[Zope3-dev] Use case not covered for translation of message ids

[Godefroid Chapelle]

Hi,

while working at the mountain sprint on the port of message ids to Z2, 
we found out that the following use case is not covered :

<div tal:content="string:My content item is of type ${type_msgid}." />

where type_msgid is a MessageID that a developer did define in Python 
code for instance.

Currently, the message id is not translated : the id itself is 
concatenated to the text in the string expression.

This use case can be seen as wrong : the text "My content item is of 
type" won't be translated.

Ideally the template developer should have written :

<div i18n:translate="">My content item is of type <span 
tal:replace="type_msgid" i18n:name="type" />.</div>

Anyway, in the first case, the developer made his part of the job 
correctly : he said that this value should be translated. So we think 
that even if the template is badly written, the message id should be 
translated.

Please find hereunder a fix to class StringExpr from 
zope/tales/expressions.py that solves this situation by allowing the 
user to see the translation so that he can go and beat the template 
designer ;-)

from zope.i18n.messageid import MessageID


     def __call__(self, econtext):
         vvals = []
         for var in self._vars:
             v = var(econtext)
             if isinstance(v, MessageID):
                 v = econtext.translate(v, domain=v.domain
                        mapping=v.mapping, default=v.default)
             vvals.append(v)
         return self._expr % tuple(vvals)


-- 
Godefroid with Jurgen Kartnaller