1 files changed, 47 insertions, 0 deletions
diff --git a/omegalib/omega_lib/include/basic/Collection.h b/omegalib/omega_lib/include/basic/Collection.h
new file mode 100644
index 0000000..c7e4eef
--- /dev/null
+++ b/omegalib/omega_lib/include/basic/Collection.h
@@ -0,0 +1,47 @@
+#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;
+
+    virtual int index(const T &) const = 0;  // Y in X --> X[X.index(Y)] == Y
+};
+
+} // 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 
+