ztm.interfacemanager
====================
ztm.interfacemanager offers functionality to automatically add marker
interfaces to instances of topics (and role players) using their subject
identifier.

  >>> import zope.interface
  >>> import ztm.interfacemanager
  >>> class IArticle(zope.interface.Interface):
  ...     """A marker interface for instances of the topic type Article."""
  ...     ztm.interfacemanager.bind_to_instances_of(u'http://psi.example.com/article')
  ...

The interface is now registered with the InterfaceManager utility.

  >>> cr = zope.component.getSiteManager()
  >>> manager = cr.getUtility(ztm.interfacemanager.interfaces.IInterfaceManager)
  >>> u'http://psi.example.com/article' in manager.topicinterfaces
  True

Now we create a topic map:

  >>> topicmap = ztm.topicmaps.topicmap.TopicMap()

And fill it some content:

  >>> topictype = topicmap.createTopic()
  >>> topictype.addSubjectIdentifier(u'http://psi.example.com/article')
  >>> topic = topicmap.createTopic()
  >>> topic.addType(topictype)
  >>> IArticle.providedBy(topic)
  True

Notice that the interface is not added to the topic type whose subject
identifier is used:

  >>> IArticle.providedBy(topictype)
  False

You can also mark role players:

  >>> class IPlaywright(Interface):
  ...     """A marker for topics playing the author in associations."""
  ...     ztm.interfacemanager.bind_to_players_of(u'http://psi.example.com/playwright')
  ...

Lets fill the topic map with more types needed to create an association:

  >>> person = topicmap.createTopic()
  >>> playwright = topicmap.createTopic(subjectidentifiers=(u'http://psi.example.com/playwright',))
  >>> authorship = topicmap.createTopic()
  >>> work = topicmap.createTopic()
  >>> play = topicmap.createTopic()
  >>> ibsen = topicmap.createTopic()
  >>> ibsen.addType(person)
  >>> heddagabler = topicmap.createTopic()
  >>> heddagabler.addType(play)

And finally the association.

  >>> topicmap.createAssociation(authorship, playwright, ibsen, work, heddagabler) #DOCTEST: +ELLIPSIS
  <Association ...>

Now ibsen should be marked as a playwright. 

  >>> IPlaywright.providedBy(author)
  True
  >>> IPlaywright.providedBy(heddagabler)
  False

.. warning::

  ztm.interfacemanager does not currently follow super-sub type relationships.
  This may be added in the future.

See the `ztm.interfacemanager documentation`_ for more information.

.. _ztm.interfacemanager documentation: http://ztmproject.org/documentation/ztm.interfacemanager