* http://cs.unibo.it/helm/.
*)
-exception UnificationFailed;;
-exception Free;;
-exception OccurCheck;;
+open Printf
-type substitution = (int * Cic.term) list
+exception UnificationFailure of string;;
+exception Uncertain of string;;
+exception AssertFailure of string;;
-(*CSC: Hhhmmm. Forse dovremmo spostarla in CicSubstitution dove si trova la *)
-(*CSC: lift? O creare una proofEngineSubstitution? *)
-(* the function delift n m un-lifts a lambda term m of n level of abstractions.
- It returns an exception Free if M contains a free variable in the range 1--n *)
-let delift n =
- let rec deliftaux k =
- let module C = Cic in
- function
- C.Rel m ->
- if m < k then C.Rel m else
- if m < k+n then raise Free
- else C.Rel (m - n)
- | C.Var _ as t -> t
- | C.Meta _ as t -> t
- | C.Sort _ as t -> t
- | C.Implicit as t -> t
- | C.Cast (te,ty) -> C.Cast (deliftaux k te, deliftaux k ty)
- | C.Prod (n,s,t) -> C.Prod (n, deliftaux k s, deliftaux (k+1) t)
- | C.Lambda (n,s,t) -> C.Lambda (n, deliftaux k s, deliftaux (k+1) t)
- | C.LetIn (n,s,t) -> C.LetIn (n, deliftaux k s, deliftaux (k+1) t)
- | C.Appl l -> C.Appl (List.map (deliftaux k) l)
- | C.Const _ as t -> t
- | C.Abst _ as t -> t
- | C.MutInd _ as t -> t
- | C.MutConstruct _ as t -> t
- | C.MutCase (sp,cookingsno,i,outty,t,pl) ->
- C.MutCase (sp, cookingsno, i, deliftaux k outty, deliftaux k t,
- List.map (deliftaux k) pl)
- | C.Fix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, i, ty, bo) -> (name, i, deliftaux k ty, deliftaux (k+len) bo))
- fl
- in
- C.Fix (i, liftedfl)
- | C.CoFix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, ty, bo) -> (name, deliftaux k ty, deliftaux (k+len) bo))
- fl
- in
- C.CoFix (i, liftedfl)
- in
- if n = 0 then
- (function t -> t)
- else
- deliftaux 1
-;;
+let debug_print = prerr_endline
+
+let type_of_aux' metasenv subst context term =
+ try
+ CicMetaSubst.type_of_aux' metasenv subst context term
+ with
+ | CicMetaSubst.MetaSubstFailure msg ->
+ raise (AssertFailure
+ ((sprintf
+ "Type checking error: %s in context\n%s\nand metasenv\n%s.\nException: %s.\nBroken invariant: unification must be invoked only on well typed terms"
+ (CicMetaSubst.ppterm subst term)
+ (CicMetaSubst.ppcontext subst context)
+ (CicMetaSubst.ppmetasenv metasenv subst) msg)))
(* NUOVA UNIFICAZIONE *)
(* A substitution is a (int * Cic.term) list that associates a
metavariable i with its body.
A metaenv is a (int * Cic.term) list that associate a metavariable
i with is type.
- fo_unif_new takes a metasenv, a context,
- two terms t1 and t2 and gives back a new
- substitution which is _NOT_ unwinded. It must be unwinded before
+ fo_unif_new takes a metasenv, a context, two terms t1 and t2 and gives back
+ a new substitution which is _NOT_ unwinded. It must be unwinded before
applying it. *)
-
-let fo_unif_new metasenv context t1 t2 =
- let module C = Cic in
- let module R = CicReduction in
- let module S = CicSubstitution in
- let rec fo_unif_aux subst k t1 t2 =
- match (t1, t2) with
- (C.Meta n, C.Meta m) -> if n == m then subst
- else let subst'=
- let tn = try List.assoc n subst
- with Not_found -> C.Meta n in
- let tm = try List.assoc m subst
- with Not_found -> C.Meta m in
- (match (tn, tm) with
- (C.Meta n, C.Meta m) -> if n==m then subst
- else if n<m
- then (m, C.Meta n)::subst
- else (n, C.Meta m)::subst
- | (C.Meta n, tm) -> (n, tm)::subst
- | (tn, C.Meta m) -> (m, tn)::subst
- | (tn,tm) -> fo_unif_aux subst 0 tn tm) in
- (* unify types first *)
- let tyn = List.assoc n metasenv in
- let tym = List.assoc m metasenv in
- fo_unif_aux subst' 0 tyn tym
- | (C.Meta n, t)
- | (t, C.Meta n) -> (* unify types first *)
- let t' = delift k t in
- let subst' =
- (try fo_unif_aux subst 0 (List.assoc n subst) t'
- with Not_found -> (n, t')::subst) in
- let tyn = List.assoc n metasenv in
- let tyt = CicTypeChecker.type_of_aux' metasenv context t' in
- fo_unif_aux subst' 0 tyn tyt
- | (C.Rel _, _)
- | (_, C.Rel _)
- | (C.Var _, _)
- | (_, C.Var _)
- | (C.Sort _ ,_)
- | (_, C.Sort _)
- | (C.Implicit, _)
- | (_, C.Implicit) -> if R.are_convertible t1 t2 then subst
- else raise UnificationFailed
- | (C.Cast (te,ty), t2) -> fo_unif_aux subst k te t2
- | (t1, C.Cast (te,ty)) -> fo_unif_aux subst k t1 te
- | (C.Prod (_,s1,t1), C.Prod (_,s2,t2)) ->
- let subst' = fo_unif_aux subst k s1 s2 in
- fo_unif_aux subst' (k+1) t1 t2
- | (C.Lambda (_,s1,t1), C.Lambda (_,s2,t2)) ->
- let subst' = fo_unif_aux subst k s1 s2 in
- fo_unif_aux subst' (k+1) t1 t2
- | (C.LetIn (_,s1,t1), t2) -> fo_unif_aux subst k (S.subst s1 t1) t2
- | (t1, C.LetIn (_,s2,t2)) -> fo_unif_aux subst k t1 (S.subst s2 t2)
- | (C.Appl l1, C.Appl l2) ->
- let lr1 = List.rev l1 in
- let lr2 = List.rev l2 in
- let rec fo_unif_l subst = function
- [],_
- | _,[] -> assert false
- | ([h1],[h2]) -> fo_unif_aux subst k h1 h2
- | ([h],l)
- | (l,[h]) -> fo_unif_aux subst k h (C.Appl l)
- | ((h1::l1),(h2::l2)) ->
- let subst' = fo_unif_aux subst k h1 h2 in
- fo_unif_l subst' (l1,l2)
- in
- fo_unif_l subst (lr1, lr2)
- | (C.Const _, _)
- | (_, C.Const _)
- | (C.Abst _, _)
- | (_, C.Abst _)
- | (C.MutInd _, _)
- | (_, C.MutInd _)
- | (C.MutConstruct _, _)
- | (_, C.MutConstruct _) -> if R.are_convertible t1 t2 then subst
- else raise UnificationFailed
- | (C.MutCase (_,_,_,outt1,t1,pl1), C.MutCase (_,_,_,outt2,t2,pl2))->
- let subst' = fo_unif_aux subst k outt1 outt2 in
- let subst'' = fo_unif_aux subst' k t1 t2 in
- List.fold_left2 (function subst -> fo_unif_aux subst k) subst'' pl1 pl2
- | (C.Fix _, _)
- | (_, C.Fix _)
- | (C.CoFix _, _)
- | (_, C.CoFix _) -> if R.are_convertible t1 t2 then subst
- else raise UnificationFailed
- | (_,_) -> raise UnificationFailed
- in fo_unif_aux [] 0 t1 t2;;
-
-(* unwind mgu mark m applies mgu to the term m; mark is an array of integers
-mark.(n) = 0 if the term has not been unwinded, is 2 if it is under uwinding,
-and is 1 if it has been succesfully unwinded. Meeting the value 2 during
-the computation is an error: occur-check *)
-let unwind subst unwinded t =
- let unwinded = ref unwinded in
- let frozen = ref [] in
- let rec um_aux k =
- let module C = Cic in
- let module S = CicSubstitution in
- function
- C.Rel _ as t -> t
- | C.Var _ as t -> t
- | C.Meta i as t ->(try S.lift k (List.assoc i !unwinded)
- with Not_found ->
- if List.mem i !frozen then
- raise OccurCheck
- else
- let saved_frozen = !frozen in
- frozen := i::!frozen ;
- let res =
- try
- let t = List.assoc i subst in
- let t' = um_aux 0 t in
- unwinded := (i,t')::!unwinded ;
- S.lift k t'
- with
- Not_found ->
- (* not constrained variable, i.e. free in subst*)
- C.Meta i
- in
- frozen := saved_frozen ;
- res
- )
- | C.Sort _ as t -> t
- | C.Implicit as t -> t
- | C.Cast (te,ty) -> C.Cast (um_aux k te, um_aux k ty)
- | C.Prod (n,s,t) -> C.Prod (n, um_aux k s, um_aux (k+1) t)
- | C.Lambda (n,s,t) -> C.Lambda (n, um_aux k s, um_aux (k+1) t)
- | C.LetIn (n,s,t) -> C.LetIn (n, um_aux k s, um_aux (k+1) t)
- | C.Appl (he::tl) ->
- let tl' = List.map (um_aux k) tl in
- begin
- match um_aux k he with
- C.Appl l -> C.Appl (l@tl')
- | _ as he' -> C.Appl (he'::tl')
- end
- | C.Appl _ -> assert false
- | C.Const _ as t -> t
- | C.Abst _ as t -> t
- | C.MutInd _ as t -> t
- | C.MutConstruct _ as t -> t
- | C.MutCase (sp,cookingsno,i,outty,t,pl) ->
- C.MutCase (sp, cookingsno, i, um_aux k outty, um_aux k t,
- List.map (um_aux k) pl)
- | C.Fix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, i, ty, bo) -> (name, i, um_aux k ty, um_aux (k+len) bo))
- fl
+let rec fo_unif_subst test_equality_only subst context metasenv t1 t2 =
+ let module C = Cic in
+ let module R = CicMetaSubst in
+ let module S = CicSubstitution in
+ match (t1, t2) with
+ (C.Meta (n,ln), C.Meta (m,lm)) when n=m ->
+ let ok,subst,metasenv =
+ try
+ List.fold_left2
+ (fun (b,subst,metasenv) t1 t2 ->
+ if b then true,subst,metasenv else
+ match t1,t2 with
+ None,_
+ | _,None -> true,subst,metasenv
+ | Some t1', Some t2' ->
+ (* First possibility: restriction *)
+ (* Second possibility: unification *)
+ (* Third possibility: convertibility *)
+ if R.are_convertible subst context t1' t2' then
+ true,subst,metasenv
+ else
+ (try
+ let subst,metasenv =
+ fo_unif_subst
+ test_equality_only subst context metasenv t1' t2'
+ in
+ true,subst,metasenv
+ with
+ Not_found -> false,subst,metasenv)
+ ) (true,subst,metasenv) ln lm
+ with
+ Invalid_argument _ ->
+ raise (UnificationFailure (sprintf
+ "Error trying to unify %s with %s: the lengths of the two local contexts do not match." (CicMetaSubst.ppterm subst t1) (CicMetaSubst.ppterm subst t2)))
in
- C.Fix (i, liftedfl)
- | C.CoFix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, ty, bo) -> (name, um_aux k ty, um_aux (k+len) bo))
- fl
+ if ok then
+ subst,metasenv
+ else
+ raise (UnificationFailure (sprintf
+ "Error trying to unify %s with %s: the algorithm tried to check whether the two substitutions are convertible; if they are not, it tried to unify the two substitutions. No restriction was attempted."
+ (CicMetaSubst.ppterm subst t1) (CicMetaSubst.ppterm subst t2)))
+ | (C.Meta (n,_), C.Meta (m,_)) when n>m ->
+ fo_unif_subst test_equality_only subst context metasenv t2 t1
+ | (C.Meta (n,l), t)
+ | (t, C.Meta (n,l)) ->
+ let swap =
+ match t1,t2 with
+ C.Meta (n,_), C.Meta (m,_) when n < m -> false
+ | _, C.Meta _ -> false
+ | _,_ -> true
in
- C.CoFix (i, liftedfl)
- in
- um_aux 0 t,!unwinded
-;;
-
-(* apply_subst_reducing subst (Some (mtr,reductions_no)) t *)
-(* performs as (apply_subst subst t) until it finds an application of *)
-(* (META [meta_to_reduce]) that, once unwinding is performed, creates *)
-(* a new beta-redex; in this case up to [reductions_no] consecutive *)
-(* beta-reductions are performed. *)
-(* Hint: this function is usually called when [reductions_no] *)
-(* eta-expansions have been performed and the head of the new *)
-(* application has been unified with (META [meta_to_reduce]): *)
-(* during the unwinding the eta-expansions are undone. *)
-
-let apply_subst_reducing subst meta_to_reduce t =
- let unwinded = ref subst in
- let rec um_aux k =
- let module C = Cic in
- let module S = CicSubstitution in
- function
- C.Rel _ as t -> t
- | C.Var _ as t -> t
- | C.Meta i as t ->
- (try
- S.lift k (List.assoc i !unwinded)
+ let lower = fun x y -> if swap then y else x in
+ let upper = fun x y -> if swap then x else y in
+ let fo_unif_subst_ordered
+ test_equality_only subst context metasenv m1 m2 =
+ fo_unif_subst test_equality_only subst context metasenv
+ (lower m1 m2) (upper m1 m2)
+ in
+ let subst'',metasenv' =
+ try
+ let oldt = (List.assoc n subst) in
+ let lifted_oldt = S.lift_meta l oldt in
+ fo_unif_subst_ordered
+ test_equality_only subst context metasenv t lifted_oldt
with Not_found ->
- C.Meta i)
- | C.Sort _ as t -> t
- | C.Implicit as t -> t
- | C.Cast (te,ty) -> C.Cast (um_aux k te, um_aux k ty)
- | C.Prod (n,s,t) -> C.Prod (n, um_aux k s, um_aux (k+1) t)
- | C.Lambda (n,s,t) -> C.Lambda (n, um_aux k s, um_aux (k+1) t)
- | C.LetIn (n,s,t) -> C.LetIn (n, um_aux k s, um_aux (k+1) t)
- | C.Appl (he::tl) ->
- let tl' = List.map (um_aux k) tl in
- let t' =
- match um_aux k he with
- C.Appl l -> C.Appl (l@tl')
- | _ as he' -> C.Appl (he'::tl')
- in
- begin
- match meta_to_reduce with
- Some (mtr,reductions_no) when he = C.Meta mtr ->
- let rec beta_reduce =
- function
- (n,(C.Appl (C.Lambda (_,_,t)::he'::tl'))) when n > 0 ->
- let he'' = CicSubstitution.subst he' t in
- if tl' = [] then
- he''
- else
- beta_reduce (n-1,C.Appl(he''::tl'))
- | (_,t) -> t
- in
- beta_reduce (reductions_no,t')
- | _ -> t'
- end
- | C.Appl _ -> assert false
- | C.Const _ as t -> t
- | C.Abst _ as t -> t
- | C.MutInd _ as t -> t
- | C.MutConstruct _ as t -> t
- | C.MutCase (sp,cookingsno,i,outty,t,pl) ->
- C.MutCase (sp, cookingsno, i, um_aux k outty, um_aux k t,
- List.map (um_aux k) pl)
- | C.Fix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, i, ty, bo) -> (name, i, um_aux k ty, um_aux (k+len) bo))
- fl
+ let t',metasenv',subst' =
+ try
+ CicMetaSubst.delift n subst context metasenv l t
+ with
+ (CicMetaSubst.MetaSubstFailure msg)-> raise(UnificationFailure msg)
+ | (CicMetaSubst.Uncertain msg) -> raise (Uncertain msg)
+ in
+ let t'' =
+ match t' with
+ C.Sort (C.Type u) when not test_equality_only ->
+ let u' = CicUniv.fresh () in
+ let s = C.Sort (C.Type u') in
+ ignore (CicUniv.add_ge (upper u u') (lower u u')) ;
+ s
+ | _ -> t'
+ in
+ (n, t'')::subst', metasenv'
in
- C.Fix (i, liftedfl)
- | C.CoFix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, ty, bo) -> (name, um_aux k ty, um_aux (k+len) bo))
- fl
+ let (_,_,meta_type) = CicUtil.lookup_meta n metasenv' in
+ (try
+ let tyt =
+ type_of_aux' metasenv' subst'' context t
+ in
+ fo_unif_subst
+ test_equality_only
+ subst'' context metasenv' tyt (S.lift_meta l meta_type)
+ with AssertFailure _ ->
+ (* TODO huge hack!!!!
+ * we keep on unifying/refining in the hope that the problem will be
+ * eventually solved. In the meantime we're breaking a big invariant:
+ * the terms that we are unifying are no longer well typed in the
+ * current context (in the worst case we could even diverge)
+ *)
+(*
+prerr_endline "********* FROM NOW ON EVERY REASONABLE INVARIANT IS BROKEN.";
+prerr_endline "********* PROCEED AT YOUR OWN RISK. AND GOOD LUCK." ;
+*)
+ (subst'', metasenv'))
+ | (C.Var (uri1,exp_named_subst1),C.Var (uri2,exp_named_subst2))
+ | (C.Const (uri1,exp_named_subst1),C.Const (uri2,exp_named_subst2)) ->
+ if UriManager.eq uri1 uri2 then
+ fo_unif_subst_exp_named_subst test_equality_only subst context metasenv
+ exp_named_subst1 exp_named_subst2
+ else
+ raise (UnificationFailure (sprintf
+ "Can't unify %s with %s due to different constants"
+ (CicMetaSubst.ppterm subst t1) (CicMetaSubst.ppterm subst t2)))
+ | C.MutInd (uri1,i1,exp_named_subst1),C.MutInd (uri2,i2,exp_named_subst2) ->
+ if UriManager.eq uri1 uri2 && i1 = i2 then
+ fo_unif_subst_exp_named_subst test_equality_only subst context metasenv
+ exp_named_subst1 exp_named_subst2
+ else
+ raise (UnificationFailure (sprintf
+ "Can't unify %s with %s due to different inductive principles"
+ (CicMetaSubst.ppterm subst t1) (CicMetaSubst.ppterm subst t2)))
+ | C.MutConstruct (uri1,i1,j1,exp_named_subst1),
+ C.MutConstruct (uri2,i2,j2,exp_named_subst2) ->
+ if UriManager.eq uri1 uri2 && i1 = i2 && j1 = j2 then
+ fo_unif_subst_exp_named_subst test_equality_only subst context metasenv
+ exp_named_subst1 exp_named_subst2
+ else
+ raise (UnificationFailure (sprintf
+ "Can't unify %s with %s due to different inductive constructors"
+ (CicMetaSubst.ppterm subst t1) (CicMetaSubst.ppterm subst t2)))
+ | (C.Implicit _, _) | (_, C.Implicit _) -> assert false
+ | (C.Cast (te,ty), t2) -> fo_unif_subst test_equality_only
+ subst context metasenv te t2
+ | (t1, C.Cast (te,ty)) -> fo_unif_subst test_equality_only
+ subst context metasenv t1 te
+ | (C.Prod (n1,s1,t1), C.Prod (_,s2,t2)) ->
+ (* TASSI: this is the only case in which we want == *)
+ let subst',metasenv' = fo_unif_subst true
+ subst context metasenv s1 s2 in
+ fo_unif_subst test_equality_only
+ subst' ((Some (n1,(C.Decl s1)))::context) metasenv' t1 t2
+ | (C.Lambda (n1,s1,t1), C.Lambda (_,s2,t2)) ->
+ (* TASSI: ask someone a reason for not putting true here *)
+ let subst',metasenv' = fo_unif_subst test_equality_only
+ subst context metasenv s1 s2 in
+ fo_unif_subst test_equality_only
+ subst' ((Some (n1,(C.Decl s1)))::context) metasenv' t1 t2
+ | (C.LetIn (_,s1,t1), t2)
+ | (t2, C.LetIn (_,s1,t1)) ->
+ fo_unif_subst
+ test_equality_only subst context metasenv t2 (S.subst s1 t1)
+ | (C.Appl l1, C.Appl l2) ->
+ let lr1 = List.rev l1 in
+ let lr2 = List.rev l2 in
+ let rec fo_unif_l test_equality_only subst metasenv =
+ function
+ [],_
+ | _,[] -> assert false
+ | ([h1],[h2]) ->
+ fo_unif_subst test_equality_only subst context metasenv h1 h2
+ | ([h],l)
+ | (l,[h]) ->
+ fo_unif_subst
+ test_equality_only subst context metasenv h (C.Appl (List.rev l))
+ | ((h1::l1),(h2::l2)) ->
+ let subst', metasenv' =
+ fo_unif_subst test_equality_only subst context metasenv h1 h2
+ in
+ fo_unif_l test_equality_only subst' metasenv' (l1,l2)
in
- C.CoFix (i, liftedfl)
- in
- um_aux 0 t
-;;
+ fo_unif_l test_equality_only subst metasenv (lr1, lr2)
+ | (C.MutCase (_,_,outt1,t1',pl1), C.MutCase (_,_,outt2,t2',pl2))->
+ let subst', metasenv' =
+ fo_unif_subst test_equality_only subst context metasenv outt1 outt2 in
+ let subst'',metasenv'' =
+ fo_unif_subst test_equality_only subst' context metasenv' t1' t2' in
+ (try
+ List.fold_left2
+ (function (subst,metasenv) ->
+ fo_unif_subst test_equality_only subst context metasenv
+ ) (subst'',metasenv'') pl1 pl2
+ with
+ Invalid_argument _ ->
+ raise (UnificationFailure (sprintf
+ "Error trying to unify %s with %s: the number of branches is not the same." (CicMetaSubst.ppterm subst t1) (CicMetaSubst.ppterm subst t2))))
+ | (C.Rel _, _) | (_, C.Rel _)
+ | (C.Sort _ ,_) | (_, C.Sort _)
+ | (C.Const _, _) | (_, C.Const _)
+ | (C.MutInd _, _) | (_, C.MutInd _)
+ | (C.MutConstruct _, _) | (_, C.MutConstruct _)
+ | (C.Fix _, _) | (_, C.Fix _)
+ | (C.CoFix _, _) | (_, C.CoFix _) ->
+ if R.are_convertible subst context t1 t2 then
+ subst, metasenv
+ else
+ raise (UnificationFailure (sprintf
+ "Can't unify %s with %s because they are not convertible"
+ (CicMetaSubst.ppterm subst t1) (CicMetaSubst.ppterm subst t2)))
+ | (_,_) ->
+ if R.are_convertible subst context t1 t2 then
+ subst, metasenv
+ else
+ raise (UnificationFailure (sprintf
+ "Can't unify %s with %s because they are not convertible"
+ (CicMetaSubst.ppterm subst t1) (CicMetaSubst.ppterm subst t2)))
-(* UNWIND THE MGU INSIDE THE MGU *)
-let unwind_subst subst =
- List.fold_left
- (fun unwinded (i,_) -> snd (unwind subst unwinded (Cic.Meta i))) [] subst
-;;
+and fo_unif_subst_exp_named_subst test_equality_only subst context metasenv
+ exp_named_subst1 exp_named_subst2
+=
+ try
+ List.fold_left2
+ (fun (subst,metasenv) (uri1,t1) (uri2,t2) ->
+ assert (uri1=uri2) ;
+ fo_unif_subst test_equality_only subst context metasenv t1 t2
+ ) (subst,metasenv) exp_named_subst1 exp_named_subst2
+ with
+ Invalid_argument _ ->
+ let print_ens ens =
+ String.concat " ; "
+ (List.map
+ (fun (uri,t) ->
+ UriManager.string_of_uri uri ^ " := " ^ (CicMetaSubst.ppterm subst t)
+ ) ens)
+ in
+ raise (UnificationFailure (sprintf
+ "Error trying to unify the two explicit named substitutions (local contexts) %s and %s: their lengths is different." (print_ens exp_named_subst1) (print_ens exp_named_subst2)))
-let apply_subst subst t =
- fst (unwind [] subst t)
-;;
+(* A substitution is a (int * Cic.term) list that associates a *)
+(* metavariable i with its body. *)
+(* metasenv is of type Cic.metasenv *)
+(* fo_unif takes a metasenv, a context, two terms t1 and t2 and gives back *)
+(* a new substitution which is already unwinded and ready to be applied and *)
+(* a new metasenv in which some hypothesis in the contexts of the *)
+(* metavariables may have been restricted. *)
+let fo_unif metasenv context t1 t2 =
+ fo_unif_subst false [] context metasenv t1 t2 ;;
-(* A substitution is a (int * Cic.term) list that associates a
- metavariable i with its body.
- A metaenv is a (int * Cic.term) list that associate a metavariable
- i with is type.
- fo_unif takes a metasenv, a context,
- two terms t1 and t2 and gives back a new
- substitution which is already unwinded and ready to be applied. *)
-let fo_unif metasenv context t1 t2 =
- let subst_to_unwind = fo_unif_new metasenv context t1 t2 in
- unwind_subst subst_to_unwind
+let fo_unif_subst subst context metasenv t1 t2 =
+ let enrich_msg msg =
+ sprintf "Unification error unifying %s of type %s with %s of type %s in context\n%s\nand metasenv\n%s\nbecause %s"
+ (CicMetaSubst.ppterm subst t1)
+ (try
+ CicPp.ppterm (type_of_aux' metasenv subst context t1)
+ with _ -> "MALFORMED")
+ (CicMetaSubst.ppterm subst t2)
+ (try
+ CicPp.ppterm (type_of_aux' metasenv subst context t2)
+ with _ -> "MALFORMED")
+ (CicMetaSubst.ppcontext subst context)
+ (CicMetaSubst.ppmetasenv metasenv subst) msg
+ in
+ try
+ fo_unif_subst false subst context metasenv t1 t2
+ with
+ | AssertFailure msg -> raise (AssertFailure (enrich_msg msg))
+ | UnificationFailure msg -> raise (UnificationFailure (enrich_msg msg))
;;
+
projects / helm.git / blobdiff