Re: Figured-Bass Bug Lilypond 2.9.18 on Windows

[Erik Sandberg]

On Friday 22 September 2006 13:06, Han-Wen Nienhuys wrote:
> Trent Johnston wrote:
> > Figures were able to placed above rests but in recent versions these are
> > now ignored. The figured is excepted (ie. lilypond doesn't complain) but
> > there is no figure printed in the output.
>
> I think the problem is that due to Erik's stream changes in
> 2.9.something, now both Rest_engraver and Figured_bass_engraver listen
> to rest-events. The old behavior of \context FiguredBass was to cancel
> any running bassfigure (continuation line) when a rest was encountered.
>
> When adding the bass figures to the Staff, rests would be caught by the
> normal Rest_engraver. Now both the rest_engraver and the
> figured_bass_engraver catch the rest-event. I could switch off the
> 'terminate  continuation on rest' feature, but that would have other
> compatibility repercussions.
>
> Erik, please advise on a strategy.
hm, we want the engraver to listen to rests only if it's part of a Staff 
context, right?

One solution would be to create one class figured-bass-engraver, without a 
rest listener, and then create a subclass staff-figured-bass-engraver, which 
adds the listener.

If you don't like translator subclassing, then I'd suggest a simple hack, like 
checking for context ()->is_alias ("Staff") before doing anything in 
Figured_bass_engraver::listen_rest.

Speaking of which: I find is_alias a bit confusing; e.g., the alias 'Voice 
usually means it's a context you can align lyrics to. Why don't we rename 
that alias to 'LyricAlign? The alias name 'Voice confuses me because it's 
similar to a context name.

-- 
Erik