1 files changed, 43 insertions, 0 deletions
diff --git a/lib/omega/include/basic/Collection.h b/lib/omega/include/basic/Collection.h
new file mode 100644
index 0000000..80ddf48
--- /dev/null
+++ b/lib/omega/include/basic/Collection.h
@@ -0,0 +1,43 @@
+#if !defined Already_Included_Collection
+#define Already_Included_Collection
+
+namespace omega {
+  
+template<class T> class Iterator;
+template<class T> class Any_Iterator;
+
+
+//! protocol for any kind of collection
+template<class T> class Collection {
+public:
+    virtual Iterator<T> *new_iterator() = 0;
+    virtual Any_Iterator<T>   any_iterator()     { return Any_Iterator<T>(new_iterator()); }
+
+    virtual int size() const = 0;
+};
+
+
+/*!
+ * protocol for collections whose elements are ordered
+ * by the way they are entered into the collection, and
+ * whose elements can be accessed by "index"
+ *
+ * note that the implementation need not be a linked list
+ */
+template<class T> class Sequence : public Collection<T> {
+public:
+    virtual const T &operator[](int) const = 0;
+    virtual       T &operator[](int)       = 0;
+
+    /*! Y in X --> X[X.index(Y)] == Y */
+    virtual int index(const T &) const = 0;  };
+
+} // namespace
+
+#define instantiate_Collection(T)	template class Collection<T>; \
+					instantiate_Any_Iterator(T)
+#define instantiate_Sequence(T) 	template class Sequence<T>; \
+					instantiate_Collection(T)
+
+#endif 
+