diff --git a/src/stdpath.ml b/src/stdpath.ml
index f3cd19db9..c85a32af0 100644
--- a/src/stdpath.ml
+++ b/src/stdpath.ml
@@ -1 +1 @@
-let path = "/home/db/.opam/ocaml-system.4.07.1/share/Lama"
+let path = "/home/db/.opam/4.07.1+fp/share/Lama"
diff --git a/src/version.ml b/src/version.ml
index 8e8bdb689..434ba2507 100644
--- a/src/version.ml
+++ b/src/version.ml
@@ -1 +1 @@
-let version = "Version 1.00, 674214cea, Sat Oct 31 02:17:44 2020 +0300"
+let version = "Version 1.00, 695ddc7d8, Sat Oct 31 02:59:20 2020 +0300"
diff --git a/stdlib/Collection.lama b/stdlib/Collection.lama
index 2ec6e5610..ed09875aa 100644
--- a/stdlib/Collection.lama
+++ b/stdlib/Collection.lama
@@ -295,26 +295,36 @@ public fun foldSet (f, acc, s) {
 }
 
 -- Hash consing
-public fun emptyMemo () {
-  ref (emptyMap (compare))
+public fun emptyCustomMemo (pred, compare) {
+  [pred, emptyMap (compare)]
 }
 
-public fun lookupMemo (m, v) {
+public fun emptyMemo () {
+--  ref (emptyMap (compare))
+  emptyCustomMemo ({}, compare)
+}
+
+public fun lookupMemo (mm@[p, m], v) {
+  case p of
+    #fun -> if p (v) then return v fi
+  | _    -> skip
+  esac;
+  
   case v of
     #unboxed -> v
   | _ ->
-     case findMap (deref (m), v) of
+     case findMap (m, v) of
        Some (w) -> w
      | None ->
         case v of
-          #string -> m ::= addMap (deref (m), v, v); v        
+          #string -> mm[1] := addMap (m, v, v); v        
         | _ ->
           local vc = clone (v), i = case vc of #fun -> 1 | _ -> 0 esac;          
           for skip, i < v.length, i := i + 1 do
-            local vci = lookupMemo (m, vc [i]);
+            local vci = lookupMemo (mm, vc [i]);
             vc [i] := vci
           od;
-          m ::= addMap (deref (m), vc, vc);
+          mm [1] := addMap (m, vc, vc);
           vc
         esac
      esac
diff --git a/stdlib/Ostap.lama b/stdlib/Ostap.lama
index 2e7d2bcf9..ee22d8637 100644
--- a/stdlib/Ostap.lama
+++ b/stdlib/Ostap.lama
@@ -18,7 +18,7 @@ public fun logOn () {
 
 public fun initOstap () {
   tab    := ref (emptyHashTab (1024, hash, compare));
-  restab := emptyMemo ();
+  restab := emptyCustomMemo (fun (x) {case x of #string -> true | _ -> false esac}, compare);
   hct    := emptyMemo ()
 }