[Python-Dev] method decorators (PEP 318) (original) (raw)

Jack Diederich jack at performancedrivers.com
Fri Mar 26 11:08:32 EST 2004

On Fri, Mar 26, 2004 at 07:10:34AM -0800, Guido van Rossum wrote:

We came to an interesting conclusion (which Robert had anticipated): there are two quite different groups of use cases.

The other group of use cases merely attaches extra bits of metadata to the method, without changing its usage. That is what most C# and Java decorators are used for. I've posted some examples in the 318 threads of both kinds, the function decorators I use tend to change behavior and the class decorators I use tend to be meta-markup.

For class decorators I currently use a work around w/ metaclasses, I don't decorate functions much so I just do it the old fashioned way.

So, anyway, here's a new suggestion (inspired by Robert's proposal): (2) Invent some other notation for setting function attributes as part of the function body, before the doc string even.

For (2) I am thinking aloud here: def foobar(self, arg): @author: "Guido van Rossum" @deprecated pass

I'm agnostic on '@' but this looks like pydoc markup to me, what about

def foobar(self, arg): @author = "Guido van Rossum" @deprecated = True

People will also want to access these, so also consider how this will read:

def foobar(self, arg): @author = "Guido" @email = @author.lower() + '@python.org' # contrived example

I'd be a little worried that new users from other languages would start using '@' as a synonym for 'this' in strange ways. Nothing that can't be remedied with a clue bat.

-jackdied

More information about the Python-Dev mailing list