Apparently I wasn't very clear. My intention was to develop this in Python (I've created a grand total of 1 ZClass so far in my life, and that was solely to figure out how to add properties to my python code :) ). Note: I already implemented everything I need personally as a Python module and went on with my work :) . In reading the interfaces Wiki, it seems as though there is an artificial distinction between PropertyManager and PropertySheet-based objects. For instance, my current project has defined a PropertyManager-like interface base class using the PropertySheet interfaces, so that from that base class either mechanism can be used.

From this point, it is a fairly trivial idea to consider replacing the original PropertyManager mechanism with a PropertySheets-based mechanism (keeping the same interface and semantics as PropertyManager) (the advantage to this is to allow all PropertyManager objects to use the more advanced property types and support mechanisms, while reducing the total amount of code). The question of how to implement/re-implement PropertySheets, seems to be the most important one.

A global registry works, but is limited. Allowing for simple sub-classing of PropertySheets and using, for instance, attribute lookup on the individual PropertySheet would work, and allows for locally relevant data types, customised input for individual sheet types etc. The problem with this approach is that the workings of the PropertySheet class have suddenly become something which must be understood to work with custom data types (that is, one more piece of information to add to the Zen of Zope (this is, compared to the total Zen, not huge, but the mental load of grokking Zope is already quite high)). RIPP looks capable, but is currently very young, and will not likely support creating a PropertyManager/PropertySheet interface. This is probably "the future", but is not likely to support "the past". Incidentally, knowing about the Wiki would have been a great help these last few months. Why is the interfaces Wiki table of contents not linked directly off the documentation page? And why are Wiki's not indexed (do a search on www.zope.org for PropertyManager and you only come up with one reference). Sure, indexing a Wiki might be intensive, but the information is, well, important :) . I will consider creating a new Wiki, though I am rather short of time (too long spent spelunking the depths of Zope). It might be simpler to provide another implementation (using PropertySheet attribute look up instead of a global registry) and solicit comments on that. Enjoy yourself, Mike -----Original Message----- From: Michel Pelletier [mailto:michel@digicool.com] Sent: Thursday, May 04, 2000 11:21 PM To: Mike Fletcher Cc: Zope Development (E-mail) Subject: Re: [Zope-dev] Adding your own (complex) data types to property pages: example and problems...nd problems... ... I think it would be better to develop objects like this in Python. There is no clear benefit to using ZClasses for this. There is a clear benefit in using a ZClass to provide a user interface and subclasses a very specialized Python class that does all the heavy lifting. ... Doing this right would require some deep discussion. I suggest creating a Wiki on the zope site and soliciting comments. You may want to review the Interfaces Wiki first, particulary some very recent documentation written by Brian Lloyd. http://www.zope.org/Members/michel/Projects/Interfaces/Properties Let us know how useful this documentation is for you. -Michel