[Zope-dev] z3c.formwidget.query - incorrect interface implementation?

24 Aug 2008

      Hi,

I'm trying to build a widget that allows for auto-complete of items in a 
vocabulary, but also allows additional (string) values to be added. To 
understand how that works, I am digging into z3c.formwidget.query, and 
it looks to me like it's making incorrect assumptions about its own 
interfaces.

In its interfaces.py, we have:

from zope.schema.interfaces import ISource, IVocabularyTokenized
class IQuerySource(ISource, IVocabularyTokenized):
     def search(query_string):
         """Return values that match query."""

so, an IQuerySource is an ISource, which is:

class ISource(Interface):

     def __contains__(value):
         """Return whether the value is available in this source
         """

and also an IVocabularyTokenized, which is:

class IBaseVocabulary(ISource):

     def getTerm(value):
         """Return the ITerm object for the term 'value'.

         If 'value' is not a valid term, this method raises LookupError.
         """

# BBB vocabularies are pending deprecation, hopefully in 3.3
class IIterableVocabulary(Interface):

     def __iter__():
         """Return an iterator which provides the terms from the 
vocabulary."""

     def __len__():
         """Return the number of valid terms, or sys.maxint."""

class IVocabulary(IIterableVocabulary, IBaseVocabulary):
     """Vocabulary which is iterable."""

class IVocabularyTokenized(IVocabulary):

     def getTermByToken(token):
         """Return an ITokenizedTerm for the passed-in token.

         If `token` is not represented in the vocabulary, `LookupError`
         is raised.
         """

First of all, it seems strange then that IQuerySource should explicitly 
need to say it's derived from ISource since IVocabularyTokenized already 
promises that.

However, more importantly, in the README.txt of z3c.formwidget.query we 
have this:

   ...     def getTermByValue(self, value):
   ...         return self.vocabulary.by_value[value]

and similarly, in widget.py:

         map(terms.add,
             map(source.getTermByValue,
                 filter(lambda value: value and value not in values, 
selection)))

If I'm not reading this wrong, it seems to me that z3c.formwidget.query 
is using getTermByValue() (which I can't find anywhere else) instead of 
getTermByToken() as defined by IVocabularyTokenized.

Is this correct?

Martin

-- 
Author of `Professional Plone Development`, a book for developers who
want to work with Plone. See http://martinaspeli.net/plone-book

[Zope-dev] z3c.formwidget.query - incorrect interface implementation?

Martin Aspeli