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;;
19 ref (fun _ ?localise _ _ _ _ _ -> ignore localise; assert false);;
20 let set_refiner_typeof f = refiner_typeof := f
23 let (===) x y = Pervasives.compare x y = 0 ;;
25 let uncert_exc metasenv subst context t1 t2 =
27 "Can't unify " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^
28 " with " ^ NCicPp.ppterm ~metasenv ~subst ~context t2))
31 let fail_exc metasenv subst context t1 t2 =
32 UnificationFailure (lazy (
33 "Can't unify " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^
34 " with " ^ NCicPp.ppterm ~metasenv ~subst ~context t2));
37 let mk_appl ~upto hd tl =
38 NCicReduction.head_beta_reduce ~upto
40 | NCic.Appl l -> NCic.Appl (l@tl)
41 | _ -> NCic.Appl (hd :: tl))
44 exception WrongShape;;
46 let eta_reduce subst t =
47 let delift_if_not_occur body =
49 Some (NCicSubstitution.psubst ~avoid_beta_redexes:true
50 (fun () -> raise WrongShape) [()] body)
51 with WrongShape -> None
53 let rec eat_lambdas ctx = function
54 | NCic.Lambda (name, src, tgt) ->
55 eat_lambdas ((name, src) :: ctx) tgt
56 | NCic.Meta (i,lc) as t->
58 let _,_,t,_ = NCicUtils.lookup_subst i subst in
59 let t = NCicSubstitution.subst_meta lc t in
61 with Not_found -> ctx, t)
64 let context_body = eat_lambdas [] t in
65 let rec aux = function
67 | (name, src)::ctx, (NCic.Appl (hd::[NCic.Rel 1]) as bo) ->
68 (match delift_if_not_occur hd with
69 | None -> aux (ctx,NCic.Lambda(name,src, bo))
70 | Some bo -> aux (ctx,bo))
71 | (name, src)::ctx, (NCic.Appl args as bo)
72 when HExtlib.list_last args = NCic.Rel 1 ->
73 let args, _ = HExtlib.split_nth (List.length args - 1) args in
74 (match delift_if_not_occur (NCic.Appl args) with
75 | None -> aux (ctx,NCic.Lambda(name,src, bo))
76 | Some bo -> aux (ctx,bo))
77 | (name, src) :: ctx, t ->
78 aux (ctx,NCic.Lambda(name,src, t))
84 module Ref = NReference;;
87 let inside c = indent := !indent ^ String.make 1 c;;
90 indent := String.sub !indent 0 (String.length !indent -1)
92 Invalid_argument _ -> indent := "??"; ()
96 prerr_endline (Printf.sprintf "%-20s" !indent ^ " " ^ Lazy.force s)
99 let ppcontext = NCicPp.ppcontext;;
100 let ppmetasenv = NCicPp.ppmetasenv;;
102 let ppcontext ~metasenv:_metasenv ~subst:_subst _context = "...";;
103 let ppmetasenv ~subst:_subst _metasenv = "...";;
107 let fix_sorts swap metasenv subst context meta t =
108 let rec aux () = function
109 | NCic.Sort (NCic.Type u) as orig ->
111 match NCicEnvironment.sup u with
112 | None -> prerr_endline "no sup for" ;
113 raise (fail_exc metasenv subst context meta t)
114 | Some u1 -> if u = u1 then orig else NCic.Sort (NCic.Type u1)
116 NCic.Sort (NCic.Type (
117 match NCicEnvironment.sup NCicEnvironment.type0 with
119 | _ -> assert false))
120 | NCic.Meta _ as orig -> orig
121 | t -> NCicUtils.map (fun _ _ -> ()) () aux t
126 let is_locked n subst =
128 match NCicUtils.lookup_subst n subst with
129 | Some tag, _,_,_ when NCicMetaSubst.is_out_scope_tag tag -> true
131 with NCicUtils.Subst_not_found _ -> false
137 | n -> NCic.Rel n :: mk_irl (n-1)
140 let rec lambda_intros rdb metasenv subst context t args =
141 let tty = NCicTypeChecker.typeof ~metasenv ~subst context t in
144 (fun arg -> arg, NCicTypeChecker.typeof ~metasenv ~subst context arg) args in
145 let context_of_args = context in
146 let mk_appl = function [] -> assert false | [t] -> t | l -> NCic.Appl l in
147 let rec mk_lambda metasenv subst context n processed_args = function
149 let metasenv, _, bo, _ =
150 NCicMetaSubst.mk_meta metasenv context
151 (`WithType (NCicSubstitution.lift n tty))
155 let name = "HBeta"^string_of_int n in
156 let metasenv,_,instance,_ =
157 NCicMetaSubst.mk_meta metasenv context_of_args `Term in
158 let meta_applied = mk_appl (instance::List.rev processed_args) in
159 let metasenv,subst,_,_ =
160 !refiner_typeof ((rdb :> NRstatus.status)#set_coerc_db NCicCoercion.empty_db) metasenv subst context_of_args meta_applied None
163 unify rdb true metasenv subst context_of_args meta_applied ty in
164 let telescopic_ty = NCicSubstitution.lift n instance in
166 mk_appl (telescopic_ty :: mk_irl (List.length processed_args)) in
167 let metasenv, subst, bo =
168 mk_lambda metasenv subst ((name,NCic.Decl telescopic_ty)::context) (n+1)
169 (arg::processed_args) tail
171 metasenv, subst, NCic.Lambda (name, telescopic_ty, bo)
173 mk_lambda metasenv subst context 0 [] argsty
175 and instantiate rdb test_eq_only metasenv subst context n lc t swap =
176 (*D*) inside 'I'; try let rc =
177 pp (lazy(string_of_int n ^ " :=?= "^
178 NCicPp.ppterm ~metasenv ~subst ~context t));
179 let unify test_eq_only m s c t1 t2 =
180 if swap then unify rdb test_eq_only m s c t2 t1
181 else unify rdb test_eq_only m s c t1 t2
183 let name, ctx, ty = NCicUtils.lookup_meta n metasenv in
184 let metasenv, subst, t =
186 | NCic.Implicit (`Typeof _) ->
188 (* fix_sorts swap metasenv subst context (NCic.Meta(n,lc)) t *)
191 "typeof: " ^ NCicPp.ppterm ~metasenv ~subst ~context t ^ "\nctx:\n"^
192 ppcontext ~metasenv ~subst context ^ "\nmenv:\n"^
193 ppmetasenv ~subst metasenv));
195 try t, NCicTypeChecker.typeof ~subst ~metasenv context t
197 | NCicTypeChecker.AssertFailure msg ->
198 (pp (lazy "fine typeof (fallimento)");
199 let ft=fix_sorts swap metasenv subst context (NCic.Meta (n,lc)) t in
201 (prerr_endline ( ("ILLTYPED: " ^
202 NCicPp.ppterm ~metasenv ~subst ~context t
203 ^ "\nBECAUSE:" ^ Lazy.force msg ^ "\nCONTEXT:\n" ^
204 ppcontext ~metasenv ~subst context ^ "\nMENV:\n" ^
205 ppmetasenv ~subst metasenv
210 pp (lazy ("typeof: " ^
211 NCicPp.ppterm ~metasenv ~subst ~context ft));
212 ft, NCicTypeChecker.typeof ~subst ~metasenv context ft
213 with NCicTypeChecker.AssertFailure _ ->
215 | NCicTypeChecker.TypeCheckerFailure msg ->
216 prerr_endline (Lazy.force msg);
219 let lty = NCicSubstitution.subst_meta lc ty in
222 raise (UnificationFailure
223 (lazy "trying to unify a term with a type"))
225 pp (lazy ("On the types: " ^
226 NCicPp.ppterm ~metasenv ~subst ~context:ctx ty ^ " ~~~ " ^
227 NCicPp.ppterm ~metasenv ~subst ~context lty ^ " === "
228 ^ NCicPp.ppterm ~metasenv ~subst ~context ty_t));
230 unify test_eq_only metasenv subst context lty ty_t in
233 pp (lazy(string_of_int n ^ " := 111 = "^
234 NCicPp.ppterm ~metasenv ~subst ~context t));
235 let (metasenv, subst), t =
238 ~unify:(fun m s c t1 t2 ->
241 try Some (unify test_eq_only m s c t1 t2 )
242 with UnificationFailure _ | Uncertain _ -> None
245 metasenv subst context n lc t
246 with NCicMetaSubst.Uncertain msg ->
247 pp (lazy ("delift fails: " ^ Lazy.force msg));
248 raise (Uncertain msg)
249 | NCicMetaSubst.MetaSubstFailure msg ->
250 pp (lazy ("delift fails: " ^ Lazy.force msg));
251 raise (UnificationFailure msg)
253 pp (lazy(string_of_int n ^ " := 222 = "^
254 NCicPp.ppterm ~metasenv ~subst ~context:ctx t
255 ^ "\n" ^ ppmetasenv ~subst metasenv));
256 (* Unifying the types may have already instantiated n. *)
258 let _, _,oldt,_ = NCicUtils.lookup_subst n subst in
259 let oldt = NCicSubstitution.subst_meta lc oldt in
260 let t = NCicSubstitution.subst_meta lc t in
261 (* conjecture: always fail --> occur check *)
262 unify test_eq_only metasenv subst context oldt t
263 with NCicUtils.Subst_not_found _ ->
264 (* by cumulativity when unify(?,Type_i)
265 * we could ? := Type_j with j <= i... *)
266 let subst = (n, (name, ctx, t, ty)) :: subst in
267 pp (lazy ("?"^string_of_int n^" := "^NCicPp.ppterm
268 ~metasenv ~subst ~context (NCicSubstitution.subst_meta lc t)));
270 List.filter (fun (m,_) -> not (n = m)) metasenv
273 (*D*) in outside(); rc with exn -> outside (); raise exn
275 and unify rdb test_eq_only metasenv subst context t1 t2 =
276 (*D*) inside 'U'; try let rc =
277 let fo_unif test_eq_only metasenv subst t1 t2 =
278 (*D*) inside 'F'; try let rc =
279 pp (lazy(" " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " ==?== " ^
280 NCicPp.ppterm ~metasenv ~subst ~context t2 ^ "\n" ^ ppmetasenv
286 | C.Appl [_], _ | _, C.Appl [_] | C.Appl [], _ | _, C.Appl []
287 | C.Appl (C.Appl _::_), _ | _, C.Appl (C.Appl _::_) ->
288 prerr_endline "Appl [Appl _;_] or Appl [] or Appl [_] invariant";
290 | (C.Sort (C.Type a), C.Sort (C.Type b)) when not test_eq_only ->
291 if NCicEnvironment.universe_leq a b then metasenv, subst
292 else raise (fail_exc metasenv subst context t1 t2)
293 | (C.Sort (C.Type a), C.Sort (C.Type b)) ->
294 if NCicEnvironment.universe_eq a b then metasenv, subst
295 else raise (fail_exc metasenv subst context t1 t2)
296 | (C.Sort C.Prop,C.Sort (C.Type _)) ->
297 if (not test_eq_only) then metasenv, subst
298 else raise (fail_exc metasenv subst context t1 t2)
300 | (C.Lambda (name1,s1,t1), C.Lambda(_,s2,t2))
301 | (C.Prod (name1,s1,t1), C.Prod(_,s2,t2)) ->
302 let metasenv, subst = unify rdb true metasenv subst context s1 s2 in
303 unify rdb test_eq_only metasenv subst ((name1, C.Decl s1)::context) t1 t2
304 | (C.LetIn (name1,ty1,s1,t1), C.LetIn(_,ty2,s2,t2)) ->
305 let metasenv,subst=unify rdb test_eq_only metasenv subst context ty1 ty2 in
306 let metasenv,subst=unify rdb test_eq_only metasenv subst context s1 s2 in
307 let context = (name1, C.Def (s1,ty1))::context in
308 unify rdb test_eq_only metasenv subst context t1 t2
310 | (C.Meta (n1,(s1,l1 as lc1)),C.Meta (n2,(s2,l2 as lc2))) when n1 = n2 ->
312 let l1 = NCicUtils.expand_local_context l1 in
313 let l2 = NCicUtils.expand_local_context l2 in
314 let metasenv, subst, to_restrict, _ =
316 (fun t1 t2 (metasenv, subst, to_restrict, i) ->
318 let metasenv, subst =
319 unify rdb test_eq_only metasenv subst context
320 (NCicSubstitution.lift s1 t1) (NCicSubstitution.lift s2 t2)
322 metasenv, subst, to_restrict, i-1
323 with UnificationFailure _ | Uncertain _ ->
324 metasenv, subst, i::to_restrict, i-1)
325 l1 l2 (metasenv, subst, [], List.length l1)
327 if to_restrict <> [] then
328 let metasenv, subst, _ =
329 NCicMetaSubst.restrict metasenv subst n1 to_restrict
334 | Invalid_argument _ -> assert false
335 | NCicMetaSubst.MetaSubstFailure msg ->
337 let _,_,term,_ = NCicUtils.lookup_subst n1 subst in
338 let term1 = NCicSubstitution.subst_meta lc1 term in
339 let term2 = NCicSubstitution.subst_meta lc2 term in
340 unify rdb test_eq_only metasenv subst context term1 term2
341 with NCicUtils.Subst_not_found _-> raise (UnificationFailure msg))
343 | _, NCic.Meta (n, _) when is_locked n subst ->
344 (let (metasenv, subst), i =
345 match NCicReduction.whd ~subst context t1 with
346 | NCic.Appl (NCic.Meta (i,l)::args) when
347 not (NCicMetaSubst.flexible subst args)
349 let metasenv, subst, lambda_Mj =
350 lambda_intros rdb metasenv subst context t1 args
352 unify rdb test_eq_only metasenv subst context
353 (C.Meta (i,l)) lambda_Mj,
355 | NCic.Meta (i,_) -> (metasenv, subst), i
358 let t1 = NCicReduction.whd ~subst context t1 in
360 match t1 with NCic.Meta (j,l) -> j, l | _ -> assert false
362 let metasenv, subst =
363 instantiate rdb test_eq_only metasenv subst context j lj t2 true
365 (* We need to remove the out_scope_tags to avoid propagation of
366 them that triggers again the ad-hoc case *)
368 List.map (fun (i,(tag,ctx,bo,ty)) ->
372 tag = NCicMetaSubst.in_scope_tag
373 || NCicMetaSubst.is_out_scope_tag tag -> None
380 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
381 let term = eta_reduce subst term in
382 let subst = List.filter (fun (j,_) -> j <> i) subst in
383 metasenv, ((i, (name, ctx, term, ty)) :: subst)
384 with Not_found -> assert false))
386 | C.Meta (n,lc), t ->
388 let _,_,term,_ = NCicUtils.lookup_subst n subst in
389 let term = NCicSubstitution.subst_meta lc term in
390 unify rdb test_eq_only metasenv subst context term t
391 with NCicUtils.Subst_not_found _->
392 instantiate rdb test_eq_only metasenv subst context n lc
393 (NCicReduction.head_beta_reduce ~subst t) false)
395 | t, C.Meta (n,lc) ->
397 let _,_,term,_ = NCicUtils.lookup_subst n subst in
398 let term = NCicSubstitution.subst_meta lc term in
399 unify rdb test_eq_only metasenv subst context t term
400 with NCicUtils.Subst_not_found _->
401 instantiate rdb test_eq_only metasenv subst context n lc
402 (NCicReduction.head_beta_reduce ~subst t) true)
404 | NCic.Appl (NCic.Meta (i,l)::args), _ when List.mem_assoc i subst ->
405 let _,_,term,_ = NCicUtils.lookup_subst i subst in
406 let term = NCicSubstitution.subst_meta l term in
407 unify rdb test_eq_only metasenv subst context
408 (mk_appl ~upto:(List.length args) term args) t2
410 | _, NCic.Appl (NCic.Meta (i,l)::args) when List.mem_assoc i subst ->
411 let _,_,term,_ = NCicUtils.lookup_subst i subst in
412 let term = NCicSubstitution.subst_meta l term in
413 unify rdb test_eq_only metasenv subst context t1
414 (mk_appl ~upto:(List.length args) term args)
416 | NCic.Appl (NCic.Meta (i,_)::_ as l1),
417 NCic.Appl (NCic.Meta (j,_)::_ as l2) when i=j ->
420 (fun (metasenv, subst) t1 t2 ->
421 unify rdb test_eq_only metasenv subst context t1 t2)
422 (metasenv,subst) l1 l2
423 with Invalid_argument _ ->
424 raise (fail_exc metasenv subst context t1 t2))
426 | NCic.Appl (NCic.Meta (i,l)::args), _ when
427 not (NCicMetaSubst.flexible subst args) ->
428 (* we verify that none of the args is a Meta,
429 since beta expanding w.r.t a metavariable makes no sense *)
430 let metasenv, subst, lambda_Mj =
431 lambda_intros rdb metasenv subst context t1 args
433 let metasenv, subst =
434 unify rdb test_eq_only metasenv subst context
435 (C.Meta (i,l)) lambda_Mj
437 let metasenv, subst =
438 unify rdb test_eq_only metasenv subst context t1 t2
441 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
442 let term = eta_reduce subst term in
443 let subst = List.filter (fun (j,_) -> j <> i) subst in
444 metasenv, ((i, (name, ctx, term, ty)) :: subst)
445 with Not_found -> assert false)
447 | _, NCic.Appl (NCic.Meta (i,l)::args) when
448 not(NCicMetaSubst.flexible subst args) ->
449 let metasenv, subst, lambda_Mj =
450 lambda_intros rdb metasenv subst context t2 args
452 let metasenv, subst =
453 unify rdb test_eq_only metasenv subst context
454 lambda_Mj (C.Meta (i,l))
456 let metasenv, subst =
457 unify rdb test_eq_only metasenv subst context t1 t2
460 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
461 let term = eta_reduce subst term in
462 let subst = List.filter (fun (j,_) -> j <> i) subst in
463 metasenv, ((i, (name, ctx, term, ty)) :: subst)
464 with Not_found -> assert false)
466 (* processing this case here we avoid a useless small delta step *)
467 | (C.Appl ((C.Const r1) as _hd1::tl1), C.Appl (C.Const r2::tl2))
469 let relevance = NCicEnvironment.get_relevance r1 in
470 let relevance = match r1 with
471 | Ref.Ref (_,Ref.Con (_,_,lno)) ->
473 try snd (HExtlib.split_nth lno relevance)
476 HExtlib.mk_list false lno @ relevance
479 let metasenv, subst, _ =
482 (fun (metasenv, subst, relevance) t1 t2 ->
484 match relevance with b::tl -> b,tl | _ -> true, [] in
485 let metasenv, subst =
486 try unify rdb test_eq_only metasenv subst context t1 t2
487 with UnificationFailure _ | Uncertain _ when not b ->
490 metasenv, subst, relevance)
491 (metasenv, subst, relevance) tl1 tl2
492 with Invalid_argument _ ->
493 raise (uncert_exc metasenv subst context t1 t2)
497 | (C.Match (Ref.Ref (_,Ref.Ind (_,tyno,_)) as ref1,outtype1,term1,pl1),
498 C.Match (ref2,outtype2,term2,pl2)) ->
499 let _,_,itl,_,_ = NCicEnvironment.get_checked_indtys ref1 in
500 let _,_,ty,_ = List.nth itl tyno in
501 let rec remove_prods ~subst context ty =
502 let ty = NCicReduction.whd ~subst context ty in
505 | C.Prod (name,so,ta) ->
506 remove_prods ~subst ((name,(C.Decl so))::context) ta
510 match remove_prods ~subst [] ty with
511 | C.Sort C.Prop -> true
514 if not (Ref.eq ref1 ref2) then
515 raise (uncert_exc metasenv subst context t1 t2)
517 let metasenv, subst =
518 unify rdb test_eq_only metasenv subst context outtype1 outtype2 in
519 let metasenv, subst =
520 try unify rdb test_eq_only metasenv subst context term1 term2
521 with UnificationFailure _ | Uncertain _ when is_prop ->
526 (fun (metasenv,subst) ->
527 unify rdb test_eq_only metasenv subst context)
528 (metasenv, subst) pl1 pl2
529 with Invalid_argument _ ->
530 raise (uncert_exc metasenv subst context t1 t2))
531 | (C.Implicit _, _) | (_, C.Implicit _) -> assert false
532 | _ when NCicUntrusted.metas_of_term subst context t1 = [] &&
533 NCicUntrusted.metas_of_term subst context t2 = [] ->
534 raise (fail_exc metasenv subst context t1 t2)
535 | _ -> raise (uncert_exc metasenv subst context t1 t2)
536 (*D*) in outside(); rc with exn -> outside (); raise exn
538 let try_hints metasenv subst t1 t2 (* exc*) =
540 prerr_endline ("\nProblema:\n" ^
541 NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " =?= " ^
542 NCicPp.ppterm ~metasenv ~subst ~context t2);
545 NCicUnifHint.look_for_hint rdb metasenv subst context t1 t2
547 let rec cand_iter = function
548 | [] -> None (* raise exc *)
549 | (metasenv,(c1,c2),premises)::tl ->
551 prerr_endline ("\nProvo il candidato:\n" ^
555 NCicPp.ppterm ~metasenv ~subst ~context a ^ " =?= " ^
556 NCicPp.ppterm ~metasenv ~subst ~context b) premises) ^
557 "\n-------------------------------------------\n"^
558 NCicPp.ppterm ~metasenv ~subst ~context c1 ^ " = " ^
559 NCicPp.ppterm ~metasenv ~subst ~context c2);
563 fo_unif test_eq_only metasenv subst t1 c1 in
565 fo_unif test_eq_only metasenv subst c2 t2 in
568 (fun (metasenv, subst) (x,y) ->
569 unify rdb test_eq_only metasenv subst context x y)
570 (metasenv, subst) premises
572 Some (metasenv, subst)
574 UnificationFailure _ | Uncertain _ ->
579 let height_of = function
580 | NCic.Const (Ref.Ref (_,Ref.Def h))
581 | NCic.Const (Ref.Ref (_,Ref.Fix (_,_,h)))
582 | NCic.Appl(NCic.Const(Ref.Ref(_,Ref.Def h))::_)
583 | NCic.Appl(NCic.Const(Ref.Ref(_,Ref.Fix (_,_,h)))::_) -> h
586 let put_in_whd m1 m2 =
587 NCicReduction.reduce_machine ~delta:max_int ~subst context m1,
588 NCicReduction.reduce_machine ~delta:max_int ~subst context m2
590 let small_delta_step ~subst
591 ((_,_,t1,_ as m1, norm1) as x1) ((_,_,t2,_ as m2, norm2) as x2)
593 assert (not (norm1 && norm2));
595 x1,NCicReduction.reduce_machine ~delta:(height_of t2 -1) ~subst context m2
597 NCicReduction.reduce_machine ~delta:(height_of t1 -1) ~subst context m1,x2
599 let h1 = height_of t1 in
600 let h2 = height_of t2 in
601 let delta = if h1 = h2 then max 0 (h1 -1) else min h1 h2 in
602 NCicReduction.reduce_machine ~delta ~subst context m1,
603 NCicReduction.reduce_machine ~delta ~subst context m2
605 let rec unif_machines metasenv subst =
607 | ((k1,e1,t1,s1),norm1 as m1),((k2,e2,t2,s2),norm2 as m2) ->
608 (*D*) inside 'M'; try let rc =
610 NCicPp.ppterm ~metasenv ~subst ~context
611 (NCicReduction.unwind (k1,e1,t1,s1)) ^
613 NCicPp.ppterm ~metasenv ~subst ~context
614 (NCicReduction.unwind (k2,e2,t2,s2))));
615 pp (lazy (string_of_bool norm1 ^ " ?? " ^ string_of_bool norm2));
616 let relevance = [] (* TO BE UNDERSTOOD
618 | C.Const r -> NCicEnvironment.get_relevance r
620 let unif_from_stack t1 t2 b metasenv subst =
622 let t1 = NCicReduction.from_stack t1 in
623 let t2 = NCicReduction.from_stack t2 in
624 unif_machines metasenv subst (put_in_whd t1 t2)
625 with UnificationFailure _ | Uncertain _ when not b ->
628 let rec check_stack l1 l2 r todo =
630 | x1::tl1, x2::tl2, r::tr-> check_stack tl1 tl2 tr ((x1,x2,r)::todo)
631 | x1::tl1, x2::tl2, []-> check_stack tl1 tl2 [] ((x1,x2,true)::todo)
633 NCicReduction.unwind (k1,e1,t1,List.rev l1),
634 NCicReduction.unwind (k2,e2,t2,List.rev l2),
637 let hh1,hh2,todo=check_stack (List.rev s1) (List.rev s2) relevance [] in
639 let metasenv,subst = fo_unif test_eq_only metasenv subst hh1 hh2 in
641 (fun (metasenv,subst) (x1,x2,r) ->
642 unif_from_stack x1 x2 r metasenv subst
643 ) (metasenv,subst) todo
644 with UnificationFailure _ | Uncertain _ when not (norm1 && norm2) ->
645 unif_machines metasenv subst (small_delta_step ~subst m1 m2)
646 (*D*) in outside(); rc with exn -> outside (); raise exn
648 try fo_unif test_eq_only metasenv subst t1 t2
650 | UnificationFailure msg as exn ->
652 unif_machines metasenv subst
653 (put_in_whd (0,[],t1,[]) (0,[],t2,[]))
655 | UnificationFailure _ -> raise (UnificationFailure msg)
656 | Uncertain _ -> raise exn)
657 | Uncertain msg as exn ->
658 match try_hints metasenv subst t1 t2 with
662 unif_machines metasenv subst
663 (put_in_whd (0,[],t1,[]) (0,[],t2,[]))
665 | UnificationFailure _ -> raise (UnificationFailure msg)
666 | Uncertain _ -> raise exn
667 (*D*) in outside(); rc with exn -> outside (); raise exn
670 let unify rdb ?(test_eq_only=false) =
672 unify rdb test_eq_only;;