[z3-five] Wrapping Z2 interfaces (maybe, "bride of Frankenzope"?)

[Tres Seaver]

For existing Zope2 applications which already declare and use Zope2 
interfaces, it seems natural to re-use those specifications.  I have a 
utility module (with a handful of tests) which exports 
'fromZ2Interface', a function which introspects a Zope2 interface object 
and synthesizes an "equivalent" Zope 3 interface.

I am currently using it in a scratch product, CMFonFive, to populate the 
'interfaces' module, e.g.:


   from utilities import fromZ2Interface

   from Products.CMFCore.interfaces.CachingPolicyManager \
       import CachingPolicyManager as _IZ2_CachingPolicyManager

   ICachingPolicyManager = fromZ2Interface(_IZ2_CachingPolicyManager)

   del _IZ2_CachingPolicyManager


The amount of noisy boilerplate in that module is painful:  I did take 
the opportunity to rename CMF interfaces, but that is the only real 
"value" the module adds.  I am pondering a ZCML directive which would
remove the need for the boilerplate;  something like:

   <five:bolt-on
 
source="Products.CMFCore.interfaces.CachingPolicyManager.CachingPolicyManager"
     target=".interfaces.ICachingPolicyManager"
     />

Would the utility be useful in Five?  The directive?

Tres.
-- 
===============================================================
Tres Seaver                                tseaver at zope.com
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