[Zope3-dev] Recursive containment constraints

[Dominik Huber]

Month ago I read the contenttype part of stephan's book. at that time he
used
setTaggedValue to solve recursive containment constraints:

    43  IMessage['__setitem__'].setTaggedValue('precondition', 
    44
ItemTypePrecondition(IMessage)) 
    45  IMessage.setTaggedValue('__parent__', Field( 
    46      constraint=ContainerTypesConstraint(IMessageBoard,
IMessage)))

Today I wanted to use the setTaggedValue('__parent__', Field(...))
approach but it
seems not work anymore. Is that right?

    >>> '__parent__' in IMessage.names('all')
    False

The new version of the book solves this problem with two indepentent
interfaces IMessage
and IMessageContained. Is that the 'official' pattern people should
follow?

Thanks for the responses!

Regards,
Dominik Huber