[squeak-dev] Unloadable preferences in trunk

> Folks -
>
> Not sure if you noticed but we're making steady progress towards safe
> unloading of MVC. I did a second round on preferences in the trunk and
> this time I went for UI dependencies. As a consequence, you will find
> that in the latest trunk image there are only four preference related
> classes left in the System package: Preferences, Preference,
> PragmaPreference, and PreferenceExample.
>
> Gone is PreferencePanel which created a host of dependencies. Gone
> from the System package are the view registries, which have been moved
> into PreferenceBrowser. The internal storage of Preferences was
> slightly changed from holding onto PreferenceViewRegistries to instead
> store a type symbol which happen to be the same type symbols used in
> Pragma preferences.
>
> This has two immediate consequences: First, one can now implement
> preference browser/viewer without having to understand the (rather
> complex) lookup and priority scheme utilized by view registries. All
> you need is something that allows modifying a preference based on the
> type of the preference.
>
> Secondly, pretty much the entire preference machinery can now be
> unloaded in one go simply by getting rid of the PreferenceBrowser
> package. The only thing remaining then are the four aforementioned
> classes.
>
> Cheers,
>   - Andreas
>
>
>
>