--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/itoolstack.d	Wed May 13 15:42:39 2009 +0930
@@ -0,0 +1,18 @@
+module itoolstack;
+
+interface IToolStack {
+    void push(Tool tool);
+    void pop();
+    void replace(Tool tool);
+}
+
+abstract class Tool : ICanvasEventHandler {
+    /*
+    abstract bool is_sticky();
+    abstract bool is_replaceable();
+    */
+
+    abstract void start(IToolStack tool_stack);
+    abstract void stop(IToolStack tool_stack);
+}
+