[Zope3-dev] RFC: zcml:condition

[Martijn Faassen]

Jim Fulton wrote:
[snip]

> Thoughts?

No objections to this design, but some questions about the decisions 
that went into the design.

Not as powerful as before, which is good. External ZCML processors might 
mostly try to ignore this, though that also depends on how conflicts are 
dealt with -- see my question below.

I'm not sure about the 'verb arguments' construction -- is there a need 
for verbs or is this a YAGNI? Could you list some other potential verbs? 
I can come up with 'nothave', not sure whether I can come up with 
applications for it. :)

'platform' might be a useful verb, perhaps. Then again, you could also 
work this with the semantics for 'have', I think, if you allow for 
featurenames to be specified *before* all ZCML processing starts.

Why the choice to make the verb be part of the attribute value, instead 
of having the verb *be* the attribute? i.e. you could have

zcml:feature

or zcml:hasfeature or zcml:iffeature

or something along those lines.

Another question: How does this impact conflicts? i.e. will conflicts 
still occur with declarations if a piece of ZCML is conditioned out? I 
guess not, as you might want to supply multiple conflicting pieces of 
ZCML. Then again, if you want to do that for feature A and B, you have 
no guarantee both features won't be there at the same time, so that 
might lead to trouble...

Regards,

Martijn