Am Donnerstag 28 August 2008 23:55:24 schrieb Martin Aspeli: > Hermann Himmelbauer wrote: > > Am Donnerstag 28 August 2008 02:35:28 schrieb Marius Gedminas: > >> On Wed, Aug 27, 2008 at 05:15:48PM -0700, Stephan Richter wrote: > >>> On Wednesday 27 August 2008, Martin Aspeli wrote: > >>>> This means that if the request contains the empty-marker only (no > >>>> selection was made) for a checkbox widget (say), then the return value > >>>> is [], rather than default (NOVALUE). > >>>> > >>>> Is that a bug? I have a custom checkbox widget derived from the > >>>> standard checkbox widget, (z3c.formwidget.query, in fact), and I never > >>>> get any "required missing" exceptions, even when I untick all the > >>>> checkboxes and click OK. > >>>> > >>>> Am I missing something? > >>> > >>> I think you have a point. Have you tried changing the behavior to > >>> return "default" and see what tests fail? If no major failures come out > >>> of this, I would say change it. > >> > >> Wait a second, maybe I'm misunderstanding this, but I certainly oppose > >> any change that would make an unchecked checkbox an error during form > >> validation. > >> > >> A required Bool field can have two values: True or False. One is > >> represented by a checked checkbox, the other by an unchecked checkbox. > >> An unchecked checkbox is not missing input and should not trigger > >> "required missing" errors. > > > > I see this the same way - in my application I have a similar case (Accept > > some policy by a checkbox-click). I solved this simply by checking the > > value in the action handler and raising a WidgetExecutionError if it is > > unchecked. > > The notion of a "required" boolean field is a bit weird anyway. > > I think you *could* interpret it so that a boolean field that's required > really means "you have to tick this box" (e.g. an "I agree to these > terms and conditions" type scenario).
My idea is to look at it bottom-up: Think about schemas without widgets at all, e.g. in a totally different non-zope/form scenario. To my mind, it's obvious, that required="True" means, that some sort of value has to be given and not, that the value has to be of a specific type (e.g. "True" for Boolean). > To put it the other way - how would you have a non-required boolean > field represented by a checkbox? You really need three states then: True > False and None, which you can't get with a checkbox. Well, and then there's the representation of fields by widgets. And, right, it's impossible to provide no value via a checkbox or a radio-box offering "yes/no". And, yes, this somehow obsoletes the "required" constraint. But isn't this perfectly normal for widgets? For instance, a Choice, which is represented by a drop-down widget, will also never return None. Btw., it is possible to have a three-state widget for booleans, such as a drop-down widget, that includes "True/False/None", although it may not make much sense. Best Regards, Hermann -- [EMAIL PROTECTED] GPG key ID: 299893C7 (on keyservers) FP: 0124 2584 8809 EF2A DBF9 4902 64B4 D16B 2998 93C7 _______________________________________________ Zope-Dev maillist - Zope-Dev@zope.org http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
