[Zope-CMF] Class based vs TTW for Schemas.

[Lennart Regebro]

Andreas Jung wrote:
> Please explain.

OK. I was planning to think it through and write something consistent, 
but I don't have the time, so this will probably be a bit confused. I'll 
explain with an example:


In CPS, we do the member management through directories. In CPS3, these 
directories are based on CPSSchemas, which makes it possible for us to 
define the schema of a user and then have the directories display this 
schema (just like Archetypes) for each user without any actual member 
objects existing.
I'm not sure if this is possible with Archetypes, maybe it is. But as I 
understand it you create a python class for each schema, which would 
only complicate things. So that is one point.

A next point is that CPS by default sets up a member schema with  first 
name and last name, and such. No problem there. However, the NuxWebMail 
product needs to have a IMAP username and password associated with the 
user. This is simply done by adding these two fields to the schemas in 
the NuxWebMail setup. I don't se how this can be done with a schema 
defined in a python file.

Also, the ttw design of CPSSchemas means that we have a TTW interfaces 
for managing vocabularies, so that a manager can change them. No Python 
hacking, not even fiddling with dictionaries in a skin is needed.


And last, and maybe least, already two years ago I started working 
together with Johan Carlsson on something we had an idea of. Something 
we wanted instead of ZClasses, namely a way to create useful classes 
without programming, or possibly with only very basic simple scripting, 
all TTW. I have often found a need to create simple classes that really 
need almost no programming, just a bunch of properties. For me as a 
programmer that is of course no problem to create a disk based class, 
but for others? I have always felt that ZClasses is supposed to fill 
that slot, but fail, because they are even more complicated to wrap 
their head around than disk based classes. I think CPS Schemas comes 
very close to that vision. You can have a site manager that adds and 
changes classes without having to program python.


Well, that's all I can come up with now.

//Lennart