Re: Function to add a drone staff?

[Paul Morris]

Gilles Sadowski wrote
> With the "manual" drone, one writes ties between
> the notes; is it possible to add it to the function?

Well, the first thing I tried was to just add a tie to every note like so:

dronify =
#(define-music-function (parser location drone melody)
   (ly:pitch? ly:music?)
   (music-map
    (lambda (m)
      (if (ly:pitch? (ly:music-property m 'pitch))
          (begin
           (ly:music-set-property! m 'pitch drone)
           (ly:music-set-property! m 'articulations
             (list (make-music (quote TieEvent))))))
      m)
    melody))

But that led to "warning: unterminated tie" any time there was a rest.  So I
came up with the following, which is not that elegant, but seems to get the
job done and without warnings.  No guarantees on how robust it is with
actual music.

HTH,
-Paul

%%%%%%%%%%%%%%%%%%%%%%%%%%

\version "2.18.2"

dronify =
#(define-music-function (parser location drone melody)
   (ly:pitch? ly:music?)
   (let* ((prev #{ #})
          (current #{ #})
          (art '())
          (drone-part
           (music-map
            (lambda (m)
              (set! prev current)

              (if (and (music-is-of-type? m 'note-event)
                       (ly:pitch? (ly:music-property m 'pitch)))
                  ;; change the pitch
                  (begin
                   (ly:music-set-property! m 'pitch drone)
                   (if (and (music-is-of-type? prev 'note-event)
                            (ly:pitch? (ly:music-property prev 'pitch)))
                       ;; add tie to previous note
                       ;; avoid overwriting existing articulations
                       (begin
                        (set! art (ly:music-property prev 'articulations))
                        (ly:music-set-property! prev 'articulations
                          (append art (list (make-music (quote
TieEvent)))))))))

              (set! current m)
              prev)
            melody)))
     #{ #drone-part #current #}))


#(define (octave-up m t)
   (let* ((octave (1- t))
          (new-note (ly:music-deep-copy m))
          (new-pitch (ly:make-pitch
                      octave
                      (ly:pitch-notename (ly:music-property m 'pitch))
                      (ly:pitch-alteration (ly:music-property m 'pitch)))))
     (set! (ly:music-property new-note 'pitch) new-pitch)
     new-note))

#(define (octavize-chord elements t)
   (cond ((null? elements) elements)
     ((eq? (ly:music-property (car elements) 'name) 'NoteEvent)
      (cons (car elements)
        (cons (octave-up (car elements) t)
          (octavize-chord (cdr elements) t))))
     (else (cons (car elements) (octavize-chord (cdr elements ) t)))))

#(define (octavize music t)
   (if (eq? (ly:music-property music 'name) 'EventChord)
       (ly:music-set-property! music 'elements (octavize-chord
                                                (ly:music-property music
'elements) t)))
   music)

makeOctaves = #(define-music-function (parser location arg mus) (integer?
ly:music?)
                 (music-map (lambda (x) (octavize x arg)) (event-chord-wrap!
mus)))

melody = \relative f' {
  c4 d c8( d8) r4
  g4\staccato a r b4
}

<<
  \melody
  \makeOctaves #1 \dronify g \melody
>>





--
View this message in context: 
http://lilypond.1069038.n5.nabble.com/Function-to-add-a-drone-staff-tp174261p174318.html
Sent from the User mailing list archive at Nabble.com.