zopefoundation/zope.schema — pull request #5 by jfroche (2014-01-17 17:57:02+00:00)
Title: Add field events

Enable the possibility to register event on zope schema fields.
This enable to register subscribers that get information about the previous and new value once a field has been updated (model needs to use fieldproperty).
This work is done together with https://github.com/zopefoundation/zope.schemaevent to avoid dependency on zope.component