Add description to prototype pattern

GiantsLoveDeathMetal · GiantsLoveDeathMetal · commit 87c59f2e56b3 · 2018-06-16T14:00:34.000+01:00
diff --git a/creational/prototype.py b/creational/prototype.py
@@ -2,6 +2,24 @@
 # -*- coding: utf-8 -*-
 
 """
+*What is this pattern about?
+This patterns aims to reduce the number of classes required by an
+application. Instead of relying on subclasses it creates objects by
+copying a prototypical instance at run-time.
+
+This is useful as it make it easier to derive new kinds of objects,
+when instances of the class have only a few different combinations of
+state, and when instantiation is expensive.
+
+*What does this example do?
+When the number of prototypes in an application can vary, it can be
+useful to keep a Dispatcher (aka, Registry or Manager). This allows
+clients to query the Dispatcher for a prototype before cloning a new
+instance.
+
+Below provides an example of such Dispatcher, which contains three
+copies of the prototype: 'default', 'objecta' and 'objectb'.
+
 *TL;DR80
 Creates new object instances by cloning prototype.
 """
