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;;;; This file is part of LilyPond, the GNU music typesetter.
;;;;
;;;; Copyright (C) 2000--2020 Han-Wen Nienhuys <[email protected]>
;;;; Jan Nieuwenhuizen <[email protected]>
;;;;
;;;; LilyPond is free software: you can redistribute it and/or modify
;;;; it under the terms of the GNU General Public License as published by
;;;; the Free Software Foundation, either version 3 of the License, or
;;;; (at your option) any later version.
;;;;
;;;; LilyPond is distributed in the hope that it will be useful,
;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;;; GNU General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU General Public License
;;;; along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; autochange.scm - fairly related to part combining.
(define-public (make-autochange-music music . ref-pitch)
(define ref-pitch-steps
(if (and (pair? ref-pitch) (car ref-pitch))
(ly:pitch-steps (car ref-pitch))
0))
(define (generate-split-list change-moment prev-dir event-list acc)
(if (null? event-list)
acc
(let* ((now-tun (caar event-list))
(evs (map car (cdar event-list)))
(now (car now-tun))
(notes (filter (lambda (x)
(ly:in-event-class? x 'note-event))
evs))
(pitch (if (pair? notes)
(ly:event-property (car notes) 'pitch)
#f))
(dir (if pitch
(sign
(- (ly:pitch-steps pitch) ref-pitch-steps))
0)))
;; tail recursive.
(if (and (not (= dir 0))
(not (= dir prev-dir)))
(generate-split-list #f
dir
(cdr event-list)
(cons (cons
(if change-moment
change-moment
now)
(if (< dir 0) 'down 'up)) acc))
(generate-split-list
(if pitch #f (if change-moment change-moment now))
dir
(cdr event-list) acc)))))
(let* ((m (make-music 'AutoChangeMusic))
(m1 (context-spec-music (make-non-relative-music music) 'Voice ""))
(context-list
(recording-group-emulate m1
(ly:parser-lookup 'partCombineListener)))
(rev (reverse! (cdar context-list)))
(split (reverse! (generate-split-list
#f
0
rev
'())
'())))
(set! (ly:music-property m 'element) m1)
(set! (ly:music-property m 'context-change-list) split)
m))
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