only metasenv subst context t1 t2
370 | (C.Meta (n1,(s1,l1 as lc1)),C.Meta (n2,(s2,l2 as lc2))) when n1 = n2 ->
372 let l1 = NCicUtils.expand_local_context l1 in
373 let l2 = NCicUtils.expand_local_context l2 in
374 let metasenv, subst, to_restrict, _ =
376 (fun t1 t2 (metasenv, subst, to_restrict, i) ->
378 let metasenv, subst =
379 unify rdb test_eq_only metasenv subst context
380 (NCicSubstitution.lift s1 t1) (NCicSubstitution.lift s2 t2)
382 metasenv, subst, to_restrict, i-1
383 with UnificationFailure _ | Uncertain _ ->
384 metasenv, subst, i::to_restrict, i-1)
385 l1 l2 (metasenv, subst, [], List.length l1)
387 if to_restrict <> [] then
388 let metasenv, subst, _ =
389 NCicMetaSubst.restrict metasenv subst n1 to_restrict
394 | Invalid_argument _ -> assert false
395 | NCicMetaSubst.MetaSubstFailure msg ->
397 let _,_,term,_ = NCicUtils.lookup_subst n1 subst in
398 let term1 = NCicSubstitution.subst_meta lc1 term in
399 let term2 = NCicSubstitution.subst_meta lc2 term in
400 unify rdb test_eq_only metasenv subst context term1 term2
401 with NCicUtils.Subst_not_found _-> raise (UnificationFailure msg))
403 | _, NCic.Meta (n, _) when is_locked n subst ->
404 (let (metasenv, subst), i =
405 match NCicReduction.whd ~subst context t1 with
406 | NCic.Appl (NCic.Meta (i,l)::args) ->
407 let metasenv, subst, lambda_Mj =
408 lambda_intros rdb metasenv subst context t1 args
410 unify rdb test_eq_only metasenv subst context
411 (C.Meta (i,l)) lambda_Mj,
413 | NCic.Meta (i,_) -> (metasenv, subst), i
415 raise (UnificationFailure (lazy "Locked term vs non
416 flexible term; probably not saturated enough yet!"))
418 let t1 = NCicReduction.whd ~subst context t1 in
420 match t1 with NCic.Meta (j,l) -> j, l | _ -> assert false
422 let metasenv, subst =
423 instantiate rdb test_eq_only metasenv subst context j lj t2 true
425 (* We need to remove the out_scope_tags to avoid propagation of
426 them that triggers again the ad-hoc case *)
428 List.map (fun (i,(tag,ctx,bo,ty)) ->
431 (function `InScope | `OutScope _ -> false | _ -> true) tag
437 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
438 let term = eta_reduce subst term in
439 let subst = List.filter (fun (j,_) -> j <> i) subst in
440 metasenv, ((i, (name, ctx, term, ty)) :: subst)
441 with Not_found -> assert false))
443 | C.Meta (n,lc), t ->
445 let _,_,term,_ = NCicUtils.lookup_subst n subst in
446 let term = NCicSubstitution.subst_meta lc term in
447 unify rdb test_eq_only metasenv subst context term t
448 with NCicUtils.Subst_not_found _->
449 instantiate rdb test_eq_only metasenv subst context n lc
450 (NCicReduction.head_beta_reduce ~subst t) false)
452 | t, C.Meta (n,lc) ->
454 let _,_,term,_ = NCicUtils.lookup_subst n subst in
455 let term = NCicSubstitution.subst_meta lc term in
456 unify rdb test_eq_only metasenv subst context t term
457 with NCicUtils.Subst_not_found _->
458 instantiate rdb test_eq_only metasenv subst context n lc
459 (NCicReduction.head_beta_reduce ~subst t) true)
461 | NCic.Appl (NCic.Meta (i,l)::args), _ when List.mem_assoc i subst ->
462 let _,_,term,_ = NCicUtils.lookup_subst i subst in
463 let term = NCicSubstitution.subst_meta l term in
464 unify rdb test_eq_only metasenv subst context
465 (mk_appl ~upto:(List.length args) term args) t2
467 | _, NCic.Appl (NCic.Meta (i,l)::args) when List.mem_assoc i subst ->
468 let _,_,term,_ = NCicUtils.lookup_subst i subst in
469 let term = NCicSubstitution.subst_meta l term in
470 unify rdb test_eq_only metasenv subst context t1
471 (mk_appl ~upto:(List.length args) term args)
473 | NCic.Appl (NCic.Meta (i,_)::_ as l1),
474 NCic.Appl (NCic.Meta (j,_)::_ as l2) when i=j ->
477 (fun (metasenv, subst) t1 t2 ->
478 unify rdb test_eq_only metasenv subst context t1 t2)
479 (metasenv,subst) l1 l2
480 with Invalid_argument _ ->
481 raise (fail_exc metasenv subst context t1 t2))
483 | NCic.Appl (NCic.Meta (i,l)::args), _ ->
484 let metasenv, subst, lambda_Mj =
485 lambda_intros rdb metasenv subst context t1 args
487 let metasenv, subst =
488 unify rdb test_eq_only metasenv subst context
489 (C.Meta (i,l)) lambda_Mj
491 let metasenv, subst =
492 unify rdb test_eq_only metasenv subst context t1 t2
495 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
496 let term = eta_reduce subst term in
497 let subst = List.filter (fun (j,_) -> j <> i) subst in
498 metasenv, ((i, (name, ctx, term, ty)) :: subst)
499 with Not_found -> assert false)
501 | _, NCic.Appl (NCic.Meta (i,l)::args) ->
502 let metasenv, subst, lambda_Mj =
503 lambda_intros rdb metasenv subst context t2 args
505 let metasenv, subst =
506 unify rdb test_eq_only metasenv subst context
507 lambda_Mj (C.Meta (i,l))
509 let metasenv, subst =
510 unify rdb test_eq_only metasenv subst context t1 t2
513 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
514 let term = eta_reduce subst term in
515 let subst = List.filter (fun (j,_) -> j <> i) subst in
516 metasenv, ((i, (name, ctx, term, ty)) :: subst)
517 with Not_found -> assert false)
519 (* processing this case here we avoid a useless small delta step *)
520 | (C.Appl ((C.Const r1) as _hd1::tl1), C.Appl (C.Const r2::tl2))
522 let relevance = NCicEnvironment.get_relevance r1 in
523 let relevance = match r1 with
524 | Ref.Ref (_,Ref.Con (_,_,lno)) ->
526 try snd (HExtlib.split_nth lno relevance)
529 HExtlib.mk_list false lno @ relevance
532 let metasenv, subst, _ =
535 (fun (metasenv, subst, relevance) t1 t2 ->
537 match relevance with b::tl -> b,tl | _ -> true, [] in
538 let metasenv, subst =
539 try unify rdb test_eq_only metasenv subst context t1 t2
540 with UnificationFailure _ | Uncertain _ when not b ->
543 metasenv, subst, relevance)
544 (metasenv, subst, relevance) tl1 tl2
545 with Invalid_argument _ ->
546 raise (uncert_exc metasenv subst context t1 t2)
550 | (C.Match (Ref.Ref (_,Ref.Ind (_,tyno,_)) as ref1,outtype1,term1,pl1),
551 C.Match (ref2,outtype2,term2,pl2)) ->
552 let _,_,itl,_,_ = NCicEnvironment.get_checked_indtys ref1 in
553 let _,_,ty,_ = List.nth itl tyno in
554 let rec remove_prods ~subst context ty =
555 let ty = NCicReduction.whd ~subst context ty in
558 | C.Prod (name,so,ta) ->
559 remove_prods ~subst ((name,(C.Decl so))::context) ta
563 match remove_prods ~subst [] ty with
564 | C.Sort C.Prop -> true
567 if not (Ref.eq ref1 ref2) then
568 raise (uncert_exc metasenv subst context t1 t2)
570 let metasenv, subst =
571 unify rdb test_eq_only metasenv subst context outtype1 outtype2 in
572 let metasenv, subst =
573 try unify rdb test_eq_only metasenv subst context term1 term2
574 with UnificationFailure _ | Uncertain _ when is_prop ->
579 (fun (metasenv,subst) ->
580 unify rdb test_eq_only metasenv subst context)
581 (metasenv, subst) pl1 pl2
582 with Invalid_argument _ -> assert false)
583 | (C.Implicit _, _) | (_, C.Implicit _) -> assert false
584 | _ when NCicUntrusted.metas_of_term subst context t1 = [] &&
585 NCicUntrusted.metas_of_term subst context t2 = [] ->
586 raise (fail_exc metasenv subst context t1 t2)
587 | _ -> raise (uncert_exc metasenv subst context t1 t2)
588 (*D*) in outside true; rc with exn -> outside false; raise exn
590 let try_hints metasenv subst t1 t2 (* exc*) =
591 (*D*) inside 'H'; try let rc =
593 prerr_endline ("\nProblema:\n" ^
594 NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " =?= " ^
595 NCicPp.ppterm ~metasenv ~subst ~context t2);
598 NCicUnifHint.look_for_hint rdb metasenv subst context t1 t2
600 let rec cand_iter = function
601 | [] -> None (* raise exc *)
602 | (metasenv,(c1,c2),premises)::tl ->
603 pp (lazy ("\nProvo il candidato:\n" ^
607 NCicPp.ppterm ~metasenv ~subst ~context a ^ " =?= " ^
608 NCicPp.ppterm ~metasenv ~subst ~context b) premises) ^
609 "\n-------------------------------------------\n"^
610 NCicPp.ppterm ~metasenv ~subst ~context c1 ^ " = " ^
611 NCicPp.ppterm ~metasenv ~subst ~context c2));
613 (*D*) inside 'K'; try let rc =
615 fo_unif test_eq_only metasenv subst t1 c1 in
617 fo_unif test_eq_only metasenv subst c2 t2 in
620 (fun (metasenv, subst) (x,y) ->
621 unify rdb test_eq_only metasenv subst context x y)
622 (metasenv, subst) premises
624 Some (metasenv, subst)
625 (*D*) in outside true; rc with exn -> outside false; raise exn
627 UnificationFailure _ | Uncertain _ ->
631 (*D*) in outside true; rc with exn -> outside false; raise exn
633 let height_of = function
634 | NCic.Const (Ref.Ref (_,Ref.Def h))
635 | NCic.Const (Ref.Ref (_,Ref.Fix (_,_,h)))
636 | NCic.Appl(NCic.Const(Ref.Ref(_,Ref.Def h))::_)
637 | NCic.Appl(NCic.Const(Ref.Ref(_,Ref.Fix (_,_,h)))::_) -> h
640 let put_in_whd m1 m2 =
641 NCicReduction.reduce_machine ~delta:max_int ~subst context m1,
642 NCicReduction.reduce_machine ~delta:max_int ~subst context m2
644 let small_delta_step ~subst
645 ((_,_,t1,_ as m1, norm1) as x1) ((_,_,t2,_ as m2, norm2) as x2)
647 assert (not (norm1 && norm2));
649 x1,NCicReduction.reduce_machine ~delta:(height_of t2 -1) ~subst context m2
651 NCicReduction.reduce_machine ~delta:(height_of t1 -1) ~subst context m1,x2
653 let h1 = height_of t1 in
654 let h2 = height_of t2 in
655 let delta = if h1 = h2 then max 0 (h1 -1) else min h1 h2 in
656 NCicReduction.reduce_machine ~delta ~subst context m1,
657 NCicReduction.reduce_machine ~delta ~subst context m2
659 let rec unif_machines metasenv subst =
661 | ((k1,e1,t1,s1),norm1 as m1),((k2,e2,t2,s2),norm2 as m2) ->
662 (*D*) inside 'M'; try let rc =
664 NCicPp.ppterm ~metasenv ~subst ~context
665 (NCicReduction.unwind (k1,e1,t1,s1)) ^
667 NCicPp.ppterm ~metasenv ~subst ~context
668 (NCicReduction.unwind (k2,e2,t2,s2))));
669 pp (lazy (string_of_bool norm1 ^ " ?? " ^ string_of_bool norm2));
670 let relevance = [] (* TO BE UNDERSTOOD
672 | C.Const r -> NCicEnvironment.get_relevance r
674 let unif_from_stack t1 t2 b metasenv subst =
676 let t1 = NCicReduction.from_stack ~delta:max_int t1 in
677 let t2 = NCicReduction.from_stack ~delta:max_int t2 in
678 unif_machines metasenv subst (put_in_whd t1 t2)
679 with UnificationFailure _ | Uncertain _ when not b ->
682 let rec check_stack l1 l2 r todo =
684 | x1::tl1, x2::tl2, r::tr-> check_stack tl1 tl2 tr ((x1,x2,r)::todo)
685 | x1::tl1, x2::tl2, []-> check_stack tl1 tl2 [] ((x1,x2,true)::todo)
687 NCicReduction.unwind (k1,e1,t1,List.rev l1),
688 NCicReduction.unwind (k2,e2,t2,List.rev l2),
691 let hh1,hh2,todo=check_stack (List.rev s1) (List.rev s2) relevance [] in
693 let metasenv,subst = fo_unif test_eq_only metasenv subst hh1 hh2 in
695 (fun (metasenv,subst) (x1,x2,r) ->
696 unif_from_stack x1 x2 r metasenv subst
697 ) (metasenv,subst) todo
698 with UnificationFailure _ | Uncertain _ when not (norm1 && norm2) ->
699 unif_machines metasenv subst (small_delta_step ~subst m1 m2)
700 (*D*) in outside true; rc with exn -> outside false; raise exn
702 try fo_unif test_eq_only metasenv subst t1 t2
704 | UnificationFailure msg as exn ->
706 unif_machines metasenv subst
707 (put_in_whd (0,[],t1,[]) (0,[],t2,[]))
709 | UnificationFailure _ -> raise (UnificationFailure msg)
710 | Uncertain _ -> raise exn)
711 | Uncertain msg as exn ->
712 match try_hints metasenv subst t1 t2 with
716 unif_machines metasenv subst
717 (put_in_whd (0,[],t1,[]) (0,[],t2,[]))
719 | UnificationFailure _ -> raise (UnificationFailure msg)
720 | Uncertain _ -> raise exn
721 (*D*) in outside true; rc with exn -> outside false; raise exn
723 and delift_type_wrt_terms rdb metasenv subst context t args =
724 let (metasenv, subst), t =
727 ~unify:(fun m s c t1 t2 ->
730 try Some (unify rdb false m s c t1 t2 )
731 with UnificationFailure _ | Uncertain _ -> None
734 metasenv subst context 0 (0,NCic.Ctx (args @
735 List.rev (mk_irl (List.length context)))) t
736 with NCicMetaSubst.MetaSubstFailure _ -> (metasenv, subst), t
742 let unify rdb ?(test_eq_only=false) =
744 unify rdb test_eq_only;;
746 let fix_sorts = fix_sorts true (UnificationFailure (lazy "no sup"));;