Re: Chromatic clashes

[Lukas-Fabian Moser]

Hi Jean,

> > \version "2.22.0"
> >         
> >         
> >         { <c' cis'> 4 }
> >         
> >         
> >         [...]
> >         
> >         (1) Do you folks agree that the default behaviour qualifies as a
> >         bug?
> >         
> >         
> >       
>       Indeed. There is also an ugly-looking dependence on the input
>       order:
>       
>       
>       { <cis' ces'> cis' }
>       
>       { <ces' cis'> cis' }
>       
>       
>       We should probably have a special case when there are several
>       accidentals in the same staff position. I suggest to open an issue
>       on GitLab.
>       
>

Ok, thanks - will try! 

> >         
> >         For what it's worth, I think I found a not-quite-easy way for
> >         (2), which I'm happy to share of course (see below), but I am
> >         doubtful that this is the most elegant solution...
> >         
> >         
> >       
>       At any rate, that's pretty much how I'd do it personally.
>       
>

After posting my engraver yesterday, I noticed some unforeseen behaviour that gave me an idea for a possible addition to your excellent tutorial on https://extending-lilypond.readthedocs.io/ (which I unfortunately only today had time to skim through). Namely:

The engraver I posted yesterday collects notes across all voices or staves, for instance in situations like

<<
  \new Staff { c' }
  \new Staff { cis' }
>>

While this might actually be desirable (at least I tell my students never ever to produce

since nobody knows if the clash is intended or not), I was surprised that it did so. That's how I found out that if I wrap the engraver in a (lambda (ctx) .... ) construct, then it seems to work independently for each voice context, even if it's \consist'ed to all Voices or Staves in the \layout {} block.

Maybe that would be an interesting addition to your engraver tutorial?

And while we're at it, here's another question: It turns out it's possible to add note-event properties like force-accidental inside the process-music hook. But when I tried to change the _pitch_ of a note at this stage, there was no effect. I _can_ change the pitch of a note-event in the note-head listener, but that's too early in my use case (since I need to know all simultaneous pitches).
So, in which parts of an engraver do I still have the opportunity to change pitches?

Lukas