Re: [imp-dev] "Interesting" case of dynamic language registration

["Robert M. Fuhrer" <rfuhrer@xxxxxxxxxxxxxx>]

[ This conversation also took place on Bugzilla bug Bug 331751]

[ Ooh, the meta-ness of all of this is giving me chills. :-) You want to extend the
extension mechanism... ]

This sounds entirely reasonable to me. In essence, given that we already
support dynamically registering languages, you now need a way to trigger that
early enough at startup.

Here's my first-cut proposal:

Let's create an extension point for the following interface:

  public interface LanguageRegistrar {
      public void registerLanguages(LanguageRegistry registry);
  }

This would be called by the LanguageRegistry after the normal registration
process is complete.

Sound good?

==============

BTW, I don't know that the following helps any, but I've recently committed
changes to support dynamic language registration when bundles are
activated/deactivated. I've been using this as part of my work on resuscitating
the source formatting rule editor. The editor can now be run in the same
workbench as the rest of IMP!

Seems to work pretty well, though I still have to fix a bug or two in some code
that asks the PDE for all the defined extensions (installed +
workspace-resident).

On Dec 2, 2010, at 3:53 PM, Jurgen Vinju wrote:

Hi,

I'm using LanguageRegistry.registerLanguage(...) to dynamically extend
Eclipse with editors for new languages. The extension points of such
languages are implemented by some "multiplexing" instances of the IMP
services that dynamically find the right implementation for each
editor, based on the language name and some lookup table. These
implementations are provided by Rascal programs.

So far so good ;-) This all works fine when you're running Eclipse and
you don't quit it.

Now when I quit Eclipse and start it up again, the editors for those
dynamically registered languages might still be there. However, since
their language is not registered by an IMP extension point, there is
no language registered for those editors and NullPointerExceptions
start jumping at you from all parts of the UniversalEditor :-(

The question is: where would you add some code that can re-register
those languages, just in time before the UniversalEditors that are
still open will start complaining about missing languages? I don't
think there is a default Eclipse way to do it, and UniversalEditor
does not provide a service for it either. Your advice is much
appreciated. (I really can't/shouldn't/won't add extension points for
those languages). Is there a simple solution?

Cheers,

Jurgen

Cheers,

 - Bob