[Python-Dev] Re: Python-Dev Digest, Vol 8, Issue 107

[Michel Pelletier]

On Wed, 2004-03-31 at 16:23, Phillip J. Eby wrote:

> >The current system with no syntax is equally usable, what's gained
> >functionally?
> 
> It's not equally usable.  It is 1) considerably more verbose, particularly 
> in Bob's use case of long function names, and 2) hard to spot by a reader 
> who's skimming to get an overview of a class or module.

Both true.  Perhaps I should have said functionally equal.  The proposed
syntax is more usable from a syntax perspective, I agree, but offers no
more "use" once you have the object in hand, so to speak.  The
aesthetics is another matter I've already voiced my opinion on.

> >Another discussion point occurred to me regarding interfaces and
> >projects that use them heavily like Zope, Twisted, PEAK etc.  Has the
> >decorator syntax as proposed been evaluated in the light of these
> >interfaces (and any future native language support for them), whose
> >methods have no body to interpose between the definition and decorators
> >as they exist now?  I've seen the "Large Body" argument use several
> >times in defense of the decorator syntax being before or above the
> >definition.
> 
> I have seen virtually no use of decorators on interface methods in the 
> frameworks you mention.  In fact, I can't recall ever having seen a single 
> use of decorators on interface methods.  That's probably simply because the 
> cost of using decorators is too high to waste on anything that's not part 
> of the implementation,

I think there must be *some* decorators valid for interfaces.  What
about proposed decorators like "synchronized"?  Are these part of the
interface?  Or something equivalent to Java's "throws", arguably a
decoration and arguably part of a method's interface.  What about
decorations that can *never* be used in an interface, like
"classmethod"?  Would an error be raised if you tried to decorate an
interface method with a classmethod decorator? 

I don't think any of these things refute or validate the need for
special syntax, I just wonder if it's been thought about enough, and
that goes way beyond the syntax.

-Michel