unfold-repeats

[Rune Zedeler]

I have done a scheme function that unfolds all repeats - but it is ugly.
The problem is that I do not know a clean way to find the c-functions
corresponding the properties "length" and "iterator-ctor".
The attached example is much uglier than it needed to be without knowing
how to access the functions (not necessary to pollute global name space)
- but I found it silly to do anything as long as I cannot find the c
functions cleanly.


#(define unfold-length '() )
#(define unfold-iterator-ctor '() )

#(define (init-unfold-repeats unfolded-repeat)
  (begin
    (set! unfold-length
          (ly-get-mus-property unfolded-repeat 'length))
    (set! unfold-iterator-ctor
          (ly-get-mus-property unfolded-repeat 'iterator-ctor))
    unfolded-repeat)
 )

#(define (unfold-repeats music)
  (let* ((es (ly-get-mus-property music 'elements))
         (e (ly-get-mus-property music 'element))
         (body (ly-get-mus-property music 'body))
         (alts (ly-get-mus-property music 'alternatives))
         (n  (ly-music-name music)))

    (if (equal? n "Repeated_music")
        (begin
          (ly-set-mus-property
           music 'length unfold-length)
          (ly-set-mus-property
           music 'iterator-ctor unfold-iterator-ctor)))
                  
    (if (pair? es)
        (ly-set-mus-property
         music 'elements
         (map unfold-repeats es)))

    (if (music? alts)
        (ly-set-mus-property
         music 'alternatives
         (unfold-repeats alts)))

    (if (music? body)
        (ly-set-mus-property
         music 'body
         (unfold-repeats body)))

    (if (music? e)
        (ly-set-mus-property
         music 'element
         (unfold-repeats e)))


    music))


mel = \notes \context Staff {
  \repeat tremolo 8 {c'32 e' }
  \repeat percent 2 { c''8 d'' }
  \repeat volta 2 {c'4 d' e' f'} 
  \alternative {
    { g' a' a' g' }
    {f' e' d' c' }
  }
  \bar "|."
}

\score { \notes {
  \apply #init-unfold-repeats \repeat unfold 2 {}

  \mel \break
  \apply #unfold-repeats \mel
 }
}




-Rune