Added Iterate_By function for custom iteration

1 files changed, 40 insertions, 0 deletions

diff --git a/src/directed_graphs.ads b/src/directed_graphs.ads
index d31b7c7..3154f75 100644
--- a/src/directed_graphs.ads
+++ b/src/directed_graphs.ads
@@ -670,6 +670,21 @@ package Directed_Graphs is
             Position  : in Cursor)
         return Graph_Iterator_Interfaces.Reversible_Iterator'Class;
 
+    type Choice_Function is access function
+           (Position : in Cursor)
+        return Cursor;
+
+    type Filter_Function is access function
+           (Position : in Cursor)
+        return Boolean;
+
+    function Iterate_By
+           (Container : in Graph;
+            Start     : in Cursor;
+            Chooser   : in Choice_Function;
+            Filter    : in Filter_Function := null)
+        return Graph_Iterator_Interfaces.Forward_Iterator'Class;
+
     function First
            (Container : in Graph)
         return Cursor;
@@ -963,6 +978,31 @@ private
 
 
 
+    type By_Iterator is new Ada.Finalization.Controlled and
+        Graph_Iterator_Interfaces.Forward_Iterator with
+    record
+        Container : Graph_Access;
+        Start     : Cursor;
+        Chooser   : Choice_Function;
+        Filter    : Filter_Function;
+    end record
+    with Disable_Controlled => not Impl.T_Check;
+
+    overriding procedure Finalize
+           (Object : in out By_Iterator);
+
+    overriding function First
+           (Object : in By_Iterator)
+        return Cursor;
+
+    overriding function Next
+           (Object   : in By_Iterator;
+            Position : in Cursor)
+        return Cursor;
+
+
+
+
     generic
         type Base_Type is private;
         type Array_Type is array (Positive range <>) of Base_Type;