[Zope-dev] Two small convenience suggestions for zope.interface and zope.component

[Marius Gedminas]

On Wed, Apr 01, 2009 at 10:56:30PM +0800, Martin Aspeli wrote:
> Tres Seaver wrote:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> > 
> > Martin Aspeli wrote:
> >> Hi,
> >>
> >> I'd like to add support for the following:
> >>
> >> 1) Provider decorator:
> >>
> >>   @provider(IFoo)
> >>   def some_function(context)
> >>       pass
> >>
> >> This is an alternative to doing a separate alsoProvides() on the function.
> >>
> >> 2) An interfaceProvides directive:
> >>
> >>
> >>   class IFoo(Interface):
> >>       interfaceProvides(ISomeMarker)
> >>
> >> This is alternative to doing alsoProvides() on the interface.
> >>
> >> The reason for this is that currently, you have to put those 
> >> alsoProvides() lines after the function or interface. This makes them 
> >> difficult to find if the bodies of the functions or interfaces are long, 
> >> and goes against the convention of having the "what is this" information 
> >> at the top of the entity.
> >>
> >> I can probably help implement this. Any thoughts?
> > 
> > You should probably add a "class decorator" 'interfaceProvider', as
> > well, because the "in-suite" versions are problematic for 2to3
> > conversion (IIRC what Lennart said yesterday).
> 
> I'm not sure I understand what you mean by that. Can you show an example?

It's a Python 2.6/3.0 feature:

    from zope.component import adapter
    from zope.interface import implementer

    @adapter(IFoo)
    @implementer(IBar)
    class MyClass(object):

        def __init__(self, context):
            self.context = context
            ...

which translates to the obvious

    class MyClass(object):

        def __init__(self, context):
            self.context = context
            ...

    MyClass = implementer(IBar)(MyClass)
    MyClass = adapter(IFoo)(MyClass)

assuming I got the application order right.

I now also wonder if adapter()/implementer() would work when called with
classes rather than functions...?

Marius Gedminas
-- 
http://pov.lt/ -- Zope 3 consulting and development
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