Model redesign?

Just some thoughts based on earlier model discussions... (These are
just loose thoughts, so Dallas: Don't panic -- we can probably still
use much/most of your code ;)

It seems that we're having problems with the attribute-bound-to-model
design. An alternative has been proposed with special model
registering methods. If we are to drop my MVC design in favour of
something else, I'd rather have things be even simpler, and to make
Proxies even less coupled with models.

So... I'm back to using the event system again (which was my original
idea). Let's (for now) ignore the fact that Attrib.set(...) takes
Option objects as positional arguments, and get to the specifics of
that later. Then my idea works basically as follows:

  >>> btn = Button()
  >>> mdl = NumberModel(name='x')
  >>> link(mdl, btn.set)

Here, when mdl is modified, btn.set will be called. To implement the
controller part of things, Components can be observable as well:

  >>> link(btn, 'update', mdl.set)

Here, of course, mdl.set will be passed lots of attribute/value pairs,
most of which are not interesting at all.

One quirk of this approach is that the set method is passed an event
object. Either we can define some specific functionality to modify the
event objects, or we can make set() accept event objects -- or make it
possible for Option objects to restrict its items (i.e. have an
items() method) and give Event objects the same functionality, and let
the sender restrict what attributes are to be used -- or something...

Quite loose stuff as yet, but the basic idea is to simply use link()
to link observables and observers, and to drop all other MVC
functionality (except including the Model classes as utilities).

-- 
Magnus Lie Hetland        Practical Python          The Anygui Project
http://hetland.org        http://ppython.com        http://anygui.org


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