[Zope3-dev] Re: zcml questions

[Philipp von Weitershausen]

Tres Seaver wrote:
>>> How should I do things such that they can do that?
>> I'm just wondering whether you really need the disabling feature.
> 
> I've wanted it.

Okay :).

> My major beef with the way we are *using* ZCML now is
> that we expect package authors to provide policy-laden configuration for
> their packages ("sensible defaults") but provide no means for the admin
> to reuse that configuration selectively;  their only realy choice is to
> *copy* the configuration and edit it.

True.

> I argued *long* ago (after the first ZC-internal Zope3 sprint, I think)
> that the '<include>' directive should be allowed to be complex, with
> subelements like '<except>' or '<only>' to pull in specific directives.
>  Such a practice would require either that we have XPath support
> available, or else that we come up with a way to mark the directives
> (e.g., a 'zcml:id' attribute).

Well, we already sort of that this marking with "features" + 
zcml:condition. But <except> and <only> could be more powerful wrt 
packages, modules, or even classes and interfaces.

> It would *also* require that we
> implement the "no side-effects during parsing" policy (my other favorite
> "dead horse" in arguments about ZCML's implementation / usage).

Yup. I think there are very little side effects currently. I can't think 
of one off of the top of my head, to be honest (but I'm sure there are).