Transposing pitches with minimum accidentals (“smart” transpose): Difference between revisions

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VisualWikitext

@@ Line 12: / Line 12: @@
 #(define (naturalize-pitch p)
     (let ((o (ly:pitch-octave p))
+         ;; `ly:pitch-alteration` returns quarter tone steps.
           (a (* 4 (ly:pitch-alteration p)))
-         ;; alteration, a, in quarter tone steps,
-         ;; for historical reasons
           (n (ly:pitch-notename p)))
       (cond
-       ((and (> a 1) (or (eqv? n 6) (eqv? n 2)))
+       ((and (> a 1)
+            (or (eqv? n 6) (eqv? n 2)))
         (set! a (- a 2))
         (set! n (+ n 1)))
-       ((and (< a -1) (or (eqv? n 0) (eqv? n 3)))
+       ((and (< a -1)
+            (or (eqv? n 0) (eqv? n 3)))
         (set! a (+ a 2))
         (set! n (- n 1))))
       (cond
-       ((> a 2) (set! a (- a 4)) (set! n (+ n 1)))
+       ((> a 2)
-       ((< a -2) (set! a (+ a 4)) (set! n (- n 1))))
+       (set! a (- a 4))
-      (if (< n 0) (begin (set! o (- o 1)) (set! n (+ n 7))))
+       (set! n (+ n 1)))
-      (if (> n 6) (begin (set! o (+ o 1)) (set! n (- n 7))))
+       ((< a -2)
+       (set! a (+ a 4))
+       (set! n (- n 1))))
+      (when (< n 0)
+       (set! o (- o 1))
+       (set! n (+ n 7)))
+      (when (> n 6)
+       (set! o (+ o 1))
+       (set! n (- n 7)))
       (ly:make-pitch o n (/ a 4))))
@@ Line 34: / Line 43: @@
           (e (ly:music-property music 'element))
           (p (ly:music-property music 'pitch)))
-      (if (pair? es)
+      (when (pair? es)
-         (ly:music-set-property!
+       (ly:music-set-property! music 'elements
-          music 'elements
+                               (map naturalize es)))
-          (map naturalize es)))
+      (when (ly:music? e)
-      (if (ly:music? e)
+       (ly:music-set-property! music 'element
-         (ly:music-set-property!
+                               (naturalize e)))
-          music 'element
+      (when (ly:pitch? p)
-          (naturalize e)))
+       (set! p (naturalize-pitch p))
-      (if (ly:pitch? p)
+       (ly:music-set-property! music 'pitch p))
-         (begin
-           (set! p (naturalize-pitch p))
-           (ly:music-set-property! music 'pitch p)))
       music))
 naturalizeMusic =
-#(define-music-function (m)
+#(define-music-function (m) (ly:music?)
-   (ly:music?)
     (naturalize m))
 music = \relative c' { c4 d e g }
-\score {
+\new Staff {
-  \new Staff {
+  \transpose c ais { \music }
-    \transpose c ais { \music }
+  \naturalizeMusic \transpose c ais { \music }
-    \naturalizeMusic \transpose c ais { \music }
+  \transpose c deses { \music }
-    \transpose c deses { \music }
+  \naturalizeMusic \transpose c deses { \music }
-    \naturalizeMusic \transpose c deses { \music }
-  }
-  \layout { }
 }
 </lilypond>