+
+ //===--------------------------------------------------===//
+ // Iterators.
+ //===--------------------------------------------------===//
+
+ class iterator {
+ typename TreeTy::iterator itr;
+
+ iterator() {}
+ iterator(TreeTy* t) : itr(t) {}
+ friend class ImmutableMap;
+
+ public:
+ value_type_ref operator*() const { return itr->getValue(); }
+ value_type* operator->() const { return &itr->getValue(); }
+
+ key_type_ref getKey() const { return itr->getValue().first; }
+ data_type_ref getData() const { return itr->getValue().second; }
+
+
+ iterator& operator++() { ++itr; return *this; }
+ iterator operator++(int) { iterator tmp(*this); ++itr; return tmp; }
+ iterator& operator--() { --itr; return *this; }
+ iterator operator--(int) { iterator tmp(*this); --itr; return tmp; }
+ bool operator==(const iterator& RHS) const { return RHS.itr == itr; }
+ bool operator!=(const iterator& RHS) const { return RHS.itr != itr; }
+ };
+
+ iterator begin() const { return iterator(Root); }
+ iterator end() const { return iterator(); }
+
+ data_type* lookup(key_type_ref K) const {
+ if (Root) {
+ TreeTy* T = Root->find(K);
+ if (T) return &T->getValue().second;
+ }
+
+ return 0;
+ }