+redef class RopeNode
+ super Streamable
+end
+
+redef class Leaf
+
+ redef fun write_to(s) do s.write(str)
+end
+
+redef class Concat
+
+ redef fun write_to(s)
+ do
+ if left != null then left.write_to(s)
+ if right != null then right.write_to(s)
+ end
+end
+
+redef class RopeString
+
+ redef fun write_to(s) do root.write_to(s)
+end
+