Stephan Richter wrote:
> On Thursday 28 August 2008, Martin Aspeli wrote:
>> I suspect that we just need widget.SequenceWidget in z3c.form to have a
>> special case for len(self.terms)==1, i.e. it's a checkbox with only one
>> option, or maybe a special case for a BooleanField, or indeed have
>> different widgets for Boolean and ICollection fields.
>
> Widgets should not make these sort of decisions. I think this is the
> responsibility of the data converter. I am pretty sure that writing more
> specific data converters will solve our problem.
In the implementation of extract() in the SequenceWidget(), the
extract() method does this:
def extract(self, default=interfaces.NOVALUE):
"""See z3c.form.interfaces.IWidget."""
if (self.name not in self.request and
self.name+'-empty-marker' in self.request):
return []
value = self.request.get(self.name, default)
if value != default:
for token in value:
if token == self.noValueToken:
continue
try:
self.terms.getTermByToken(token)
except LookupError:
return default
return value
It's the 'return []' that's the problem, i.e. it's treating the return
value when empty-marker is in place as something other than the
'default' that the base widget class will use when the field isn't in
the request:
def extract(self, default=interfaces.NOVALUE):
"""See z3c.form.interfaces.IWidget."""
return self.request.get(self.name, default)
I think to get those same semantics for sequence fields, we'll need
something in the extract() method.
I also don't quite understand why we use [] and not NOVALUE, even when
the field isn't required. It seems to me that the BooleanField case is
the special case. In fact, it's somewhat weird that a BooleanField,
which is scalar, should default to using a SequenceWidget.
Martin
--
Author of `Professional Plone Development`, a book for developers who
want to work with Plone. See http://martinaspeli.net/plone-book
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