Re: Detect slurred notes in callback function

[Jakub Pavlík]

Hi David,

as promised, here is my unsuccessful attempt based on a closure preserving state information between invocations.

Regards,

Jakub

---

\version "2.19.32"

#(define (contains-slur-event-with-direction? lst direction)

   (if (null-list? lst)

       #f

       (if (music-is-of-type? (car lst) 'slur-event)

             (eq? (ly:music-property (car lst) 'span-direction) direction)

             (contains-slur-event-with-direction? (cdr lst) direction))))

#(define (notehead-articulations notehead)

   (let ((noteevent (ly:event-property (event-cause notehead) 'music-cause)))

    (ly:music-property noteevent 'articulations)))

#(define (slur-opener? notehead)

   (contains-slur-event-with-direction? (notehead-articulations notehead) 1))

#(define (slur-closer? notehead)

   (contains-slur-event-with-direction? (notehead-articulations notehead) -1))

#(define (make-in-slur-callback inSlur notInSlur)

   (let ((slursOpen 0))

     (display "+++ Factory executed")

     ; this closure will be executed for each NoteHead

     (lambda (grob)

       (begin

        (display "+++ Closure executed")

        ; to see the order of NoteHead the callback is called for

        (display-scheme-music (ly:event-property (event-cause grob) 'origin))

         (cond

          ((slur-opener? grob) (set! slursOpen (+ slursOpen 1)))

          ((slur-closer? grob) (set! slursOpen (- slursOpen 1))))

         (if (> slursOpen 0)

             (inSlur grob)

             (notInSlur grob)))

           )))

\score {

  \relative c' {

    \override NoteHead #'color = #(make-in-slur-callback

      (lambda (grob) red)

      (lambda (grob) black))

    d e( f) g( a b c)

  }

}