Counter for next available Variable now held by each Goal instead of being global

1 files changed, 80 insertions, 79 deletions

diff --git a/src/kompsos.adb b/src/kompsos.adb
index 080683b..4a34b1b 100644
--- a/src/kompsos.adb
+++ b/src/kompsos.adb
@@ -55,20 +55,20 @@ package body Kompsos is
 
 
 
-    --  Goals  --
+    --  Goal Graphs  --
 
-    procedure Free is new Ada.Unchecked_Deallocation (Goal_Component, Goal_Component_Access);
+    procedure Free is new Ada.Unchecked_Deallocation (Graph_Component, Graph_Component_Access);
 
 
     procedure Initialize
-           (This : in out Goal) is
+           (This : in out Goal_Graph) is
     begin
         This.Actual := null;
     end Initialize;
 
 
     procedure Adjust
-           (This : in out Goal) is
+           (This : in out Goal_Graph) is
     begin
         if This.Actual /= null then
             This.Actual.Counter := This.Actual.Counter + 1;
@@ -77,7 +77,7 @@ package body Kompsos is
 
 
     procedure Finalize
-           (This : in out Goal) is
+           (This : in out Goal_Graph) is
     begin
         if This.Actual /= null then
             This.Actual.Counter := This.Actual.Counter - 1;
@@ -209,43 +209,24 @@ package body Kompsos is
 
 
 
-    --  Goals  --
+    --  Goal Graphs  --
 
-    package Goal_Convert is new System.Address_To_Access_Conversions (Goal_Component);
+    package Graph_Convert is new System.Address_To_Access_Conversions (Graph_Component);
 
     function "<"
-           (Left, Right : in Goal_Component_Access)
+           (Left, Right : in Graph_Component_Access)
         return Boolean
     is
         use System.Storage_Elements;
     begin
         return
-            To_Integer (Goal_Convert.To_Address (Goal_Convert.Object_Pointer (Left))) <
-            To_Integer (Goal_Convert.To_Address (Goal_Convert.Object_Pointer (Right)));
+            To_Integer (Graph_Convert.To_Address (Graph_Convert.Object_Pointer (Left))) <
+            To_Integer (Graph_Convert.To_Address (Graph_Convert.Object_Pointer (Right)));
     end "<";
 
 
 
 
-    ------------------------
-    --  Internal Helpers  --
-    ------------------------
-
-    --  Variables  --
-
-    Next_Variable : Variable := Variable'First;
-
-    function Next_Gen
-        return Variable is
-    begin
-        return Result : constant Variable := Next_Variable do
-            Next_Variable := Next_Variable + 1;
-        end return;
-    end Next_Gen;
-
-
-
-
     -------------------
     --  microKanren  --
     -------------------
@@ -256,7 +237,9 @@ package body Kompsos is
            (This : in out Goal'Class)
         return Term is
     begin
-        return Term (T (Next_Gen));
+        return Result : constant Term := Term (T (This.Next_Var)) do
+            This.Next_Var := This.Next_Var + 1;
+        end return;
     end Fresh;
 
 
@@ -307,13 +290,15 @@ package body Kompsos is
             Left, Right : in Term'Class)
         return Goal is
     begin
-        return Result : constant Goal := (Ada.Finalization.Controlled with
-            Actual => new Goal_Component'(
-               (Kind      => Unify_Node,
-                Counter   => 1,
-                Uni_Goal  => This,
-                Uni_Term1 => Term (Left),
-                Uni_Term2 => Term (Right))));
+        return Result : constant Goal :=
+           (Graph    => (Ada.Finalization.Controlled with
+                Actual => new Graph_Component'(
+                   (Kind      => Unify_Node,
+                    Counter   => 1,
+                    Uni_Goal  => This.Graph,
+                    Uni_Term1 => Term (Left),
+                    Uni_Term2 => Term (Right)))),
+            Next_Var => This.Next_Var);
     end Unify;
 
 
@@ -332,12 +317,14 @@ package body Kompsos is
            (Left, Right : in Goal)
         return Goal is
     begin
-        return Result : constant Goal := (Ada.Finalization.Controlled with
-            Actual => new Goal_Component'(
-               (Kind      => Disjunct_Node,
-                Counter   => 1,
-                Dis_Goal1 => Left,
-                Dis_Goal2 => Right)));
+        return Result : constant Goal :=
+           (Graph    => (Ada.Finalization.Controlled with
+                Actual => new Graph_Component'(
+                   (Kind      => Disjunct_Node,
+                    Counter   => 1,
+                    Dis_Goal1 => Left.Graph,
+                    Dis_Goal2 => Right.Graph))),
+            Next_Var => Variable'Max (Left.Next_Var, Right.Next_Var));
     end Disjunct;
 
 
@@ -354,16 +341,22 @@ package body Kompsos is
         return Goal is
     begin
         if Inputs'Length = 0 then
-            return (Ada.Finalization.Controlled with Actual => null);
+            return Empty_Goal;
         elsif Inputs'Length = 1 then
             return Inputs (Inputs'First);
         else
-            return Result : constant Goal := (Ada.Finalization.Controlled with
-                Actual => new Goal_Component'(
-                   (Kind      => Disjunct_Node,
-                    Counter   => 1,
-                    Dis_Goal1 => Inputs (Inputs'First),
-                    Dis_Goal2 => Disjunct (Inputs (Inputs'First + 1 .. Inputs'Last)))));
+            declare
+                Rest : constant Goal := Disjunct (Inputs (Inputs'First + 1 .. Inputs'Last));
+            begin
+                return Result : constant Goal :=
+                   (Graph    => (Ada.Finalization.Controlled with
+                        Actual => new Graph_Component'(
+                           (Kind      => Disjunct_Node,
+                            Counter   => 1,
+                            Dis_Goal1 => Inputs (Inputs'First).Graph,
+                            Dis_Goal2 => Rest.Graph))),
+                    Next_Var => Variable'Max (Inputs (Inputs'First).Next_Var, Rest.Next_Var));
+            end;
         end if;
     end Disjunct;
 
@@ -384,12 +377,14 @@ package body Kompsos is
             Func : in Junction_Zero_Func)
         return Goal is
     begin
-        return Result : constant Goal := (Ada.Finalization.Controlled with
-            Actual => new Goal_Component'(
-               (Kind     => Conjunct_Node,
-                Counter  => 1,
-                Con_Goal => This,
-                Con_Data => Lazy_Holders.To_Holder ((Kind => Zero_Arg, ZFunc => Func)))));
+        return Result : constant Goal :=
+           (Graph    => (Ada.Finalization.Controlled with
+                Actual => new Graph_Component'(
+                   (Kind     => Conjunct_Node,
+                    Counter  => 1,
+                    Con_Goal => This.Graph,
+                    Con_Data => Lazy_Holders.To_Holder ((Kind => Zero_Arg, ZFunc => Func))))),
+            Next_Var => This.Next_Var);
     end Conjunct;
 
 
@@ -407,15 +402,17 @@ package body Kompsos is
             Input : in Term'Class)
         return Goal is
     begin
-        return Result : constant Goal := (Ada.Finalization.Controlled with
-            Actual => new Goal_Component'(
-               (Kind     => Conjunct_Node,
-                Counter  => 1,
-                Con_Goal => This,
-                Con_Data => Lazy_Holders.To_Holder
-                   ((Kind   => One_Arg,
-                     OFunc  => Func,
-                     OInput => Term (Input))))));
+        return Result : constant Goal :=
+           (Graph    => (Ada.Finalization.Controlled with
+                Actual => new Graph_Component'(
+                   (Kind     => Conjunct_Node,
+                    Counter  => 1,
+                    Con_Goal => This.Graph,
+                    Con_Data => Lazy_Holders.To_Holder
+                       ((Kind   => One_Arg,
+                         OFunc  => Func,
+                         OInput => Term (Input)))))),
+            Next_Var => This.Next_Var);
     end Conjunct;
 
 
@@ -434,15 +431,17 @@ package body Kompsos is
             Inputs : in Term_Array)
         return Goal is
     begin
-        return Result : constant Goal := (Ada.Finalization.Controlled with
-            Actual => new Goal_Component'(
-               (Kind     => Conjunct_Node,
-                Counter  => 1,
-                Con_Goal => This,
-                Con_Data => Lazy_Holders.To_Holder
-                   ((Kind   => Many_Arg,
-                     MFunc  => Func,
-                     MInput => Term_Array_Holders.To_Holder (Inputs))))));
+        return Result : constant Goal :=
+           (Graph    => (Ada.Finalization.Controlled with
+                Actual => new Graph_Component'(
+                   (Kind     => Conjunct_Node,
+                    Counter  => 1,
+                    Con_Goal => This.Graph,
+                    Con_Data => Lazy_Holders.To_Holder
+                       ((Kind   => Many_Arg,
+                         MFunc  => Func,
+                         MInput => Term_Array_Holders.To_Holder (Inputs)))))),
+            Next_Var => This.Next_Var);
     end Conjunct;
 
 
@@ -467,11 +466,13 @@ package body Kompsos is
            (This : in Goal)
         return Goal is
     begin
-        return Result : constant Goal := (Ada.Finalization.Controlled with
-            Actual => new Goal_Component'(
-               (Kind     => Recurse_Node,
-                Counter  => 1,
-                Rec_Goal => This)));
+        return Result : constant Goal :=
+           (Graph    => (Ada.Finalization.Controlled with
+                Actual => new Graph_Component'(
+                   (Kind     => Recurse_Node,
+                    Counter  => 1,
+                    Rec_Goal => This.Graph))),
+            Next_Var => This.Next_Var);
     end Recurse;