+private class BinTreeMapIterator[K: Comparable, E]
+ super MapIterator[K, E]
+
+ var tree: BinTreeMap[K, E]
+ var current: nullable BinTreeNode[K, E] = null
+
+ init do current = tree.first_node
+
+ redef fun is_ok do return not current == null
+ redef fun next do current = current.next
+ redef fun item do return current.value
+ redef fun key do do return current.key
+end