Using 'apply' as a decorator, to define constants

[Jonathan Gardner]

On Aug 21, 9:09 am, alex23 <wuwe... at gmail.com> wrote:
> On Aug 21, 11:36 pm, Jonathan Fine <jf... at pytex.org> wrote:
>
> class ColourThing(object):
>     @apply
>     def rgb():
>         def fset(self, rgb):
>             self.r, self.g, self.b = rgb
>         def fget(self):
>             return (self.r, self.g, self.b)
>         return property(**locals())
>

This is brilliant. I am going to use this more often. I've all but
given up on property() since defining "get_foo", "get_bar", etc... has
been a pain and polluted the namespace.


> Unfortunately, apply() has been removed as a built-in in 3.x. I'm not
> sure if it has been relocated to a module somewhere, there's no
> mention of such in the docs.

    apply = lambda f: f()

It's one of those functions that is easier to define than import.


> Why I've personally stopped using it: I've always had the impression
> that decorators were intended to provide a convenient and obvious way
> of augmenting functions. Having one that automatically executes the
> function at definition just runs counter to the behaviour I expect
> from a decorator. Especially when direct assignment... foo = foo
> () ...is a far more direct and clear way of expressing exactly what is
> happening.
>

If anyone reads the decorator and doesn't think "this thing below is
defined as the result of this decorator function" then they don't
understand decorators at all.