1 files changed, 167 insertions, 13 deletions
diff --git a/src/packrat-graphs.ads b/src/packrat-graphs.ads
index 4095360..877be3a 100644
--- a/src/packrat-graphs.ads
+++ b/src/packrat-graphs.ads
@@ -1,5 +1,10 @@
 
 
+with
+
+    Ada.Iterator_Interfaces;
+
+
 generic
     type Label_Enum is (<>);
     type Element is private;
@@ -8,10 +13,70 @@ generic
 package Packrat.Graphs is
 
 
+    type Node is new My_Interfaces.Node with private;
+
+    type Node_Reference (Data : not null access Node'Class) is limited null record
+        with Implicit_Dereference => Data;
+
 
     type Cursor is new My_Interfaces.Cursor with private;
 
-    type Parse_Graph is new My_Interfaces.Graph with private;
+    type Iter_Cursor (Data : not null access Cursor) is private
+        with Implicit_Dereference => Data;
+
+
+    type Parse_Graph is new My_Interfaces.Graph with private
+        with Default_Iterator  => Iterate,
+             Iterator_Element  => Node_Reference,
+             Variable_Indexing => Node_At;
+
+
+
+
+    No_Position : constant Cursor;
+
+    Empty_Graph : constant Parse_Graph;
+
+
+
+
+    function Leaf
+           (New_Item : in Element_Array;
+            Start    : in Positive;
+            Finish   : in Natural)
+        return Node;
+
+    function Branch
+           (Label  : in Label_Enum;
+            Start  : in Positive;
+            Finish : in Natural)
+        return Node;
+
+
+    function Is_Leaf
+           (This : in Node)
+        return Boolean;
+
+    function Is_Branch
+           (This : in Node)
+        return Boolean;
+
+
+    function Label
+           (This : in Node)
+        return Label_Enum;
+
+    function Elements
+           (This : in Node)
+        return Element_Array;
+
+    function Start
+           (This : in Node)
+        return Positive;
+
+    function Finish
+           (This : in Node)
+        return Natural;
 
 
 
@@ -27,6 +92,10 @@ package Packrat.Graphs is
            (Position : in Cursor)
         return Natural;
 
+    function Is_Node
+           (Position : in Cursor)
+        return Boolean;
+
     function Is_Root
            (Position : in Cursor)
         return Boolean;
@@ -39,6 +108,9 @@ package Packrat.Graphs is
            (Position : in Cursor)
         return Boolean;
 
+
+
+
     function Label
            (Position : in Cursor)
         return Label_Enum;
@@ -47,9 +119,6 @@ package Packrat.Graphs is
            (Position : in Cursor)
         return Element_Array;
 
-
-
-
     function Start
            (Position : in Cursor)
         return Positive;
@@ -145,17 +214,16 @@ package Packrat.Graphs is
 
 
 
-    function Leaf
-           (New_Item : in Element_Array;
-            Start    : in Positive;
-            Finish   : in Natural)
+    function Singleton
+           (Input : in My_Interfaces.Node'Class)
         return Parse_Graph;
 
-    function Branch
-           (Label  : in Label_Enum;
-            Start  : in Positive;
-            Finish : in Natural)
-        return Parse_Graph;
+    function Node_At
+           (Container : in Parse_Graph;
+            Position  : in My_Interfaces.Cursor'Class)
+        return Node_Reference
+    with Pre =>
+            Position.Is_Node;
 
 
 
@@ -221,15 +289,101 @@ package Packrat.Graphs is
 
 
 
+    function Is_Valid_Node
+           (Position : in Iter_Cursor)
+        return Boolean;
+
+
+
+
+    package Graph_Iterators is
+        new Ada.Iterator_Interfaces (Iter_Cursor, Is_Valid_Node);
+
+    type Choosing_Function is access function
+           (Position : in Cursor)
+        return Natural;
+
+
+
+
+    function Iterate
+           (This : in Parse_Graph)
+        return Graph_Iterators.Reversible_Iterator'Class;
+
+    function Iterate_Subtree
+           (This     : in Parse_Graph;
+            Position : in My_Interfaces.Cursor'Class)
+        return Graph_Iterators.Reversible_Iterator'Class;
+
+    function Iterate_Choice
+           (This : in Parse_Graph;
+            Func : in Choosing_Function)
+        return Graph_Iterators.Forward_Iterator'Class;
+
+
+
+
 private
 
 
+    type Node is new My_Interfaces.Node with null record;
+
     type Cursor is new My_Interfaces.Cursor with null record;
 
+    type Iter_Cursor (Data : not null access Cursor) is null record;
 
     type Parse_Graph is new My_Interfaces.Graph with null record;
 
 
+
+
+    No_Node : constant Node := (My_Interfaces.Node with null record);
+
+    No_Position : constant Cursor := (My_Interfaces.Cursor with null record);
+
+    Empty_Graph : constant Parse_Graph := (My_Interfaces.Graph with null record);
+
+
+
+
+    type Forward_Iterator is new Graph_Iterators.Forward_Iterator with record
+        My_Container : access Parse_Graph;
+        My_Position  : Cursor;
+    end record;
+
+    overriding function First
+           (Object : in Forward_Iterator)
+        return Iter_Cursor;
+
+    overriding function Next
+           (Object : in Forward_Iterator;
+            Place  : in Iter_Cursor)
+        return Iter_Cursor;
+
+    type Reversible_Iterator is new Graph_Iterators.Reversible_Iterator with record
+        My_Container : access Parse_Graph;
+        My_Position  : Cursor;
+    end record;
+
+    overriding function First
+           (Object : in Reversible_Iterator)
+        return Iter_Cursor;
+
+    overriding function Next
+           (Object : in Reversible_Iterator;
+            Place  : in Iter_Cursor)
+        return Iter_Cursor;
+
+    overriding function Last
+           (Object : in Reversible_Iterator)
+        return Iter_Cursor;
+
+    overriding function Previous
+           (Object : in Reversible_Iterator;
+            Place  : in Iter_Cursor)
+        return Iter_Cursor;
+
+
 end Packrat.Graphs;