Re: bar lines and unfolded repeats

[Dan Eble]

Dan Eble <dan <at> faithful.be> writes:

> 
> David Pounder <pounderd <at> lineone.net> writes:
> 
> > 
> > I would probably try using \tag round the \bar commands and
> > \removeWithTag for the volta-repeated section.
> > 
> 
> Well, it gets the job done (thanks for that), but it's less elegant
> than I was hoping for.  For one thing, I don't want to have to remove
> those bars in the usual case.  Is there a way to tag something so that
> it is *not* present by default, but only when requested?

I found a way that makes the ly a little cleaner.

acceptWithTag =
#(define-music-function
   (parser location tag music) (symbol? ly:music?)
   (music-map
    (lambda (m)
      (let* ((tags (ly:music-property m 'tags))
             (res (memq tag tags)))
        (if res
            (let ((void-music (ly:music-property m 'void)))
              (if (ly:music? void-music)
                  void-music
                  m)
              )
            m)))
    music))

void =
#(define-music-function (parser location music) (ly:music?)
   (make-music 'SequentialMusic 'void music))

sampleNotes = \relative c'
{
 
   \partial 2
   e e | c c c c | e2 \tag #'unfolded \void \bar "||"
   \repeat volta 2 { e4 e | e e e e | }
   \alternative {
     { d2 \tag #'unfolded \void \bar "" }
     { c2 \bar "|." }
   }
}

\book
{
  \score { \unfoldRepeats \acceptWithTag #'unfolded \sampleNotes }
  \score { \sampleNotes }
}