[Devel] What is a feature? (extension_data)

[David Robillard]

Hi all,

The current release of LV2 has some confusing comments about
extension_data.  It's not really clear just what a "feature" is, and how
the plugin data would indicate that the plugin provides some
extension_data (despite the comment saying that they must).

So, we need a predicate for hasExtensionData.  This raises the question:
is this a "feature"?  Our current feature stuff, and LV2_Feature, is all
about the host passing things to the plugin.  Maybe it would be
confusing to overload that term for extension_data?

Maybe there should be subclasses of Feature, HostFeature and
PluginFeature?  (This would suggest extension_data should have been
called feature or plugin_feature, but whatever)

Note that none of this affects the plugin API, but we need a sane way to
describe these things in data files.

I think I am going to hold off on the initialization stuff, so this is
the sticking point for 4.2.  Opinions welcome.

Thanks,

-dr