X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_refiner%2FnCicUnification.ml;h=bfa1388a98b965d0489b34aebbff4721b0e714df;hb=c22f39a5d5afc0ef55beb221e00e2e6703b13d90;hp=a0cda6861c512ef8e31e0974a14af5d7768457ad;hpb=dc1902ae1e458e5120af63d880dbd08255bef238;p=helm.git

diff --git a/helm/software/components/ng_refiner/nCicUnification.ml b/helm/software/components/ng_refiner/nCicUnification.ml
index a0cda6861..bfa1388a9 100644
--- a/helm/software/components/ng_refiner/nCicUnification.ml
+++ b/helm/software/components/ng_refiner/nCicUnification.ml
@@ -36,36 +36,45 @@ let mk_appl ~upto hd 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 =
+let eta_reduce subst t = 
+  let delift_if_not_occur body =
     try 
-        NCicSubstitution.psubst ~avoid_beta_redexes:true
-          (fun () -> raise WrongShape) [()] body
-    with WrongShape -> orig
+        Some (NCicSubstitution.psubst ~avoid_beta_redexes:true
+          (fun () -> raise WrongShape) [()] body)
+    with WrongShape -> None
+  in 
+  let rec eat_lambdas ctx = function
+    | NCic.Lambda (name, src, tgt) -> 
+        eat_lambdas ((name, src) :: ctx) tgt
+    | NCic.Meta (i,lc) as t->
+        (try 
+          let _,_,t,_ = NCicUtils.lookup_subst i subst in
+          let t = NCicSubstitution.subst_meta lc t in
+          eat_lambdas ctx t
+        with Not_found -> ctx, t)
+    | t -> ctx, t
   in
-  function
-  | NCic.Lambda(_, _, NCic.Appl [hd; NCic.Rel 1]) as orig ->
-      delift_if_not_occur hd orig
-  | NCic.Lambda(_, _, 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 context_body = eat_lambdas [] t in
+  let rec aux = function
+    | [],body -> body
+    | (name, src)::ctx, (NCic.Appl (hd::[NCic.Rel 1]) as bo) -> 
+        (match delift_if_not_occur hd with
+        | None -> aux (ctx,NCic.Lambda(name,src, bo)) 
+        | Some bo -> aux (ctx,bo))
+    | (name, src)::ctx, (NCic.Appl args as bo) 
+      when HExtlib.list_last args = NCic.Rel 1 -> 
+        let args, _ = HExtlib.split_nth (List.length args - 1) args in
+        (match delift_if_not_occur (NCic.Appl args) with
+        | None -> aux (ctx,NCic.Lambda(name,src, bo)) 
+        | Some bo -> aux (ctx,bo))
+    | (name, src) :: ctx, t ->
+        aux (ctx,NCic.Lambda(name,src, t)) 
+  in
+    aux context_body
 ;;
- 
+
 module C = NCic;;
 module Ref = NReference;;
 
@@ -98,74 +107,40 @@ let fix_sorts swap metasenv subst context meta t =
     aux () t
 ;;
 
-let rec beta_expand hdb 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' =
+let is_locked n subst =
    try
-    let metasenv, subst =
-     if swap then
-      unify hdb test_eq_only metasenv subst context t' (NCicSubstitution.lift n arg)
-     else
-      unify hdb test_eq_only metasenv subst context (NCicSubstitution.lift n arg) t'
-    in
-     (metasenv, subst), NCic.Rel (1 + n)
-   with Uncertain _ | UnificationFailure _ ->
-       match t' with
-       | NCic.Rel m as 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 ms, tgt1 = aux k (metasenv, subst) tgt in 
-           if src == src1 && tgt == tgt1 then ms, orig else
-           ms, NCic.Prod (name, src1, tgt1)
-       | t -> 
-           NCicUntrusted.map_term_fold_a 
-             (fun e (n,ctx,teq) -> n+1,e::ctx,teq) 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 (NCic.Lambda (fresh_name,argty,t1)) in
-  try 
-    ignore(NCicTypeChecker.typeof ~metasenv ~subst context t2);
-    metasenv, subst, t2
-  with NCicTypeChecker.TypeCheckerFailure _ -> 
-    metasenv, subst, NCic.Lambda ("_", argty, NCicSubstitution.lift 1 arg)
+     match NCicUtils.lookup_subst n subst with
+     | Some tag, _,_,_ when NCicMetaSubst.is_out_scope_tag tag -> true
+     | _ -> false
+   with NCicUtils.Subst_not_found _ -> false
+;;
 
-and beta_expand_many hdb test_equality_only swap metasenv subst context t args =
-(* (*D*)  inside 'B'; try let rc = *)
-  pp (lazy (String.concat ", "
-     (List.map (NCicPp.ppterm ~metasenv ~subst ~context)
-     args) ^ " ∈ " ^ NCicPp.ppterm ~metasenv ~subst ~context t));
-  let _, subst, metasenv, hd =
-    List.fold_right
-      (fun arg (num,subst,metasenv,t) ->
-         let metasenv, subst, t =
-           beta_expand hdb num test_equality_only swap metasenv subst context t arg
-         in
-           num+1,subst,metasenv,t)
-      args (1,subst,metasenv,t) 
-  in
-  pp (lazy ("Head syntesized by b-exp: " ^ 
-    NCicPp.ppterm ~metasenv ~subst ~context hd));
-    metasenv, subst, hd
-(* (*D*)  in outside (); rc with exn -> outside (); raise exn *)
 
-and instantiate hdb test_eq_only metasenv subst context n lc t swap =
+let rec lambda_intros metasenv subst context t args =
+ let tty = NCicTypeChecker.typeof ~metasenv ~subst context t in
+ let argsty = List.map (NCicTypeChecker.typeof ~metasenv ~subst context) args in
+ let rec mk_lambda context n = function
+   | [] -> 
+       let metasenv, _, bo, _ = 
+         NCicMetaSubst.mk_meta metasenv context 
+           (`WithType (NCicSubstitution.lift n tty))
+       in
+       metasenv, bo
+   | ty::tail -> 
+       let name = "HBeta"^string_of_int n in
+       let ty = NCicSubstitution.lift n ty in
+       let metasenv, bo = mk_lambda ((name,NCic.Decl ty)::context) (n+1) tail in
+       metasenv, NCic.Lambda (name, ty, bo)
+ in
+   mk_lambda context 0 argsty
+
+and instantiate rdb test_eq_only metasenv subst context n lc t swap =
  (*D*)  inside 'I'; try let rc =  
          pp (lazy(string_of_int n ^ " :=?= "^
            NCicPp.ppterm ~metasenv ~subst ~context t));
   let unify test_eq_only m s c t1 t2 = 
-    if swap then unify hdb test_eq_only m s c t2 t1 
-    else unify hdb test_eq_only m s c t1 t2
+    if swap then unify rdb test_eq_only m s c t2 t1 
+    else unify rdb test_eq_only m s c t1 t2
   in
   let name, ctx, ty = NCicUtils.lookup_meta n metasenv in
   let metasenv, subst, t = 
@@ -204,17 +179,32 @@ and instantiate hdb test_eq_only metasenv subst context n lc t swap =
               pp msg; assert false
        in
        let lty = NCicSubstitution.subst_meta lc ty in
-       pp (lazy ("On the types: " ^
-        NCicPp.ppterm ~metasenv ~subst ~context:ctx ty ^ " ~~~ " ^
-        NCicPp.ppterm ~metasenv ~subst ~context lty ^ " === "
-         ^ NCicPp.ppterm ~metasenv ~subst ~context ty_t)); 
-       let metasenv,subst= unify test_eq_only metasenv subst context lty ty_t in
-       metasenv, subst, t
+       match ty_t with
+       | NCic.Implicit _ -> 
+           raise (UnificationFailure 
+             (lazy "trying to unify a term with a type"))
+       | ty_t -> 
+          pp (lazy ("On the types: " ^
+           NCicPp.ppterm ~metasenv ~subst ~context:ctx ty ^ " ~~~ " ^
+           NCicPp.ppterm ~metasenv ~subst ~context lty ^ " === "
+            ^ NCicPp.ppterm ~metasenv ~subst ~context ty_t)); 
+          let metasenv,subst = 
+            unify test_eq_only metasenv subst context lty ty_t in
+          metasenv, subst, t
   in
          pp (lazy(string_of_int n ^ " := 111 = "^
            NCicPp.ppterm ~metasenv ~subst ~context t));
   let (metasenv, subst), t = 
-    try NCicMetaSubst.delift metasenv subst context n lc t
+    try 
+      NCicMetaSubst.delift 
+       ~unify:(fun m s c t1 t2 -> 
+         let ind = !indent in
+         let res = 
+           try Some (unify test_eq_only m s c t1 t2 )
+           with UnificationFailure _ | Uncertain _ -> None
+         in
+         indent := ind; res) 
+       metasenv subst context n lc t
     with NCicMetaSubst.Uncertain msg -> 
          pp (lazy ("delift fails: " ^ Lazy.force msg));
          raise (Uncertain msg)
@@ -244,7 +234,7 @@ and instantiate hdb test_eq_only metasenv subst context n lc t swap =
     metasenv, subst
  (*D*)  in outside(); rc with exn -> outside (); raise exn 
 
-and unify hdb test_eq_only metasenv subst context t1 t2 =
+and unify rdb test_eq_only metasenv subst context t1 t2 =
  (*D*) inside 'U'; try let rc =
    let fo_unif test_eq_only metasenv subst t1 t2 =
     (*D*) inside 'F'; try let rc =  
@@ -271,13 +261,13 @@ and unify hdb test_eq_only metasenv subst context t1 t2 =
 
        | (C.Lambda (name1,s1,t1), C.Lambda(_,s2,t2)) 
        | (C.Prod (name1,s1,t1), C.Prod(_,s2,t2)) ->
-           let metasenv, subst = unify hdb true metasenv subst context s1 s2 in
-           unify hdb test_eq_only metasenv subst ((name1, C.Decl s1)::context) t1 t2
+           let metasenv, subst = unify rdb true metasenv subst context s1 s2 in
+           unify rdb test_eq_only metasenv subst ((name1, C.Decl s1)::context) t1 t2
        | (C.LetIn (name1,ty1,s1,t1), C.LetIn(_,ty2,s2,t2)) ->
-           let metasenv,subst=unify hdb test_eq_only metasenv subst context ty1 ty2 in
-           let metasenv,subst=unify hdb test_eq_only metasenv subst context s1 s2 in
+           let metasenv,subst=unify rdb test_eq_only metasenv subst context ty1 ty2 in
+           let metasenv,subst=unify rdb test_eq_only metasenv subst context s1 s2 in
            let context = (name1, C.Def (s1,ty1))::context in
-           unify hdb test_eq_only metasenv subst context t1 t2
+           unify rdb test_eq_only metasenv subst context t1 t2
 
        | (C.Meta (n1,(s1,l1 as lc1)),C.Meta (n2,(s2,l2 as lc2))) when n1 = n2 ->
           (try 
@@ -288,7 +278,7 @@ and unify hdb test_eq_only metasenv subst context t1 t2 =
              (fun t1 t2 (metasenv, subst, to_restrict, i) -> 
                 try 
                   let metasenv, subst = 
-                   unify hdb test_eq_only metasenv subst context 
+                   unify rdb test_eq_only metasenv subst context 
                     (NCicSubstitution.lift s1 t1) (NCicSubstitution.lift s2 t2)
                   in
                   metasenv, subst, to_restrict, i-1  
@@ -309,37 +299,66 @@ and unify hdb test_eq_only metasenv subst context t1 t2 =
                 let _,_,term,_ = NCicUtils.lookup_subst n1 subst in
                 let term1 = NCicSubstitution.subst_meta lc1 term in
                 let term2 = NCicSubstitution.subst_meta lc2 term in
-                  unify hdb test_eq_only metasenv subst context term1 term2
+                  unify rdb test_eq_only metasenv subst context term1 term2
               with NCicUtils.Subst_not_found _-> raise (UnificationFailure msg))
+       
+       | _, NCic.Meta (n, _) when is_locked n subst ->
+           (let (metasenv, subst), i = 
+              match NCicReduction.whd ~subst context t1 with
+              | NCic.Appl (NCic.Meta (i,l)::args) when
+                  not (NCicMetaSubst.flexible subst args) 
+                ->
+                 let metasenv, lambda_Mj =
+                   lambda_intros metasenv subst context t1 args
+                 in
+                   unify rdb test_eq_only metasenv subst context 
+                    (C.Meta (i,l)) lambda_Mj,
+                   i
+              | NCic.Meta (i,_) -> (metasenv, subst), i
+              | _ -> assert false
+             in
+              let t1 = NCicReduction.whd ~subst context t1 in
+              let j, lj = 
+                match t1 with NCic.Meta (j,l) -> j, l | _ -> assert false
+              in
+              let metasenv, subst = 
+                instantiate rdb test_eq_only metasenv subst context j lj t2 true
+              in
+              (try
+                let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
+                let term = eta_reduce subst term in
+                let subst = List.filter (fun (j,_) -> j <> i) subst in
+                metasenv, ((i, (name, ctx, term, ty)) :: subst)
+              with Not_found -> assert false))
 
        | C.Meta (n,lc), t -> 
            (try 
              let _,_,term,_ = NCicUtils.lookup_subst n subst in
              let term = NCicSubstitution.subst_meta lc term in
-               unify hdb test_eq_only metasenv subst context term t
+               unify rdb test_eq_only metasenv subst context term t
            with NCicUtils.Subst_not_found _-> 
-             instantiate hdb test_eq_only metasenv subst context n lc 
+             instantiate rdb test_eq_only metasenv subst context n lc 
                (NCicReduction.head_beta_reduce ~subst t) false)
 
        | t, C.Meta (n,lc) -> 
            (try 
              let _,_,term,_ = NCicUtils.lookup_subst n subst in
              let term = NCicSubstitution.subst_meta lc term in
-               unify hdb test_eq_only metasenv subst context t term
+               unify rdb test_eq_only metasenv subst context t term
            with NCicUtils.Subst_not_found _-> 
-             instantiate hdb test_eq_only metasenv subst context n lc 
+             instantiate rdb test_eq_only metasenv subst context n lc 
               (NCicReduction.head_beta_reduce ~subst 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
-              unify hdb test_eq_only metasenv subst context 
+              unify rdb test_eq_only metasenv subst context 
                 (mk_appl ~upto:(List.length args) 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
-              unify hdb test_eq_only metasenv subst context t1 
+              unify rdb test_eq_only metasenv subst context t1 
                 (mk_appl ~upto:(List.length args) term args)
 
        |  NCic.Appl (NCic.Meta (i,_)::_ as l1),
@@ -347,30 +366,50 @@ and unify hdb test_eq_only metasenv subst context t1 t2 =
             (try
               List.fold_left2 
                 (fun (metasenv, subst) t1 t2 ->
-                  unify hdb test_eq_only metasenv subst context t1 t2)
+                  unify rdb 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) ->
+       | NCic.Appl (NCic.Meta (i,l)::args), _ when 
+         not (NCicMetaSubst.flexible subst args) ->
            (* we verify that none of the args is a Meta, 
               since beta expanding w.r.t a metavariable makes no sense  *)
-              let metasenv, subst, beta_expanded =
-                beta_expand_many hdb 
-                  test_eq_only false 
-                  metasenv subst context t2 args
+              let metasenv, lambda_Mj =
+                lambda_intros metasenv subst context t1 args
               in
-                unify hdb test_eq_only metasenv subst context 
-                  (C.Meta (i,l)) beta_expanded 
-
-       | _, NCic.Appl (NCic.Meta (i,l)::args) when not(flexible args) ->
-              let metasenv, subst, beta_expanded =
-                beta_expand_many hdb 
-                  test_eq_only true 
-                  metasenv subst context t1 args
+              let metasenv, subst = 
+                unify rdb test_eq_only metasenv subst context 
+                  (C.Meta (i,l)) lambda_Mj
               in
-                unify hdb test_eq_only metasenv subst context 
-                  beta_expanded (C.Meta (i,l))
+              let metasenv, subst = 
+                unify rdb test_eq_only metasenv subst context t1 t2 
+              in
+              (try
+                let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
+                let term = eta_reduce subst term in
+                let subst = List.filter (fun (j,_) -> j <> i) subst in
+                metasenv, ((i, (name, ctx, term, ty)) :: subst)
+              with Not_found -> assert false)
+
+       | _, NCic.Appl (NCic.Meta (i,l)::args) when 
+         not(NCicMetaSubst.flexible subst args) ->
+              let metasenv, lambda_Mj =
+                lambda_intros metasenv subst context t2 args
+              in
+              let metasenv, subst =
+                unify rdb test_eq_only metasenv subst context 
+                 lambda_Mj (C.Meta (i,l))
+              in
+              let metasenv, subst = 
+                unify rdb test_eq_only metasenv subst context t1 t2 
+              in
+              (try
+                let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
+                let term = eta_reduce subst term in
+                let subst = List.filter (fun (j,_) -> j <> i) subst in
+                metasenv, ((i, (name, ctx, term, ty)) :: subst)
+              with Not_found -> assert false)
 
        (* processing this case here we avoid a useless small delta step *)
        | (C.Appl ((C.Const r1) as _hd1::tl1), C.Appl (C.Const r2::tl2)) 
@@ -378,7 +417,10 @@ and unify hdb test_eq_only metasenv subst context t1 t2 =
            let relevance = NCicEnvironment.get_relevance r1 in
            let relevance = match r1 with
              | Ref.Ref (_,Ref.Con (_,_,lno)) ->
-                 let _,relevance = HExtlib.split_nth lno relevance in
+                 let relevance =
+                  try snd (HExtlib.split_nth lno relevance)
+                  with Failure _ -> []
+                 in
                    HExtlib.mk_list false lno @ relevance
              | _ -> relevance
            in
@@ -389,7 +431,7 @@ and unify hdb test_eq_only metasenv subst context t1 t2 =
                     let b, relevance = 
                       match relevance with b::tl -> b,tl | _ -> true, [] in
                     let metasenv, subst = 
-                      try unify hdb test_eq_only metasenv subst context t1 t2
+                      try unify rdb test_eq_only metasenv subst context t1 t2
                       with UnificationFailure _ | Uncertain _ when not b ->
                         metasenv, subst
                     in
@@ -421,16 +463,16 @@ and unify hdb test_eq_only metasenv subst context t1 t2 =
              raise (uncert_exc metasenv subst context t1 t2) 
            else
              let metasenv, subst = 
-              unify hdb test_eq_only metasenv subst context outtype1 outtype2 in
+              unify rdb test_eq_only metasenv subst context outtype1 outtype2 in
              let metasenv, subst = 
-               try unify hdb test_eq_only metasenv subst context term1 term2 
+               try unify rdb test_eq_only metasenv subst context term1 term2 
                with UnificationFailure _ | Uncertain _ when is_prop -> 
                  metasenv, subst
              in
              (try
               List.fold_left2 
                (fun (metasenv,subst) -> 
-                  unify hdb test_eq_only metasenv subst context)
+                  unify rdb test_eq_only metasenv subst context)
                (metasenv, subst) pl1 pl2
              with Invalid_argument _ -> 
                raise (uncert_exc metasenv subst context t1 t2))
@@ -443,22 +485,26 @@ and unify hdb test_eq_only metasenv subst context t1 t2 =
     in
     let try_hints metasenv subst t1 t2 (* exc*) =
 (*
-            prerr_endline ("\n\n\n looking for hints for : " ^ 
-              NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " ==?== " ^
-              NCicPp.ppterm ~metasenv ~subst ~context t2);
+      prerr_endline ("\nProblema:\n" ^
+        NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " =?= " ^
+        NCicPp.ppterm ~metasenv ~subst ~context t2);
 *)
       let candidates = 
-        NCicUnifHint.look_for_hint hdb metasenv subst context t1 t2
+        NCicUnifHint.look_for_hint rdb metasenv subst context t1 t2
       in
       let rec cand_iter = function
         | [] -> None (* raise exc *)
         | (metasenv,(c1,c2),premises)::tl -> 
 (*
-            prerr_endline ("\n attempt: " ^ 
-              NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " ==?== " ^
-              NCicPp.ppterm ~metasenv ~subst ~context c1 ^  " AND " ^
-              NCicPp.ppterm ~metasenv ~subst ~context c2 ^  " ==?== " ^
-              NCicPp.ppterm ~metasenv ~subst ~context t2);
+            prerr_endline ("\nProvo il candidato:\n" ^ 
+              String.concat "\n"
+                (List.map 
+                  (fun (a,b) ->
+                   NCicPp.ppterm ~metasenv ~subst ~context a ^  " =?= " ^
+                   NCicPp.ppterm ~metasenv ~subst ~context b) premises) ^
+              "\n-------------------------------------------\n"^
+              NCicPp.ppterm ~metasenv ~subst ~context c1 ^  " = " ^
+              NCicPp.ppterm ~metasenv ~subst ~context c2);
 *)
             try 
               let metasenv,subst = 
@@ -468,13 +514,12 @@ and unify hdb test_eq_only metasenv subst context t1 t2 =
               let metasenv,subst = 
                 List.fold_left 
                   (fun (metasenv, subst) (x,y) ->
-                     unify hdb test_eq_only metasenv subst context x y)
+                     unify rdb test_eq_only metasenv subst context x y)
                   (metasenv, subst) premises
               in
               Some (metasenv, subst)
             with
               UnificationFailure _ | Uncertain _ ->
-                prerr_endline (" <candidate fails");
                 cand_iter tl
       in
         cand_iter candidates
@@ -570,8 +615,6 @@ pp (lazy (string_of_bool norm1 ^ " ?? " ^ string_of_bool norm2));
  (*D*)  in outside(); rc with exn -> outside (); raise exn 
 ;;
 
-let unify hdb = 
+let unify rdb ?(test_eq_only=false) = 
   indent := "";      
-  unify hdb false;;
-
-
+  unify rdb test_eq_only;;