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 | Some 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 let rec lambda_intros rdb metasenv subst context t args =
145 let tty = NCicTypeChecker.typeof ~metasenv ~subst context t in
148 (fun arg -> arg, NCicTypeChecker.typeof ~metasenv ~subst context arg) args in
149 let context_of_args = context in
150 let rec mk_lambda metasenv subst context n processed_args = function
152 let metasenv, _, bo, _ =
153 NCicMetaSubst.mk_meta metasenv context
154 (`WithType (NCicSubstitution.lift n tty))
159 NCicPp.ppterm ~metasenv ~subst ~context:context_of_args arg ^ ":" ^
160 NCicPp.ppterm ~metasenv ~subst ~context:context_of_args ty));
161 let metasenv, subst, telescopic_ty =
162 if processed_args = [] then metasenv, subst, ty else
163 let _ = pp(lazy("delift")) in
164 delift_type_wrt_terms rdb metasenv subst context_of_args ty
165 (List.rev processed_args)
168 let name = "HBeta"^string_of_int n in
169 let metasenv, subst, bo =
170 mk_lambda metasenv subst ((name,NCic.Decl telescopic_ty)::context) (n+1)
171 (arg::processed_args) tail
173 metasenv, subst, NCic.Lambda (name, telescopic_ty, bo)
175 pp(lazy("LAMBDA_INTROS{ " ^
176 NCicPp.ppterm ~metasenv ~subst ~context t ^ ":" ^
177 NCicPp.ppterm ~metasenv ~subst ~context tty ^ " over " ^
178 String.concat "," (List.map (NCicPp.ppterm ~metasenv ~subst ~context)args)));
179 let rc = mk_lambda metasenv subst context 0 [] argsty in
180 pp(lazy("LAMBDA_INTROS}"));
183 and instantiate rdb test_eq_only metasenv subst context n lc t swap =
184 (*D*) inside 'I'; try let rc =
185 pp (lazy(string_of_int n ^ " :=?= "^
186 NCicPp.ppterm ~metasenv ~subst ~context t));
187 let unify test_eq_only m s c t1 t2 =
188 if swap then unify rdb test_eq_only m s c t2 t1
189 else unify rdb test_eq_only m s c t1 t2
191 let name, ctx, ty = NCicUtils.lookup_meta n metasenv in
192 let metasenv, subst, t =
194 | NCic.Implicit (`Typeof _) ->
198 NCicTypeChecker.typeof ~subst ~metasenv context t*)
200 NCicTypeChecker.AssertFailure msg ->
202 fail_exc metasenv subst context (NCic.Meta (n,lc)) t in
203 pp (lazy "fine typeof (fallimento)");
204 let ft = fix_sorts swap exc_to_be t in
206 (prerr_endline ( ("ILLTYPED: " ^
207 NCicPp.ppterm ~metasenv ~subst ~context t
208 ^ "\nBECAUSE:" ^ Lazy.force msg ^
209 ppcontext ~metasenv ~subst context ^
210 ppmetasenv ~subst metasenv
215 pp (lazy ("typeof: " ^
216 NCicPp.ppterm ~metasenv ~subst ~context ft));
217 NCicTypeChecker.typeof ~subst ~metasenv context ft
218 with NCicTypeChecker.AssertFailure _ ->
220 | NCicTypeChecker.TypeCheckerFailure _ -> assert false
222 match NCicReduction.whd ~subst context ty_t with
223 NCic.Sort _ -> metasenv,subst, t
224 | NCic.Meta _ -> metasenv,subst,t (* CSC: TO BE IMPLEMENTED *)
225 | _ -> raise (Uncertain (lazy "Trying to instantiate a metavariable that represents a sort with a term")))
226 (*CSC: TO BE IMPLEMENTED: UnificationFailure of string Lazy.t;; *)
227 (* fix_sorts swap metasenv subst context (NCic.Meta(n,lc)) t *)
230 "typeof: " ^ NCicPp.ppterm ~metasenv ~subst ~context t ^
231 ppcontext ~metasenv ~subst context ^
232 ppmetasenv ~subst metasenv));
233 let exc_to_be = fail_exc metasenv subst context (NCic.Meta (n,lc)) t in
235 try t, NCicTypeChecker.typeof ~subst ~metasenv context t
237 | NCicTypeChecker.AssertFailure msg ->
238 (pp (lazy "fine typeof (fallimento)");
239 let ft = fix_sorts swap exc_to_be t in
241 (prerr_endline ( ("ILLTYPED: " ^
242 NCicPp.ppterm ~metasenv ~subst ~context t
243 ^ "\nBECAUSE:" ^ Lazy.force msg ^
244 ppcontext ~metasenv ~subst context ^
245 ppmetasenv ~subst metasenv
250 pp (lazy ("typeof: " ^
251 NCicPp.ppterm ~metasenv ~subst ~context ft));
252 ft, NCicTypeChecker.typeof ~subst ~metasenv context ft
253 with NCicTypeChecker.AssertFailure _ ->
255 | NCicTypeChecker.TypeCheckerFailure msg ->
256 prerr_endline (Lazy.force msg);
258 "typeof: " ^ NCicPp.ppterm ~metasenv ~subst ~context t ^
259 ppcontext ~metasenv ~subst context ^
260 ppmetasenv ~subst metasenv);
263 let lty = NCicSubstitution.subst_meta lc ty in
266 raise (UnificationFailure
267 (lazy "trying to unify a term with a type"))
269 pp (lazy ("On the types: " ^
270 NCicPp.ppterm ~metasenv ~subst ~context:ctx ty ^ " ~~~ " ^
271 NCicPp.ppterm ~metasenv ~subst ~context lty ^ " === "
272 ^ NCicPp.ppterm ~metasenv ~subst ~context ty_t));
275 unify test_eq_only metasenv subst context lty ty_t
276 with NCicEnvironment.BadConstraint _ as exc ->
277 let ty_t = fix_sorts swap exc_to_be ty_t in
278 try unify test_eq_only metasenv subst context lty ty_t
279 with _ -> raise exc in
282 pp (lazy(string_of_int n ^ " := 111 = "^
283 NCicPp.ppterm ~metasenv ~subst ~context t));
284 let (metasenv, subst), t =
287 ~unify:(fun m s c t1 t2 ->
290 try Some (unify test_eq_only m s c t1 t2 )
291 with UnificationFailure _ | Uncertain _ -> None
294 metasenv subst context n lc t
295 with NCicMetaSubst.Uncertain msg ->
296 pp (lazy ("delift fails: " ^ Lazy.force msg));
297 raise (Uncertain msg)
298 | NCicMetaSubst.MetaSubstFailure msg ->
299 pp (lazy ("delift fails: " ^ Lazy.force msg));
300 raise (UnificationFailure msg)
302 pp (lazy(string_of_int n ^ " := 222 = "^
303 NCicPp.ppterm ~metasenv ~subst ~context:ctx t
304 ^ ppmetasenv ~subst metasenv));
305 (* Unifying the types may have already instantiated n. *)
307 let _, _,oldt,_ = NCicUtils.lookup_subst n subst in
308 let oldt = NCicSubstitution.subst_meta lc oldt in
309 let t = NCicSubstitution.subst_meta lc t in
310 (* conjecture: always fail --> occur check *)
311 unify test_eq_only metasenv subst context oldt t
312 with NCicUtils.Subst_not_found _ ->
313 (* by cumulativity when unify(?,Type_i)
314 * we could ? := Type_j with j <= i... *)
315 let subst = (n, (name, ctx, t, ty)) :: subst in
316 pp (lazy ("?"^string_of_int n^" := "^NCicPp.ppterm
317 ~metasenv ~subst ~context (NCicSubstitution.subst_meta lc t)));
319 List.filter (fun (m,_) -> not (n = m)) metasenv
322 (*D*) in outside true; rc with exn -> outside false; raise exn
324 and unify rdb test_eq_only metasenv subst context t1 t2 =
325 (*D*) inside 'U'; try let rc =
326 let fo_unif test_eq_only metasenv subst t1 t2 =
327 (*D*) inside 'F'; try let rc =
328 pp (lazy(" " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " ==?== " ^
329 NCicPp.ppterm ~metasenv ~subst ~context t2 ^ ppmetasenv
335 | C.Appl [_], _ | _, C.Appl [_] | C.Appl [], _ | _, C.Appl []
336 | C.Appl (C.Appl _::_), _ | _, C.Appl (C.Appl _::_) ->
337 prerr_endline "Appl [Appl _;_] or Appl [] or Appl [_] invariant";
339 | (C.Sort (C.Type a), C.Sort (C.Type b)) when not test_eq_only ->
340 if NCicEnvironment.universe_leq a b then metasenv, subst
341 else raise (fail_exc metasenv subst context t1 t2)
342 | (C.Sort (C.Type a), C.Sort (C.Type b)) ->
343 if NCicEnvironment.universe_eq a b then metasenv, subst
344 else raise (fail_exc metasenv subst context t1 t2)
345 | (C.Sort C.Prop,C.Sort (C.Type _)) ->
346 if (not test_eq_only) then metasenv, subst
347 else raise (fail_exc metasenv subst context t1 t2)
349 | (C.Lambda (name1,s1,t1), C.Lambda(_,s2,t2))
350 | (C.Prod (name1,s1,t1), C.Prod(_,s2,t2)) ->
351 let metasenv, subst = unify rdb true metasenv subst context s1 s2 in
352 unify rdb test_eq_only metasenv subst ((name1, C.Decl s1)::context) t1 t2
353 | (C.LetIn (name1,ty1,s1,t1), C.LetIn(_,ty2,s2,t2)) ->
354 let metasenv,subst=unify rdb test_eq_only metasenv subst context ty1 ty2 in
355 let metasenv,subst=unify rdb test_eq_only metasenv subst context s1 s2 in
356 let context = (name1, C.Def (s1,ty1))::context in
357 unify rdb test_eq_only metasenv subst context t1 t2
359 | (C.Meta (n1,(s1,l1 as lc1)),C.Meta (n2,(s2,l2 as lc2))) when n1 = n2 ->
361 let l1 = NCicUtils.expand_local_context l1 in
362 let l2 = NCicUtils.expand_local_context l2 in
363 let metasenv, subst, to_restrict, _ =
365 (fun t1 t2 (metasenv, subst, to_restrict, i) ->
367 let metasenv, subst =
368 unify rdb test_eq_only metasenv subst context
369 (NCicSubstitution.lift s1 t1) (NCicSubstitution.lift s2 t2)
371 metasenv, subst, to_restrict, i-1
372 with UnificationFailure _ | Uncertain _ ->
373 metasenv, subst, i::to_restrict, i-1)
374 l1 l2 (metasenv, subst, [], List.length l1)
376 if to_restrict <> [] then
377 let metasenv, subst, _ =
378 NCicMetaSubst.restrict metasenv subst n1 to_restrict
383 | Invalid_argument _ -> assert false
384 | NCicMetaSubst.MetaSubstFailure msg ->
386 let _,_,term,_ = NCicUtils.lookup_subst n1 subst in
387 let term1 = NCicSubstitution.subst_meta lc1 term in
388 let term2 = NCicSubstitution.subst_meta lc2 term in
389 unify rdb test_eq_only metasenv subst context term1 term2
390 with NCicUtils.Subst_not_found _-> raise (UnificationFailure msg))
392 | _, NCic.Meta (n, _) when is_locked n subst ->
393 (let (metasenv, subst), i =
394 match NCicReduction.whd ~subst context t1 with
395 | NCic.Appl (NCic.Meta (i,l)::args) ->
396 let metasenv, subst, lambda_Mj =
397 lambda_intros rdb metasenv subst context t1 args
399 unify rdb test_eq_only metasenv subst context
400 (C.Meta (i,l)) lambda_Mj,
402 | NCic.Meta (i,_) -> (metasenv, subst), i
404 raise (UnificationFailure (lazy "Locked term vs non
405 flexible term; probably not saturated enough yet!"))
407 let t1 = NCicReduction.whd ~subst context t1 in
409 match t1 with NCic.Meta (j,l) -> j, l | _ -> assert false
411 let metasenv, subst =
412 instantiate rdb test_eq_only metasenv subst context j lj t2 true
414 (* We need to remove the out_scope_tags to avoid propagation of
415 them that triggers again the ad-hoc case *)
417 List.map (fun (i,(tag,ctx,bo,ty)) ->
421 tag = NCicMetaSubst.in_scope_tag
422 || NCicMetaSubst.is_out_scope_tag tag -> None
429 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
430 let term = eta_reduce subst term in
431 let subst = List.filter (fun (j,_) -> j <> i) subst in
432 metasenv, ((i, (name, ctx, term, ty)) :: subst)
433 with Not_found -> assert false))
435 | C.Meta (n,lc), t ->
437 let _,_,term,_ = NCicUtils.lookup_subst n subst in
438 let term = NCicSubstitution.subst_meta lc term in
439 unify rdb test_eq_only metasenv subst context term t
440 with NCicUtils.Subst_not_found _->
441 instantiate rdb test_eq_only metasenv subst context n lc
442 (NCicReduction.head_beta_reduce ~subst t) false)
444 | t, C.Meta (n,lc) ->
446 let _,_,term,_ = NCicUtils.lookup_subst n subst in
447 let term = NCicSubstitution.subst_meta lc term in
448 unify rdb test_eq_only metasenv subst context t term
449 with NCicUtils.Subst_not_found _->
450 instantiate rdb test_eq_only metasenv subst context n lc
451 (NCicReduction.head_beta_reduce ~subst t) true)
453 | NCic.Appl (NCic.Meta (i,l)::args), _ when List.mem_assoc i subst ->
454 let _,_,term,_ = NCicUtils.lookup_subst i subst in
455 let term = NCicSubstitution.subst_meta l term in
456 unify rdb test_eq_only metasenv subst context
457 (mk_appl ~upto:(List.length args) term args) t2
459 | _, NCic.Appl (NCic.Meta (i,l)::args) when List.mem_assoc i subst ->
460 let _,_,term,_ = NCicUtils.lookup_subst i subst in
461 let term = NCicSubstitution.subst_meta l term in
462 unify rdb test_eq_only metasenv subst context t1
463 (mk_appl ~upto:(List.length args) term args)
465 | NCic.Appl (NCic.Meta (i,_)::_ as l1),
466 NCic.Appl (NCic.Meta (j,_)::_ as l2) when i=j ->
469 (fun (metasenv, subst) t1 t2 ->
470 unify rdb test_eq_only metasenv subst context t1 t2)
471 (metasenv,subst) l1 l2
472 with Invalid_argument _ ->
473 raise (fail_exc metasenv subst context t1 t2))
475 | NCic.Appl (NCic.Meta (i,l)::args), _ ->
476 let metasenv, subst, lambda_Mj =
477 lambda_intros rdb metasenv subst context t1 args
479 let metasenv, subst =
480 unify rdb test_eq_only metasenv subst context
481 (C.Meta (i,l)) lambda_Mj
483 let metasenv, subst =
484 unify rdb test_eq_only metasenv subst context t1 t2
487 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
488 let term = eta_reduce subst term in
489 let subst = List.filter (fun (j,_) -> j <> i) subst in
490 metasenv, ((i, (name, ctx, term, ty)) :: subst)
491 with Not_found -> assert false)
493 | _, NCic.Appl (NCic.Meta (i,l)::args) ->
494 let metasenv, subst, lambda_Mj =
495 lambda_intros rdb metasenv subst context t2 args
497 let metasenv, subst =
498 unify rdb test_eq_only metasenv subst context
499 lambda_Mj (C.Meta (i,l))
501 let metasenv, subst =
502 unify rdb test_eq_only metasenv subst context t1 t2
505 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
506 let term = eta_reduce subst term in
507 let subst = List.filter (fun (j,_) -> j <> i) subst in
508 metasenv, ((i, (name, ctx, term, ty)) :: subst)
509 with Not_found -> assert false)
511 (* processing this case here we avoid a useless small delta step *)
512 | (C.Appl ((C.Const r1) as _hd1::tl1), C.Appl (C.Const r2::tl2))
514 let relevance = NCicEnvironment.get_relevance r1 in
515 let relevance = match r1 with
516 | Ref.Ref (_,Ref.Con (_,_,lno)) ->
518 try snd (HExtlib.split_nth lno relevance)
521 HExtlib.mk_list false lno @ relevance
524 let metasenv, subst, _ =
527 (fun (metasenv, subst, relevance) t1 t2 ->
529 match relevance with b::tl -> b,tl | _ -> true, [] in
530 let metasenv, subst =
531 try unify rdb test_eq_only metasenv subst context t1 t2
532 with UnificationFailure _ | Uncertain _ when not b ->
535 metasenv, subst, relevance)
536 (metasenv, subst, relevance) tl1 tl2
537 with Invalid_argument _ ->
538 raise (uncert_exc metasenv subst context t1 t2)
542 | (C.Match (Ref.Ref (_,Ref.Ind (_,tyno,_)) as ref1,outtype1,term1,pl1),
543 C.Match (ref2,outtype2,term2,pl2)) ->
544 let _,_,itl,_,_ = NCicEnvironment.get_checked_indtys ref1 in
545 let _,_,ty,_ = List.nth itl tyno in
546 let rec remove_prods ~subst context ty =
547 let ty = NCicReduction.whd ~subst context ty in
550 | C.Prod (name,so,ta) ->
551 remove_prods ~subst ((name,(C.Decl so))::context) ta
555 match remove_prods ~subst [] ty with
556 | C.Sort C.Prop -> true
559 if not (Ref.eq ref1 ref2) then
560 raise (uncert_exc metasenv subst context t1 t2)
562 let metasenv, subst =
563 unify rdb test_eq_only metasenv subst context outtype1 outtype2 in
564 let metasenv, subst =
565 try unify rdb test_eq_only metasenv subst context term1 term2
566 with UnificationFailure _ | Uncertain _ when is_prop ->
571 (fun (metasenv,subst) ->
572 unify rdb test_eq_only metasenv subst context)
573 (metasenv, subst) pl1 pl2
574 with Invalid_argument _ ->
575 raise (uncert_exc metasenv subst context t1 t2))
576 | (C.Implicit _, _) | (_, C.Implicit _) -> assert false
577 | _ when NCicUntrusted.metas_of_term subst context t1 = [] &&
578 NCicUntrusted.metas_of_term subst context t2 = [] ->
579 raise (fail_exc metasenv subst context t1 t2)
580 | _ -> raise (uncert_exc metasenv subst context t1 t2)
581 (*D*) in outside true; rc with exn -> outside false; raise exn
583 let try_hints metasenv subst t1 t2 (* exc*) =
584 (*D*) inside 'H'; try let rc =
586 prerr_endline ("\nProblema:\n" ^
587 NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " =?= " ^
588 NCicPp.ppterm ~metasenv ~subst ~context t2);
591 NCicUnifHint.look_for_hint rdb metasenv subst context t1 t2
593 let rec cand_iter = function
594 | [] -> None (* raise exc *)
595 | (metasenv,(c1,c2),premises)::tl ->
596 pp (lazy ("\nProvo il candidato:\n" ^
600 NCicPp.ppterm ~metasenv ~subst ~context a ^ " =?= " ^
601 NCicPp.ppterm ~metasenv ~subst ~context b) premises) ^
602 "\n-------------------------------------------\n"^
603 NCicPp.ppterm ~metasenv ~subst ~context c1 ^ " = " ^
604 NCicPp.ppterm ~metasenv ~subst ~context c2));
606 (*D*) inside 'K'; try let rc =
608 fo_unif test_eq_only metasenv subst t1 c1 in
610 fo_unif test_eq_only metasenv subst c2 t2 in
613 (fun (metasenv, subst) (x,y) ->
614 unify rdb test_eq_only metasenv subst context x y)
615 (metasenv, subst) premises
617 Some (metasenv, subst)
618 (*D*) in outside true; rc with exn -> outside false; raise exn
620 UnificationFailure _ | Uncertain _ ->
624 (*D*) in outside true; rc with exn -> outside false; raise exn
626 let height_of = function
627 | NCic.Const (Ref.Ref (_,Ref.Def h))
628 | NCic.Const (Ref.Ref (_,Ref.Fix (_,_,h)))
629 | NCic.Appl(NCic.Const(Ref.Ref(_,Ref.Def h))::_)
630 | NCic.Appl(NCic.Const(Ref.Ref(_,Ref.Fix (_,_,h)))::_) -> h
633 let put_in_whd m1 m2 =
634 NCicReduction.reduce_machine ~delta:max_int ~subst context m1,
635 NCicReduction.reduce_machine ~delta:max_int ~subst context m2
637 let small_delta_step ~subst
638 ((_,_,t1,_ as m1, norm1) as x1) ((_,_,t2,_ as m2, norm2) as x2)
640 assert (not (norm1 && norm2));
642 x1,NCicReduction.reduce_machine ~delta:(height_of t2 -1) ~subst context m2
644 NCicReduction.reduce_machine ~delta:(height_of t1 -1) ~subst context m1,x2
646 let h1 = height_of t1 in
647 let h2 = height_of t2 in
648 let delta = if h1 = h2 then max 0 (h1 -1) else min h1 h2 in
649 NCicReduction.reduce_machine ~delta ~subst context m1,
650 NCicReduction.reduce_machine ~delta ~subst context m2
652 let rec unif_machines metasenv subst =
654 | ((k1,e1,t1,s1),norm1 as m1),((k2,e2,t2,s2),norm2 as m2) ->
655 (*D*) inside 'M'; try let rc =
657 NCicPp.ppterm ~metasenv ~subst ~context
658 (NCicReduction.unwind (k1,e1,t1,s1)) ^
660 NCicPp.ppterm ~metasenv ~subst ~context
661 (NCicReduction.unwind (k2,e2,t2,s2))));
662 pp (lazy (string_of_bool norm1 ^ " ?? " ^ string_of_bool norm2));
663 let relevance = [] (* TO BE UNDERSTOOD
665 | C.Const r -> NCicEnvironment.get_relevance r
667 let unif_from_stack t1 t2 b metasenv subst =
669 let t1 = NCicReduction.from_stack ~delta:max_int t1 in
670 let t2 = NCicReduction.from_stack ~delta:max_int t2 in
671 unif_machines metasenv subst (put_in_whd t1 t2)
672 with UnificationFailure _ | Uncertain _ when not b ->
675 let rec check_stack l1 l2 r todo =
677 | x1::tl1, x2::tl2, r::tr-> check_stack tl1 tl2 tr ((x1,x2,r)::todo)
678 | x1::tl1, x2::tl2, []-> check_stack tl1 tl2 [] ((x1,x2,true)::todo)
680 NCicReduction.unwind (k1,e1,t1,List.rev l1),
681 NCicReduction.unwind (k2,e2,t2,List.rev l2),
684 let hh1,hh2,todo=check_stack (List.rev s1) (List.rev s2) relevance [] in
686 let metasenv,subst = fo_unif test_eq_only metasenv subst hh1 hh2 in
688 (fun (metasenv,subst) (x1,x2,r) ->
689 unif_from_stack x1 x2 r metasenv subst
690 ) (metasenv,subst) todo
691 with UnificationFailure _ | Uncertain _ when not (norm1 && norm2) ->
692 unif_machines metasenv subst (small_delta_step ~subst m1 m2)
693 (*D*) in outside true; rc with exn -> outside false; raise exn
695 try fo_unif test_eq_only metasenv subst t1 t2
697 | UnificationFailure msg as exn ->
699 unif_machines metasenv subst
700 (put_in_whd (0,[],t1,[]) (0,[],t2,[]))
702 | UnificationFailure _ -> raise (UnificationFailure msg)
703 | Uncertain _ -> raise exn)
704 | Uncertain msg as exn ->
705 match try_hints metasenv subst t1 t2 with
709 unif_machines metasenv subst
710 (put_in_whd (0,[],t1,[]) (0,[],t2,[]))
712 | UnificationFailure _ -> raise (UnificationFailure msg)
713 | Uncertain _ -> raise exn
714 (*D*) in outside true; rc with exn -> outside false; raise exn
716 and delift_type_wrt_terms rdb metasenv subst context t args =
717 let (metasenv, subst), t =
720 ~unify:(fun m s c t1 t2 ->
723 try Some (unify rdb false m s c t1 t2 )
724 with UnificationFailure _ | Uncertain _ -> None
727 metasenv subst context 0 (0,NCic.Ctx (args @
728 List.rev (mk_irl (List.length context)))) t
729 with NCicMetaSubst.MetaSubstFailure _ -> (metasenv, subst), t
735 let unify rdb ?(test_eq_only=false) =
737 unify rdb test_eq_only;;
739 let fix_sorts = fix_sorts true (UnificationFailure (lazy "no sup"));;