#5031 Bar numbering in volta repeats: add option to count once or as often as played

[Simon Albrecht]

There are different ideas of bar numbering: counting bars as written or as played/heard. In other words: volta repeats might be counted only once or as often as they are played. LilyPond currently supports only the former (with alternatives already fixed as of issue 2059), but the latter is used by respectable publications such as the Neue Bach-Ausgabe (1) and I’d like for Lily to support it as well.

Attached is a sketch of what it should look like.

(1) (though not in entirety)

[Simon Albrecht]

Rough sketch at user interface:

\set Score.voltaBarNumbering = #'()
\set Score.voltaBarNumbering = #'identical
\set Score.voltaBarNumbering = #'alternative
\set Score.voltaBarNumbering = #'sequential

Of which the first through third would replace the current

\set Score.alternativeNumberingStyle = #'()
\set Score.alternativeNumberingStyle = #'numbers
\set Score.alternativeNumberingStyle = #'numbers-with-letters

and the fourth would be as proposed in this issue.

It would have to be discussed of course if renaming the context property altogether would be too disruptive, though I think it’s ultimately easiest this way.

[Valentin Villenave]

Possible dupe of issue 3038. Though Simon’s proposal does look quite nice.

[Simon Albrecht]

The two issues are unrelated, since 3038 talks about \repeat unfold.

[Valentin Villenave]

Although not as elegant as the proposed implementation, I’ve uploaded a rough workaround as http://lsr.di.unimi.it/LSR/Item?id=1080