Senza ripetizioni (without repeats)

If you want to reuse your music snippet without volta repeats (as mostly done at »Da Capo« or »Dal Segno«, sometimes explicitly written like »Da capo senza ripetizioni«), here is a music function \senzaRipet which extracts such a sequential music.

\version "2.24.0"

%% http://lsr.di.unimi.it/LSR/Item?id=866

%by: ArnoldTheresius

#(define-public (volta-repeats-only-once music)
  "This function replaces all 'percent volta' with 'sequential music', discarding all but the last alternative."
  (let*
   ((es (ly:music-property music 'elements))
    (e  (ly:music-property music 'element)))
   (if (memq 'repeated-music (ly:music-property music 'types))
    (let*
     ((props (ly:music-mutable-properties music))
      (old-name (ly:music-property music 'name)))
     (if (equal? old-name 'VoltaRepeatedMusic)
      (let*
       ((newprops (alist-copy props))
        (newprops (assoc-remove! newprops 'repeat-count))
        (last-of-elements (last-pair es))
        (newprops (assoc-set! newprops 'elements '()))
        (newprops (assoc-set! newprops 'element '()))
        (flattened  (flatten-alist newprops)))
       (set! es (cons e (if (pair? last-of-elements) last-of-elements '())))
       (set! e '())
       (set! music (apply make-music (cons 'SequentialMusic flattened)))))))
   (if (pair? es)
    (set! (ly:music-property music 'elements) (map volta-repeats-only-once es)))
   (if (ly:music? e)
    (set! (ly:music-property music 'element) (volta-repeats-only-once e)))
   music))

senzaRipet =
#(define-music-function (music) (ly:music?)
 (volta-repeats-only-once music))

\paper { tagline = ##f }

M = {
  c'1 \tag #'a \repeat volta 2 { d' }
  \repeat volta 3 { e'1 }
  \alternative { { f'1 } { g' } { a' } }
}

\markup { \null \translate #'( 1 . -3 ) \null } % 2.14.2 LSR problem workaroud

\score {
  \new Staff { \M }
  \header {
    piece = "\\Music ="
  }
}

\score {
  \new Staff { \senzaRipet { \M } }
  \header {
    piece = "\\senzaRipet { \\Music } ="
  }
}