[Zope3-dev] Proposed widget/schema work for the Rivah sprint (Thursday and Friday this week)

[Garrett Smith]

> I'm uncomfortable with this. Right now, I think fields do too much.
> They have too much application logic.  This would add more.  The whole
> concept of "initial value" seems to be very application dependent.
> Maybe it would be best to just drop the default field altogether
> and introduce adapters for computing initial values in those special
> cases when we need them.

Funnily, I just faced this dilema earlier today. I nearly created an interface like this:

  class IInitialValue(Interface):
      """An interface for obtaining an initial value for an object."""

      def get():
          """Returns the initial value."""

IMO, this is superior to field.initial. E.g.

  zapi.getMultiAdapter((field, context), IInitialValue).get()

Perhaps this pattern could be used for getting an ISource from a field. E.g.

  zapi.getMultiAdapter((field, context), ISource)

 -- Garrett