add-grob-definition (was: measure counter engraver)

[Pavel Roskin]

On Mon, 23 Apr 2012 21:01:10 -0500
David Nalesnik <address@hidden> wrote:

> Hi all,
> 
> I've been experimenting with a way to create a measure-counter (issue
> 2445), and I've come up with the attached Scheme engraver.  The music
> within a count doesn't need to be repeated to use it.
> 
> This creates a new grob, MeasureCounter, which you can override in
> various familiar ways.

I was surprised that it's possible to create new grobs in Scheme!  I
looked for that functionality while writing cross-staff stem support
and could not find it.

I see that you copied add-grob-definition from scheme-text-spanner.ly.
I believe add-grob-definition is so important that it should be a part
of the Lilypond core.  That's the only way to define a new grob in
Scheme, and it gets copied from one snippet to another!

I think the best place for add-grob-definition would be
scm/translation-functions.scm next to make-engraver.

I've opened an issue for that:
http://code.google.com/p/lilypond/issues/detail?id=2503

-- 
Regards,
Pavel Roskin