[Zope3-dev] Removing hard dependency from zope.i18nmessageid C extension

[Jim Fulton]

Christian Heimes wrote:
> Hi folks!
> 
> With the new i18nmessageid c module in zope.i18nmessageid it is no 
> longer possible to use zope.schema and zope.i18n w/o a c extensions. 
> Although zope.interface has an optimized module in c like 
> zope.i18nmessageid there is also a python only implementation.
> 
> I would like to see such a python only implementation in 
> zope.i18nmessageid, too.

Agreed.  As a general principal, we should have C and Python
versions of things.

 > Hey as far as I can see there *is* already a
> python only implementation in zope.i18nmessageid.messageid. :) I know 
> it's going to be removed in ZopeX3.2 but as long we have it can we 
> please change the zope.i18nmessageid package like I propose?
> 
> old:
> from messageid import MessageID, MessageIDFactory
> from message import Message, MessageFactory
> 
> my proposal:
> from messageid import MessageID, MessageIDFactory
> try:
>     from _zope_i18nmessageid_message import Message
> except ImportError:
>     # c optimization not availabel
>     Message = MessageID
>     MessageFactory = MessageIDFactory
> else:
>     from message import Message, MessageFactory

You need to be more careful:

1. I'm 90% sure that the Python and C versions have
    different APIs.  If this is so, then you need to
    create a new Python implementation with the same
    api as the C version.

2. If message ids are picklable, then you need to arrange
    for the Python and C versions to have the same module
    and class names.  In fact, you need to make sure that
    they have compatible pickles.

Jim

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Jim Fulton           mailto:jim at zope.com       Python Powered!
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