" with " ^ NCicPp.ppterm ~metasenv ~subst ~context t2))
;;
-let unify metasenv subst context t1 t2 =
+let mk_appl hd tl =
+ match hd with
+ | NCic.Appl l -> NCic.Appl (l@tl)
+ | _ -> NCic.Appl (hd :: tl)
+;;
+
+let flexible l =
+ List.exists
+ (function
+ | NCic.Meta _
+ | NCic.Appl (NCic.Meta _::_) -> true
+ | _ -> false) l
+;;
+
+exception WrongShape;;
+
+let eta_reduce =
+ let delift_if_not_occur body orig =
+ try
+ NCicSubstitution.psubst ~avoid_beta_redexes:true
+ (fun () -> raise WrongShape) [()] body
+ with WrongShape -> orig
+ in
+ function
+ | NCic.Lambda(name, src, NCic.Appl [hd; NCic.Rel 1]) as orig ->
+ delift_if_not_occur hd orig
+ | NCic.Lambda(name, src, NCic.Appl (hd :: l)) as orig
+ when HExtlib.list_last l = NCic.Rel 1 ->
+ let body =
+ let args, _ = Hextlib.split_nth (List.length l - 1) l in
+ NCic.Appl (hd::args)
+ in
+ delift_if_not_occur body orig
+ | t -> t
+;;
+
+let rec beta_expand num test_eq_only swap metasenv subst context t arg =
+ let rec aux (n,context,test_eq_only as k) (metasenv, subst as acc) t' =
+ try
+ let metasenv, subst =
+ unify test_eq_only metasenv subst context
+ (NCicSubstitution.lift n arg) t'
+ in
+ (metasenv, subst), C.Rel (1 + n)
+ with Uncertain _ | UnificationFailure _ ->
+ match t' with
+ | NCic.Rel m orig ->
+ (metasenv, subst), if m <= n then orig else NCic.Rel (m+1)
+ (* andrea: in general, beta_expand can create badly typed
+ terms. This happens quite seldom in practice, UNLESS we
+ iterate on the local context. For this reason, we renounce
+ to iterate and just lift *)
+ | NCic.Meta (i,(shift,lc)) ->
+ (metasenv,subst), NCic.Meta (i,(shift+1,lc))
+ | NCic.Prod (name, src, tgt) as orig ->
+ let (metasenv, subst), src1 = aux (n,context,true) acc src in
+ let k = n+1, (name, NCic.Decl src) :: context, test_eq_only in
+ let (metasenv,subst), tgt1 = aux k (metasenv, subst) tgt in
+ if src == src1 && tgt == tgt1 then orig else
+ NCic.Prod (name, src1, tgt1)
+ | t ->
+ NCicUntrusted.map_term_fold_a
+ (fun e (n,ctx) -> n+1,e::ctx) k aux acc t
+
+ in
+ let argty = NCicTypeChecker.typeof ~metasenv ~subst context arg in
+ let fresh_name = "Hbeta" ^ string_of_int num in
+ let (metasenv,subst,_), t1 =
+ aux (0, context, test_eq_only) (metasenv, subst) t in
+ let t2 = eta_reduce (C.Lambda (fresh_name,argty,t1)) in
+ try
+ ignore(NCicTypeChecker.typeof ~metasenv ~subst context t2);
+ metasenv, subst, t2
+ with NCicTypeChecker.TypeCheckerFailure _ ->
+ NCic.Lambda ("_", argty, NCicSubstitution.lift 1 arg)
+
+and beta_expand_many test_equality_only metasenv subst context t args ugraph =
+ let _, subst, metasenv, hd =
+ List.fold_right
+ (fun arg (num,subst,metasenv,t) ->
+ let subst, metasenv, t =
+ beta_expand num test_equality_only metasenv subst context t arg
+ in
+ num+1,subst,metasenv,t)
+ args (1,subst,metasenv,t)
+ in
+ metasenv, subst, hd
+
+and instantiate test_eq_only metasenv subst context n lc t swap =
+ let unif m s c t1 t2 =
+ if swap then unify m s c t2 t1 else unify m s c t1 t2
+ in
+ let ty_t =
+ try NCicTypeChecker.typeof ~subst ~metasenv context t
+ with NCicTypeChecker.TypeCheckerFailure _ -> assert false
+ in
+ let name, ctx, ty = NCicUtils.lookup_meta n metasenv in
+ let ty = NCicSubstitution.subst_meta lc ty in
+ let metasenv, subst = unify metasenv susbt context ty ty_t in
+ let (metasenv, subst), t =
+ NCicMetaSubst.delift metasenv subst context n lc t
+ in
+ (* Unifying the types may have already instantiated n. *)
+ try
+ let _, _,oldt,_ = CicUtil.lookup_subst n subst in
+ let oldt = NCicSubstitution.subst_meta lc oldt in
+ (* conjecture: always fail --> occur check *)
+ unify test_eq_only metasenv subst context oldt t
+ with CicUtil.Subst_not_found _ ->
+ (* by cumulativity when unify(?,Type_i)
+ * we could ? := Type_j with j <= i... *)
+ let subst = (n, (name, ctx, t, ty)) :: subst in
+ let metasenv =
+ List.filter (fun (m,_) -> not (n = m)) metasenv
+ in
+ subst, metasenv
+
+and unify metasenv subst context t1 t2 =
let rec aux test_eq_only metasenv subst context t1 t2 =
let fo_unif test_eq_only metasenv subst t1 t2 =
if t1 === t2 then
aux test_eq_only metasenv subst context term1 term2
with NCicUtils.Subst_not_found _-> raise (UnificationFailure msg))
- | C.Meta (n1,l1), _
- | _, C.Meta (n2,l2) ->
+ | C.Meta (n,lc), t ->
+ try
+ let _,_,term,_ = NCicUtils.lookup_subst n subst in
+ let term = NCicSubstitution.subst_meta lc term in
+ aux test_eq_only metasenv subst context term t
+ with NCicUtils.Subst_not_found _->
+ instantiate test_eq_only metasenv subst context n lc t false
+ | t, C.Meta (n,lc) ->
+ try
+ let _,_,term,_ = NCicUtils.lookup_subst n subst in
+ let term = NCicSubstitution.subst_meta lc term in
+ aux test_eq_only metasenv subst context t term
+ with NCicUtils.Subst_not_found _->
+ instantiate test_eq_only metasenv subst context n lc t true
+ | NCic.Appl (NCic.Meta (i,l)::args), _ when List.mem_assoc i subst ->
+ let _,_,term,_ = NCicUtils.lookup_subst i subst in
+ let term = NCicSubstitution.subst_meta l term in
+ aux test_eq_only metasenv subst context (mk_appl term args) t2
+ | _, NCic.Appl (NCic.Meta (i,l)::args) when List.mem_assoc i subst ->
+ let _,_,term,_ = NCicUtils.lookup_subst i subst in
+ let term = NCicSubstitution.subst_meta l term in
+ aux test_eq_only metasenv subst context t1 (mk_appl term args)
- (try
- let _,_,term,_ = NCicUtils.lookup_subst n1 subst in
- let term = NCicSubstitution.subst_meta l1 term in
- aux test_eq_only metasenv subst context term t2
- with NCicUtils.Subst_not_found _ ->
-
- )
- (try
- let _,_,term,_ = NCicUtils.lookup_subst n2 subst in
- let term = NCicSubstitution.subst_meta l2 term in
- aux test_eq_only metasenv subst context t1 term
- with NCicUtils.Subst_not_found _ -> false)
-
+ | NCic.Appl (NCic.Meta (i,_)::_ as l1),
+ NCic.Appl (NCic.Meta (j,_)::_ as l2) when i=j ->
+ try
+ List.fold_left2
+ (fun (metasenv, subst) t1 t2 ->
+ aux test_eq_only metasenv subst context t1 t2)
+ (metasenv,subst) l1 l2
+ with Invalid_argument _ ->
+ raise (fail_exc metasenv subst context t1 t2)
+
+ | NCic.Appl (NCic.Meta (i,l)::args), _ when not (flexible args) ->
+ (* we verify that none of the args is a Meta,
+ since beta expanding w.r.t a metavariable makes no sense *)
+ let subst, metasenv, beta_expanded =
+ beta_expand_many (* passare swap *)
+ test_equality_only metasenv subst context t2 args ugraph
+ in
+ aux test_eq_only metasenv subst context
+ (C.Meta (i,l)) beta_expanded
+ | _, NCic.Appl (NCic.Meta (i,l)::args) when not(flexible args) ->
+ let subst,metasenv,beta_expanded =
+ beta_expand_many
+ test_equality_only
+ metasenv subst context t1 args ugraph
+ in
+ fo_unif_subst test_equality_only subst context metasenv
+ (C.Meta (i,l)) beta_expanded ugraph1
+ | _,_ ->
+.......
| (C.Appl ((C.Const r1) as _hd1::tl1), C.Appl (C.Const r2::tl2))
when (Ref.eq r1 r2 &&
List.length (E.get_relevance r1) >= List.length tl1) ->
projects / helm.git / blobdiff