[Dev] Revisiting the stamping architecture

[Bryan Stearns]

I've got bug 2117 assigned to me ("3rd party parcels can easily foul up 
stamping")..

http://bugzilla.osafoundation.org/show_bug.cgi?id=2117

I'm planning my 0.6 work, but I don't think we've settled on a solution 
to this issue (and I'm not even sure that we need to). I've added the 
comment below to the bug:

>The original report said that it's possible for developers to misunderstand how
>to implement extensions to our content model, by subclassing Item (or
>ContentItem, or ChandlerItem, whatever) instead of creating a Mixin that holds
>just their thing's attributes.
>
>Phillip makes interesting suggestions about a way to significantly rethink the
>content model: that is, to do stamping by adding references to the
>formerly-mixin class instead of doing actual mix-in merging to build a new type,
>but I don't see how this new arrangement fixes the original problem:
>- there's still a developer documentation issue about what you need to create to
>add your own new thing
>- it complicates things by requiring a new attribute/method lookup mechanism to
>traverse the ActionItems and ObjectItem, or requires special lookup calls for
>anyone who wants to use the them.
>- it's not clear that the new generality would give us enough control to
>implement Mimi's rules for how stamped types interact (that is, we'd still need
>the same special-cases at stamping time).
>- it doesn't solve the issues that Lisa brings up in the email thread, relating
>to exporting of stamped items to iCalendar servers.
>
Rather than have a design discussion in bugzilla ;-), I'm reopening the 
discussion here: Phillip, Lisa, Content-model folks -- your thoughts?

...Bryan