Stéphane SOPPERA <stephane.sopp...@wanadoo.fr> writes:
> I observed a strange behavior with a /repeat unfold/ inside a /repeat
> volta/ with /alternatives/. See the attached /bug_repeat__ok.ly/ for
> full source.
>
> Using Lilypond 2.24.1:
>
> \repeat volta 2 {
> %% Here we repeat three times the same music.
> * \relative { c'4 e g r } |**
> ** \relative { c'4 e g r } |**
> ** \relative { c'4 e g r } |*
> \alternative {
> \volta 1 \relative { b4 d f g | }
> \volta 2 \relative { b4 d g <c, e g> | }
> }
> }
>
> works as intended, but:
>
> \repeat volta 2 {
> %% Here we replaced the repetition with an `unfold` repeat.
> * \repeat unfold 3 { \relative { c'4 e g r } | }*
> \alternative {
> \volta 1 \relative { b4 d f g | }
> \volta 2 \relative { b4 d g <c, e g> | }
> }
> }
>
> fails. The measure 5 appears before measure 4, the volta is misplaced
> and alternatives are lost (see /bug_repeats__ok.pdf/).
>
> To fix the issue I can put the /repeat unfold/ inside curly brackets:
>
> \repeat volta 2 {
> %% Here we put the `unfold` repeat inside curly braces.
> * { \repeat unfold 3 { \relative { c'4 e g r } | } }*
> \alternative {
> \volta 1 \relative { b4 d f g | }
> \volta 2 \relative { b4 d g <c, e g> | }
> }
> }
>
> Any idea why Lilypond behaves this way? Am I missing something?
It is a consequence of syntax compatibility to previously when
\alternative could follow a \repeat rather than be inside of its body.
So the last music before an in-\repeat \alternative must not be a
\repeat without \alternative or it will sweep up the \alternative for
itself. As you noticed, braces are the proper workaround.
--
David Kastrup
