template<class T> struct Array;
template<class T> struct sstack;
template<class T,class K> struct Assoc;
+template<class K, class V> struct Hash_table;
+template<class K, class V> struct Hash_table_iter;
+template<class T> struct Dictionary_iter;
template<class T> struct Dictionary;
template<class T> struct Dictionary_iter;
template<class T> struct List;