[Zope3-dev] "Sub interface"

[Stephan Richter]

On Sunday 29 February 2004 00:27, Terry Hancock wrote:
> A sub-interface inherits from Interface.Attribute, but
> has an extra property specifying the expected interface
> of the attribute.

For this we have fields. I just checked and you cannot specify the interface 
of a field, but this can be easily done: 

class GeneralField(Field):

    def __init__(self, *args, **kwargs):
          if "interface" in kwargs:
               self._interface = kwargs["interface"]
               del kwargs["interface"]
          else:
               ValueError, "'interface' argument missing."

          super(GeneralField, self).__init__(*args, **kwargs)

    def _validate(self, value):
        try:
            verifyObject(value, self._interface)
        except Invalid, err:
            raise ValidationError("Value does not implement %s"     
                                               %self._interface.name())

Regards,
Stephan
-- 
Stephan Richter
CBU Physics & Chemistry (B.S.) / Tufts Physics (Ph.D. student)
Web2k - Web Software Design, Development and Training