Implementation of the "Singleton" design pattern. The singleton pattern is a property of a type (yes TYPE, not class) to have at most one single object created at runtime for the corresponding type.

Usage: insert SINGLETON, that's all.

For examples, look at the tools cluster of SmartEiffel.

WARNING: double-check if the object is really a singleton is the conceptual sense.

         Singleton pattern is often used in wrong place. See for example:
         http://www.theagiledeveloper.com/articles/2005/03/03/singleton-overuse-disclaimer
         http://blogs.msdn.com/scottdensmore/archive/2004/05/25/140827.aspx
         http://www.softwarereality.com/design/singleton.jsp
         or search "Singletonitis" or "singleton overuse".