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 as exn ->
218 pp(lazy("we try to fix the sort\n"^
219 Lazy.force msg^"\n"^NCicPp.ppmetasenv ~subst metasenv));
220 let ft = fix_sorts swap exc_to_be t in
221 pp(lazy("unable to fix the sort"));
222 if ft == t then raise exn;
223 (try ft, NCicTypeChecker.typeof ~subst ~metasenv context ft
224 with NCicTypeChecker.AssertFailure _ -> raise exn)
225 | NCicTypeChecker.TypeCheckerFailure msg ->
226 prerr_endline (Lazy.force msg);
227 prerr_endline (NCicPp.ppterm ~metasenv ~subst ~context t);
228 prerr_endline (ppcontext ~metasenv ~subst context);
229 prerr_endline (ppmetasenv ~subst metasenv);
233 | NCic.Implicit (`Typeof _) ->
234 raise (UnificationFailure(lazy "trying to unify a term with a type"))
236 let lty = NCicSubstitution.subst_meta lc ty in
237 pp (lazy ("On the types: " ^
238 NCicPp.ppterm ~metasenv ~subst ~context lty ^ " === " ^
239 NCicPp.ppterm ~metasenv ~subst ~context ty_t));
241 try unify test_eq_only metasenv subst context lty ty_t
242 with NCicEnvironment.BadConstraint _ as exc ->
243 let ty_t = fix_sorts swap exc_to_be ty_t in
244 try unify test_eq_only metasenv subst context lty ty_t
246 | NCicEnvironment.BadConstraint _
247 | UnificationFailure _ -> raise exc
251 (* viral sortification *)
252 let is_sort metasenv subst context t =
253 match NCicReduction.whd ~subst context t with
255 let tags, _, _ = NCicUtils.lookup_meta i metasenv in
256 has_tag ((=) `IsSort) tags
257 | NCic.Sort _ -> true
260 let rec sortify metasenv subst = function
261 | NCic.Implicit (`Typeof _) -> assert false
262 | NCic.Sort _ as t -> metasenv, subst, t, 0
263 | NCic.Meta (i,_) as t ->
264 let tags, context, ty = NCicUtils.lookup_meta i metasenv in
265 if has_tag ((=) `IsSort) tags then metasenv, subst, t, i
267 let ty = NCicReduction.whd ~subst context ty in
268 let metasenv, subst, ty, _ = sortify metasenv subst ty in
269 let metasenv, j, m, _ =
270 NCicMetaSubst.mk_meta metasenv ~attrs:[`IsSort] [] (`WithType ty)
272 pp(lazy("rimpiazzo " ^ string_of_int i^" con "^string_of_int j));
273 let subst_entry = i, (tags, context, m, ty) in
274 let subst = subst_entry :: subst in
275 let metasenv = List.filter (fun x,_ -> i <> x) metasenv in
276 metasenv, subst, m, j
278 if could_reduce t then raise (Uncertain(lazy "not a sort"))
279 else raise (UnificationFailure(lazy "not a sort"))
281 let metasenv, subst, _, n =
282 if has_tag ((=) `IsSort) tags then
283 let m,s,x,_ = sortify metasenv subst (NCicReduction.whd ~subst context t)
285 else if is_sort metasenv subst context t then
286 sortify metasenv subst (NCic.Meta (n,lc))
288 metasenv, subst, NCic.Rel ~-1,n
290 let tags, ctx, ty = NCicUtils.lookup_meta n metasenv in
294 - Meta sort === t -> check t is sort or sortify
295 - add tag `IsSort and set cc=[] to n and its pile
296 - se gli ancestor non sono sorte o meta... bum...
297 - cambiare in-place menv
298 - geneare meta fresh sorta e dall'alto al basso
299 - Meta _ === Meta sort -> sortify n (i.e. add `IsSort)
301 pp (lazy(string_of_int n ^ " := 111 = "^
302 NCicPp.ppterm ~metasenv ~subst ~context t));
303 let (metasenv, subst), t =
306 ~unify:(fun m s c t1 t2 ->
309 try Some (unify test_eq_only m s c t1 t2 )
310 with UnificationFailure _ | Uncertain _ -> None
313 metasenv subst context n lc t
314 with NCicMetaSubst.Uncertain msg ->
315 pp (lazy ("delift fails: " ^ Lazy.force msg));
316 raise (Uncertain msg)
317 | NCicMetaSubst.MetaSubstFailure msg ->
318 pp (lazy ("delift fails: " ^ Lazy.force msg));
319 raise (UnificationFailure msg)
321 pp (lazy(string_of_int n ^ " := 222 = "^
322 NCicPp.ppterm ~metasenv ~subst ~context:ctx t
323 ^ ppmetasenv ~subst metasenv));
324 (* Unifying the types may have already instantiated n. *)
326 let _, _,oldt,_ = NCicUtils.lookup_subst n subst in
327 let oldt = NCicSubstitution.subst_meta lc oldt in
328 let t = NCicSubstitution.subst_meta lc t in
329 (* conjecture: always fail --> occur check *)
330 unify test_eq_only metasenv subst context oldt t
331 with NCicUtils.Subst_not_found _ ->
332 (* by cumulativity when unify(?,Type_i)
333 * we could ? := Type_j with j <= i... *)
334 let subst = (n, (tags, ctx, t, ty)) :: subst in
335 pp (lazy ("?"^string_of_int n^" := "^NCicPp.ppterm
336 ~metasenv ~subst ~context (NCicSubstitution.subst_meta lc t)));
338 List.filter (fun (m,_) -> not (n = m)) metasenv
341 (*D*) in outside true; rc with exn -> outside false; raise exn
343 and unify rdb test_eq_only metasenv subst context t1 t2 =
344 (*D*) inside 'U'; try let rc =
345 let fo_unif test_eq_only metasenv subst t1 t2 =
346 (*D*) inside 'F'; try let rc =
347 pp (lazy(" " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " ==?== " ^
348 NCicPp.ppterm ~metasenv ~subst ~context t2 ^ ppmetasenv
354 | C.Appl [_], _ | _, C.Appl [_] | C.Appl [], _ | _, C.Appl []
355 | C.Appl (C.Appl _::_), _ | _, C.Appl (C.Appl _::_) ->
356 prerr_endline "Appl [Appl _;_] or Appl [] or Appl [_] invariant";
358 | (C.Sort (C.Type a), C.Sort (C.Type b)) when not test_eq_only ->
359 if NCicEnvironment.universe_leq a b then metasenv, subst
360 else raise (fail_exc metasenv subst context t1 t2)
361 | (C.Sort (C.Type a), C.Sort (C.Type b)) ->
362 if NCicEnvironment.universe_eq a b then metasenv, subst
363 else raise (fail_exc metasenv subst context t1 t2)
364 | (C.Sort C.Prop,C.Sort (C.Type _)) ->
365 if (not test_eq_only) then metasenv, subst
366 else raise (fail_exc metasenv subst context t1 t2)
368 | (C.Lambda (name1,s1,t1), C.Lambda(_,s2,t2))
369 | (C.Prod (name1,s1,t1), C.Prod(_,s2,t2)) ->
370 let metasenv, subst = unify rdb true metasenv subst context s1 s2 in
371 unify rdb test_eq_only metasenv subst ((name1, C.Decl s1)::context) t1 t2
372 | (C.LetIn (name1,ty1,s1,t1), C.LetIn(_,ty2,s2,t2)) ->
373 let metasenv,subst=unify rdb test_eq_only metasenv subst context ty1 ty2 in
374 let metasenv,subst=unify rdb test_eq_only metasenv subst context s1 s2 in
375 let context = (name1, C.Def (s1,ty1))::context in
376 unify rdb test_eq_only metasenv subst context t1 t2
378 | (C.Meta (n1,(s1,l1 as lc1)),C.Meta (n2,(s2,l2 as lc2))) when n1 = n2 ->
380 let l1 = NCicUtils.expand_local_context l1 in
381 let l2 = NCicUtils.expand_local_context l2 in
382 let metasenv, subst, to_restrict, _ =
384 (fun t1 t2 (metasenv, subst, to_restrict, i) ->
386 let metasenv, subst =
387 unify rdb test_eq_only metasenv subst context
388 (NCicSubstitution.lift s1 t1) (NCicSubstitution.lift s2 t2)
390 metasenv, subst, to_restrict, i-1
391 with UnificationFailure _ | Uncertain _ ->
392 metasenv, subst, i::to_restrict, i-1)
393 l1 l2 (metasenv, subst, [], List.length l1)
395 if to_restrict <> [] then
396 let metasenv, subst, _ =
397 NCicMetaSubst.restrict metasenv subst n1 to_restrict
402 | Invalid_argument _ -> assert false
403 | NCicMetaSubst.MetaSubstFailure msg ->
405 let _,_,term,_ = NCicUtils.lookup_subst n1 subst in
406 let term1 = NCicSubstitution.subst_meta lc1 term in
407 let term2 = NCicSubstitution.subst_meta lc2 term in
408 unify rdb test_eq_only metasenv subst context term1 term2
409 with NCicUtils.Subst_not_found _-> raise (UnificationFailure msg))
411 | _, NCic.Meta (n, _) when is_locked n subst ->
412 (let (metasenv, subst), i =
413 match NCicReduction.whd ~subst context t1 with
414 | NCic.Appl (NCic.Meta (i,l)::args) ->
415 let metasenv, subst, lambda_Mj =
416 lambda_intros rdb metasenv subst context t1 args
418 unify rdb test_eq_only metasenv subst context
419 (C.Meta (i,l)) lambda_Mj,
421 | NCic.Meta (i,_) -> (metasenv, subst), i
423 raise (UnificationFailure (lazy "Locked term vs non
424 flexible term; probably not saturated enough yet!"))
426 let t1 = NCicReduction.whd ~subst context t1 in
428 match t1 with NCic.Meta (j,l) -> j, l | _ -> assert false
430 let metasenv, subst =
431 instantiate rdb test_eq_only metasenv subst context j lj t2 true
433 (* We need to remove the out_scope_tags to avoid propagation of
434 them that triggers again the ad-hoc case *)
436 List.map (fun (i,(tag,ctx,bo,ty)) ->
439 (function `InScope | `OutScope _ -> false | _ -> true) tag
445 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
446 let term = eta_reduce subst term in
447 let subst = List.filter (fun (j,_) -> j <> i) subst in
448 metasenv, ((i, (name, ctx, term, ty)) :: subst)
449 with Not_found -> assert false))
451 | C.Meta (n,lc), t ->
453 let _,_,term,_ = NCicUtils.lookup_subst n subst in
454 let term = NCicSubstitution.subst_meta lc term in
455 unify rdb test_eq_only metasenv subst context term t
456 with NCicUtils.Subst_not_found _->
457 instantiate rdb test_eq_only metasenv subst context n lc
458 (NCicReduction.head_beta_reduce ~subst t) false)
460 | t, C.Meta (n,lc) ->
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 t term
465 with NCicUtils.Subst_not_found _->
466 instantiate rdb test_eq_only metasenv subst context n lc
467 (NCicReduction.head_beta_reduce ~subst t) true)
469 | NCic.Appl (NCic.Meta (i,l)::args), _ when List.mem_assoc i subst ->
470 let _,_,term,_ = NCicUtils.lookup_subst i subst in
471 let term = NCicSubstitution.subst_meta l term in
472 unify rdb test_eq_only metasenv subst context
473 (mk_appl ~upto:(List.length args) term args) t2
475 | _, NCic.Appl (NCic.Meta (i,l)::args) when List.mem_assoc i subst ->
476 let _,_,term,_ = NCicUtils.lookup_subst i subst in
477 let term = NCicSubstitution.subst_meta l term in
478 unify rdb test_eq_only metasenv subst context t1
479 (mk_appl ~upto:(List.length args) term args)
481 | NCic.Appl (NCic.Meta (i,_)::_ as l1),
482 NCic.Appl (NCic.Meta (j,_)::_ as l2) when i=j ->
485 (fun (metasenv, subst) t1 t2 ->
486 unify rdb test_eq_only metasenv subst context t1 t2)
487 (metasenv,subst) l1 l2
488 with Invalid_argument _ ->
489 raise (fail_exc metasenv subst context t1 t2))
491 | NCic.Appl (NCic.Meta (i,l)::args), _ ->
492 let metasenv, subst, lambda_Mj =
493 lambda_intros rdb metasenv subst context t1 args
495 let metasenv, subst =
496 unify rdb test_eq_only metasenv subst context
497 (C.Meta (i,l)) lambda_Mj
499 let metasenv, subst =
500 unify rdb test_eq_only metasenv subst context t1 t2
503 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
504 let term = eta_reduce subst term in
505 let subst = List.filter (fun (j,_) -> j <> i) subst in
506 metasenv, ((i, (name, ctx, term, ty)) :: subst)
507 with Not_found -> assert false)
509 | _, NCic.Appl (NCic.Meta (i,l)::args) ->
510 let metasenv, subst, lambda_Mj =
511 lambda_intros rdb metasenv subst context t2 args
513 let metasenv, subst =
514 unify rdb test_eq_only metasenv subst context
515 lambda_Mj (C.Meta (i,l))
517 let metasenv, subst =
518 unify rdb test_eq_only metasenv subst context t1 t2
521 let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
522 let term = eta_reduce subst term in
523 let subst = List.filter (fun (j,_) -> j <> i) subst in
524 metasenv, ((i, (name, ctx, term, ty)) :: subst)
525 with Not_found -> assert false)
527 (* processing this case here we avoid a useless small delta step *)
528 | (C.Appl ((C.Const r1) as _hd1::tl1), C.Appl (C.Const r2::tl2))
530 let relevance = NCicEnvironment.get_relevance r1 in
531 let relevance = match r1 with
532 | Ref.Ref (_,Ref.Con (_,_,lno)) ->
534 try snd (HExtlib.split_nth lno relevance)
537 HExtlib.mk_list false lno @ relevance
540 let metasenv, subst, _ =
543 (fun (metasenv, subst, relevance) t1 t2 ->
545 match relevance with b::tl -> b,tl | _ -> true, [] in
546 let metasenv, subst =
547 try unify rdb test_eq_only metasenv subst context t1 t2
548 with UnificationFailure _ | Uncertain _ when not b ->
551 metasenv, subst, relevance)
552 (metasenv, subst, relevance) tl1 tl2
553 with Invalid_argument _ ->
554 raise (uncert_exc metasenv subst context t1 t2)
558 | (C.Match (Ref.Ref (_,Ref.Ind (_,tyno,_)) as ref1,outtype1,term1,pl1),
559 C.Match (ref2,outtype2,term2,pl2)) ->
560 let _,_,itl,_,_ = NCicEnvironment.get_checked_indtys ref1 in
561 let _,_,ty,_ = List.nth itl tyno in
562 let rec remove_prods ~subst context ty =
563 let ty = NCicReduction.whd ~subst context ty in
566 | C.Prod (name,so,ta) ->
567 remove_prods ~subst ((name,(C.Decl so))::context) ta
571 match remove_prods ~subst [] ty with
572 | C.Sort C.Prop -> true
575 if not (Ref.eq ref1 ref2) then
576 raise (uncert_exc metasenv subst context t1 t2)
578 let metasenv, subst =
579 unify rdb test_eq_only metasenv subst context outtype1 outtype2 in
580 let metasenv, subst =
581 try unify rdb test_eq_only metasenv subst context term1 term2
582 with UnificationFailure _ | Uncertain _ when is_prop ->
587 (fun (metasenv,subst) ->
588 unify rdb test_eq_only metasenv subst context)
589 (metasenv, subst) pl1 pl2
590 with Invalid_argument _ -> assert false)
591 | (C.Implicit _, _) | (_, C.Implicit _) -> assert false
592 | _ when NCicUntrusted.metas_of_term subst context t1 = [] &&
593 NCicUntrusted.metas_of_term subst context t2 = [] ->
594 raise (fail_exc metasenv subst context t1 t2)
595 | _ -> raise (uncert_exc metasenv subst context t1 t2)
596 (*D*) in outside true; rc with exn -> outside false; raise exn
598 let try_hints metasenv subst t1 t2 (* exc*) =
599 (*D*) inside 'H'; try let rc =
601 prerr_endline ("\nProblema:\n" ^
602 NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " =?= " ^
603 NCicPp.ppterm ~metasenv ~subst ~context t2);
606 NCicUnifHint.look_for_hint rdb metasenv subst context t1 t2
608 let rec cand_iter = function
609 | [] -> None (* raise exc *)
610 | (metasenv,(c1,c2),premises)::tl ->
611 pp (lazy ("\nProvo il candidato:\n" ^
615 NCicPp.ppterm ~metasenv ~subst ~context a ^ " =?= " ^
616 NCicPp.ppterm ~metasenv ~subst ~context b) premises) ^
617 "\n-------------------------------------------\n"^
618 NCicPp.ppterm ~metasenv ~subst ~context c1 ^ " = " ^
619 NCicPp.ppterm ~metasenv ~subst ~context c2));
621 (*D*) inside 'K'; try let rc =
623 fo_unif test_eq_only metasenv subst t1 c1 in
625 fo_unif test_eq_only metasenv subst c2 t2 in
628 (fun (metasenv, subst) (x,y) ->
629 unify rdb test_eq_only metasenv subst context x y)
630 (metasenv, subst) premises
632 Some (metasenv, subst)
633 (*D*) in outside true; rc with exn -> outside false; raise exn
635 UnificationFailure _ | Uncertain _ ->
639 (*D*) in outside true; rc with exn -> outside false; raise exn
641 let height_of = function
642 | NCic.Const (Ref.Ref (_,Ref.Def h))
643 | NCic.Const (Ref.Ref (_,Ref.Fix (_,_,h)))
644 | NCic.Appl(NCic.Const(Ref.Ref(_,Ref.Def h))::_)
645 | NCic.Appl(NCic.Const(Ref.Ref(_,Ref.Fix (_,_,h)))::_) -> h
648 let put_in_whd m1 m2 =
649 NCicReduction.reduce_machine ~delta:max_int ~subst context m1,
650 NCicReduction.reduce_machine ~delta:max_int ~subst context m2
652 let small_delta_step ~subst
653 ((_,_,t1,_ as m1, norm1) as x1) ((_,_,t2,_ as m2, norm2) as x2)
655 assert (not (norm1 && norm2));
657 x1,NCicReduction.reduce_machine ~delta:(height_of t2 -1) ~subst context m2
659 NCicReduction.reduce_machine ~delta:(height_of t1 -1) ~subst context m1,x2
661 let h1 = height_of t1 in
662 let h2 = height_of t2 in
663 let delta = if h1 = h2 then max 0 (h1 -1) else min h1 h2 in
664 NCicReduction.reduce_machine ~delta ~subst context m1,
665 NCicReduction.reduce_machine ~delta ~subst context m2
667 let rec unif_machines metasenv subst =
669 | ((k1,e1,t1,s1),norm1 as m1),((k2,e2,t2,s2),norm2 as m2) ->
670 (*D*) inside 'M'; try let rc =
672 NCicPp.ppterm ~metasenv ~subst ~context
673 (NCicReduction.unwind (k1,e1,t1,s1)) ^
675 NCicPp.ppterm ~metasenv ~subst ~context
676 (NCicReduction.unwind (k2,e2,t2,s2))));
677 pp (lazy (string_of_bool norm1 ^ " ?? " ^ string_of_bool norm2));
678 let relevance = [] (* TO BE UNDERSTOOD
680 | C.Const r -> NCicEnvironment.get_relevance r
682 let unif_from_stack t1 t2 b metasenv subst =
684 let t1 = NCicReduction.from_stack ~delta:max_int t1 in
685 let t2 = NCicReduction.from_stack ~delta:max_int t2 in
686 unif_machines metasenv subst (put_in_whd t1 t2)
687 with UnificationFailure _ | Uncertain _ when not b ->
690 let rec check_stack l1 l2 r todo =
692 | x1::tl1, x2::tl2, r::tr-> check_stack tl1 tl2 tr ((x1,x2,r)::todo)
693 | x1::tl1, x2::tl2, []-> check_stack tl1 tl2 [] ((x1,x2,true)::todo)
695 NCicReduction.unwind (k1,e1,t1,List.rev l1),
696 NCicReduction.unwind (k2,e2,t2,List.rev l2),
699 let hh1,hh2,todo=check_stack (List.rev s1) (List.rev s2) relevance [] in
701 let metasenv,subst = fo_unif test_eq_only metasenv subst hh1 hh2 in
703 (fun (metasenv,subst) (x1,x2,r) ->
704 unif_from_stack x1 x2 r metasenv subst
705 ) (metasenv,subst) todo
706 with UnificationFailure _ | Uncertain _ when not (norm1 && norm2) ->
707 unif_machines metasenv subst (small_delta_step ~subst m1 m2)
708 (*D*) in outside true; rc with exn -> outside false; raise exn
710 try fo_unif test_eq_only metasenv subst t1 t2
712 | UnificationFailure msg as exn ->
714 unif_machines metasenv subst
715 (put_in_whd (0,[],t1,[]) (0,[],t2,[]))
717 | UnificationFailure _ -> raise (UnificationFailure msg)
718 | Uncertain _ -> raise exn)
719 | Uncertain msg as exn ->
720 match try_hints metasenv subst t1 t2 with
724 unif_machines metasenv subst
725 (put_in_whd (0,[],t1,[]) (0,[],t2,[]))
727 | UnificationFailure _ -> raise (UnificationFailure msg)
728 | Uncertain _ -> raise exn
729 (*D*) in outside true; rc with exn -> outside false; raise exn
731 and delift_type_wrt_terms rdb metasenv subst context t args =
732 let (metasenv, subst), t =
735 ~unify:(fun m s c t1 t2 ->
738 try Some (unify rdb false m s c t1 t2 )
739 with UnificationFailure _ | Uncertain _ -> None
742 metasenv subst context 0 (0,NCic.Ctx (args @
743 List.rev (mk_irl (List.length context)))) t
744 with NCicMetaSubst.MetaSubstFailure _ -> (metasenv, subst), t
750 let unify rdb ?(test_eq_only=false) =
752 unify rdb test_eq_only;;
754 let fix_sorts = fix_sorts true (UnificationFailure (lazy "no sup"));;