Add description to the flyweight pattern

GiantsLoveDeathMetal · GiantsLoveDeathMetal · commit e3228c37fcde · 2018-07-14T15:26:43.000+01:00
diff --git a/structural/flyweight.py b/structural/flyweight.py
@@ -2,6 +2,21 @@
 # -*- coding: utf-8 -*-
 
 """
+*What is this pattern about?
+This pattern aims to minimise the number of objects that are needed by
+a program at run-time. A Flyweight is an object shared by multiple
+contexts, and is indistinguishable from an object that is not shared.
+
+The state of a Flyweight should not be affected by it's context, this
+is known as its intrinsic state. The decoupling of the objects state
+from the object's context, allows the Flyweight to be shared.
+
+*What does this example do?
+The example below sets-up an 'object pool' which stores initialised
+objects. When a 'Card' is created it first checks to see if it already
+exists instead of creating a new one. This aims to reduce the number of
+objects initialised by the program.
+
 *References:
 http://codesnipers.com/?q=python-flyweights
 
