On Mon, Jan 19, 2015 at 8:42 PM, Guido van Rossum <guido@python.org> wrote:

On Mon, Jan 19, 2015 at 5:04 PM, Chris Barker - NOAA Federal <chris.barker@noaa.gov> wrote:

I always teach that the @ syntax is a decoration, not a decorator, whereas a decorator is a function that takes a function and returns another function ( usually a customized version of the passed in function). This distinction between decorators and decoration syntax keeps the door open to do just about anything with decorations, but am I the only one that thinks it's a bad idea to have it be for "any old thing we want to hang off a function"?

I think you're the only one who makes this distinction.

No, I'm not -- take a look at any number of tutorial sites, and answers for newbies on SO, etc. I used to teach decorators without making the distinction, and got a lot of confused students. maybe the distinction is only useful for pedagogical purposes, but I introduced it here 'cause it's a bit harder to talk about when a "decorator" can be either a function the behaves a certain way or the @something line in the code.

In common use "decorator" is used to describe both the syntax and the function invoked by the syntax. "Decoration" is never (well, very rarely) used. And calling any function that takes a function and returns one a decorator feels overreaching -- I'd only call it a decorator if it is intended to use with the decorator syntax.

sure -- I'm having a hard time coming up with the word s to describe what I"m talking about as  "proper" decorator. The truth is, you can put any callable that takes at least one argument after that @. And I'm not suggesting that python should enforce anything in particular about that. What I am suggesting is that we should not officially suggest that you should use a decorator for any old thing that doesn't fit the usual sprit of decorators.

A decorator that simply adds stuff to the docstring feels pretty ugly to me, particular if it goes beyond docs to specifying something important about the typing, etc.

Hard to draw a line there, but I  think we should keep the spirit of decorators in mind.

But enough said.