Re: Strange behaviour with unknown alternativeNumberingStyle

[Thomas Morley]

Meanwhile I created https://gitlab.com/lilypond/lilypond/-/issues/6507

Am Sa., 31. Dez. 2022 um 19:01 Uhr schrieb Dan Eble <dan@lyric.works>:
>
> On Dec 30, 2022, at 12:10, Thomas Morley <thomasmorley65@gmail.com> wrote:
> >
> > Hi all,
> >
> > please have a look at:
> >
> > \version "2.25.0"
> >
> > {
> >  \override Score.BarNumber.break-visibility = ##(#f #t #t)
> > %  \set Score.alternativeNumberingStyle = #'whatever
> >  b1
> >  \repeat volta 2 { c' c' }
> >  \alternative { d' e' }
> >  f'
> > }
> >
> > As soon as the style-setting is uncommented it behaves like
> >  \set Score.alternativeNumberingStyle = #'number
> > shouldn't an unknown style behave like the default '()?
>
> I don't see documentation or regression tests for anything beyond 'number and 
> 'numbers-with-letters.
>
> Since 
> https://gitlab.com/lilypond/lilypond/-/merge_requests/594#note_477121479,
> Timing_translator chooses the numbers and Bar_number_engraver formats them.  
> Any value of "alternativeNumberingStyle" causes Timing_translator to use the 
> alternative numbering scheme common to both of those styles.

Ok, still a bug, imho.
We should provide a predictable fallback, getting 'number instead is unexpected.

>
> > tl;dr
> > This probably prevents me defining a knew style
> > with a custom engraver
> > as fix for lsr-snippet 1080 "Incrementing bar numbers in volta
> > repeats"
> > https://lsr.di.unimi.it/LSR/Item?id=1080
>
> From the description: "Here is a hack that increments the currentBarNumber 
> property whenever volta repeats occur.  It also offers basic (though limited) 
> support for alternatives."
>
> Do you need a new value for alternativeNumberingStyle?  If you want the 
> behavior arising from leaving alternativeNumberingStyle unset, why not leave 
> it unset and let your custom engraver do the rest?

Yep, that's what I've done. Alas, I feel creating a new style would
have been more elegant.

>
> Besides, the snippet's numbering scheme seems oriented toward the volte in 
> general rather than the alternatives.  It isn't clearly a new kind of 
> alternative numbering.

Well, 'numbers is not that far from the default either.

Cheers,
  Harm

> —
> Dan
>