Re: Tricky repeat structure for "32-bar form" AABA

[Joel C. Salomon]

Looks like the function version works.

Interestingly, swapping `\after \duration $A \volta 2 \fine` with `\volta 2 \after \duration $A \fine` causes the unfolded music to be missing the AA part.  I’ve noticed a tricky interplay between `\after` and `\volta x` previously.

—Joel

\version "2.24.0"

duration =
#(define-scheme-function (x) (duration-or-music?)
   (if (ly:duration? x)
       x
       (make-duration-of-length (ly:music-length x))))

AABAify =
#(define-music-function
  (A B) (ly:music? ly:music?)
  #{
    \repeat segno 2 {
      \after \duration $A \volta 2 \fine
      <<
        \volta #'() {
          \repeat volta 2 $A
        }
        \unfolded {
          \volta 1 \repeat volta 2 $A
          \volta 2 $A
        }
      >>
      \volta 1 $B
    }
  #})

A = {
  \repeat unfold 8 { a'4 a' a' a' | }
  \section
}

B = { \repeat unfold 8 { b'2 b' | }
  \section
}

AABA = \AABAify \A \B

\score {
  \AABA
}

\score {
  \unfoldRepeats \AABA
}