+/* Returns c-string "s" if n > 1, empty string "" otherwise. */
+#define ESSE(n) ((n) > 1 ? misc::str_esse : misc::str_nil)
+namespace misc {
+
+ extern const char str_esse[];
+ extern const char str_nil[];
+
+ template <typename T>
+ struct address: public std::unary_function<T&, T*> {
+ T* operator()(T& ref) { return &ref; }
+ };
+
+}