Re: Custom percussion style is ignored for the first note when it is a grace note

[Thomas Morley]

Am Mi., 25. Jan. 2023 um 17:54 Uhr schrieb David Kastrup <dak@gnu.org>:
>
> Stu McKenzie <swwsoft@handsmck.com> writes:
>
> > There seems to have been various reports of bugs when the first note
> > is a grace note, but this bug has been in many LilyPond versions to
> > date.
> >
> > When the first note of a drum score has a grace note, LilyPond outputs
> > the default note, rather than the custom percussion style.
> >
> > In this case, \acciaccatura is used to create each grace note - main
> > note combination.
> >
> > Here's a "Tiny example":
> >
> > \version "2.24.0"
> > #(define mydrums '( (hightom default #f 3)))
> > \score {
> >   \new DrumStaff <<
> >     \set DrumStaff.drumStyleTable = #(alist->hash-table mydrums)
> >     \new DrumVoice { \voiceTwo \drummode { \partial 2 \acciaccatura
> > tomh8 tomh4 \acciaccatura tomh8 tomh4 } }
> >   >>
> > }
>
> This is not a bug.  You specify you _want_ simultaneous music by using
> << ... >> and the settings of DrumStaff.drumStyleTable are performed
> _on_ the beat while the grace notes are performed _before_ the beat.
>
> This is _exactly_ as you tell LilyPond you want things to happen.  If
> you want to have things to happen in sequence, you have to write them in
> sequence.
>
> Using { ... } instead of << ... >> here probably gives something closer
> to your expectations.
>
> Now for things that _pervade_ a context rather than switch around, it
> makes sense not to set them at the first time step but generally, by
> using a \with block:
>
> \version "2.24.0"
> #(define mydrums '( (hightom default #f 3)))
> \score {
>   \new DrumStaff \with { drumStyleTable = #(alist->hash-table mydrums) }
>   {
>     \new DrumVoice { \voiceTwo \drummode { \partial 2 \acciaccatura tomh8 
> tomh4 \acciaccatura tomh8 tomh4 } }
>   }
> }
>
> --
> David Kastrup
>

It's unfortunate that we provide an example like:

\new DrumStaff <<
  \set DrumStaff.drumStyleTable = #(alist->hash-table mydrums)
  \new DrumVoice { \voiceOne \up }
  \new DrumVoice { \voiceTwo \down }
>>

as first code example in NR 2.5 Percussion Custom percussion staves.

I've put up https://gitlab.com/lilypond/lilypond/-/merge_requests/1822
to fix the docs

Cheers,
  Harm