implement the helper IntToType template

src/core/int-to-type.h

@@ -0,0 +1,19 @@
+#ifndef INT_TO_TYPE_H
+#define INT_TO_TYPE_H
+
+namespace ns3 {
+
+/**
+ * This trivial template is extremely useful, as explained in
+ * "Modern C++ Design", p29, section 2.4, 
+ * "Mapping Integral Constants to Types"
+ */
+template <int v>
+struct IntToType
+{
+  enum {value = v};
+};
+
+} // namespace ns3
+
+#endif /* INT_TO_TYPE_H */

src/core/wscript

@@ -95,5 +95,6 @@ def build(bld):
         'composite-trace-resolver.h',
         'array-trace-resolver.h',
         'trace-doc.h',
+        'int-to-type.h',
         ]