Add references to other languages

pep-0455.txt

@@ -228,6 +228,34 @@ Several modules in the standard library use identity lookups for object
 memoization, for example ``pickle``, ``json``, ``copy``, ``cProfile``,
 ``doctest`` and ``_threading_local``.
 
+Other languages
+---------------
+
+C# / .Net
+^^^^^^^^^
+
+.Net has a generic ``Dictionary`` class where you can specify a custom
+``IEqualityComparer``: http://msdn.microsoft.com/en-us/library/xfhwa508.aspx
+
+Using it is the recommended way to write case-insensitive dictionaries:
+http://stackoverflow.com/questions/13230414/case-insensitive-access-for-generic-dictionary
+
+Java
+^^^^
+
+Java has a specialized ``CaseInsensitiveMap``:
+http://commons.apache.org/proper/commons-collections/apidocs/org/apache/commons/collections4/map/CaseInsensitiveMap.html
+
+It also has a separate ``IdentityHashMap``:
+http://docs.oracle.com/javase/6/docs/api/java/util/IdentityHashMap.html
+
+C++
+^^^
+
+The C++ Standard Template Library features an ``unordered_map``
+with customizable hash and equality functions:
+http://www.cplusplus.com/reference/unordered_map/unordered_map/
+
 
 Copyright
 =========