Bill Campbell wrote:
[..]
Thanks Raphael. That works.
Good to know.
Should this then be the same as the ``portal_type'' in the class?
I didn't get this from the Archetypes or ArchGenXML documentation.
Does that mean that the import is not needed (asking before using
the old learn-by-destroying methodology :-).
As I never use ArchGenXML I have no idea what it needs or assumes
nor how you deal with it.
But I agree it can be somewhat confusing as long as you are missing
the big picture.
First, there is Python ;-)
For Python (imports), the name of the class and the module(path)
matters.
Next, there is Zope.
Zope adds the concept of a 'meta type' which may be identical to the
class name but doesn't need to be. In Plone you ususally don't deal
with the meta type unless you turn to the ZMI. There it is used all
over the place.
Then there is CMF.
CMF adds the concept of a 'portal type'. You can have as many different
portal types based on the same Python class and Zope meta type as you
want. The portal type is used to assign content items - well, their
portal type - via having 'factory type information' (FTI) objects
with that very id in the types tool (the 'DynamicType' mixin class
implements this linkage).
Finally, there is Archetypes,
which adds the 'archetype name' to the picture. This gets transfered
to the title of the corresponding FTI objects and is used, e.g., in
the user interface.
Now, the confusion typically arises because often times these four
different things all have the same value (class name == meta type
== portal type == archetype name) so people usually don't need to
know or care and things just work.
For the default content types today, however, the situation
is different, because Plone initially used the implementation
provided by CMFDefault and later switched to using the one
from ATContentTypes. As these are different implementations
of the same concept, their Python classes and (Zope) meta types
have to be different, while their portal types are of course
the same. This is why at the Python level you need to do things
like
from Products.ATContentTypes.content.topic import ATTopic
(class name and path)
while at FTI level, you need to use the more conceptual
portal type
allowed_content_types = ['Topic', ...]
Maybe this clarifies things a bit?
Raphael
PS: quite a while ago I wrote something similar that
Alex turned into a how-to later on
http://plone.org/documentation/how-to/understand-type-distinctions
Maybe someone wants to update this to include the Python level
and the ATCT twist?
Bill
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INTERNET: [EMAIL PROTECTED] Bill Campbell; Celestial Software LLC
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