Improved memory management for world gen

1 files changed, 30 insertions, 16 deletions

diff --git a/src/kompsos.ads b/src/kompsos.ads
index d2b6fe5..f3f8470 100644
--- a/src/kompsos.ads
+++ b/src/kompsos.ads
@@ -233,6 +233,26 @@ private
 
     type World_Access is access Mu_World'Class;
 
+    type World_Holder is new Ada.Finalization.Controlled with record
+        Ptr : World_Access;
+    end record;
+
+    overriding procedure Initialize
+           (This : in out World_Holder);
+
+    overriding procedure Adjust
+           (This : in out World_Holder);
+
+    overriding procedure Finalize
+           (This : in out World_Holder);
+
+    function Hold
+           (This : in Mu_World'Class)
+        return World_Holder;
+
+    procedure Swap
+           (Left, Right : in out World_Holder);
+
     type Generator_Kind is
        (No_Gen,
         Fresh_Gen,
@@ -246,20 +266,20 @@ private
         when No_Gen =>
             null;
         when Fresh_Gen =>
-            Frs_World  : World_Access;
+            Frs_World  : World_Holder;
             Frs_Name   : SU.Unbounded_String;
         when Unify_Gen =>
-            Uni_World  : World_Access;
+            Uni_World  : World_Holder;
             Uni_Term1  : Term;
             Uni_Term2  : Term;
         when Buffer_Gen =>
-            Buff_World : World_Access;
+            Buff_World : World_Holder;
         when Disjunct_Gen =>
-            Dis_World1 : World_Access;
-            Dis_World2 : World_Access;
+            Dis_World1 : World_Holder;
+            Dis_World2 : World_Holder;
         when Recurse_Gen =>
-            Rec_World : World_Access;
-            Rec_Index : Positive;
+            Rec_World  : World_Holder;
+            Rec_Index  : Positive;
         end case;
     end record;
 
@@ -267,18 +287,12 @@ private
        (Index_Type   => Positive,
         Element_Type => State);
 
-    type Mu_World is new Ada.Finalization.Controlled with record
+    type Mu_World is tagged record
         Possibles  : State_Vectors.Vector;
         Next_Ident : ID_Number;
         Engine     : Generator;
     end record;
 
-    overriding procedure Adjust
-           (This : in out Mu_World);
-
-    overriding procedure Finalize
-           (This : in out Mu_World);
-
     function Has_State
            (This  : in out Mu_World;
             Index : in     Positive)
@@ -293,8 +307,8 @@ private
 
     use type State_Vectors.Vector;
 
-    Empty_Mu_World : constant Mu_World := (Ada.Finalization.Controlled with
-        Possibles  => State_Vectors.Empty_Vector & Empty_State,
+    Empty_Mu_World : constant Mu_World :=
+       (Possibles  => State_Vectors.Empty_Vector & Empty_State,
         Next_Ident => 0,
         Engine     => (Kind => No_Gen));