Support for decorators was proposed for Python in [http://www.python.org/peps/pep-0318.html PEP 318], and will be implemented in Python 2.4.

What is a decorator

A decorator is a software design pattern. Decorators dynamically alter the functionality of a function, method, or class without having to directly use subclasses or change the source code of the function being decorated.

For more information about the decorator pattern in general, see:

• http://wiki.cs.uiuc.edu/patternStories/DecoratorPattern

• http://en.wikipedia.org/wiki/Decorator_pattern

Debate about decorators in Python

The winning syntax as of now uses the '@' symbol, as described in [http://mail.python.org/pipermail/python-dev/2004-June/045516.html this message]. Mark Russell implemented this version. [http://mail.python.org/pipermail/patches/2004-July/015452.html Here] is the message describing the patch he checked in.

There has been a long discussion about the syntax to use for decorators in Python. See for example these threads:

• http://article.gmane.org/gmane.comp.python.devel/61569

• http://www.livejournal.com/users/jcalderone/3913.html

Examples

   1 @classmethod
   2 def foo (arg1, arg2):
   3     ....

Related Resources

See also: MixIns, MetaClasses