rall. and accel stopped working in articulate. (issue 5927044)

[botialoach]

Reviewers: james <pkx166h_gmail.com>, thomas morley  
<thomasmorley65_googlemail.com>,

Message:
Hi folks,
  Thomas Morley noticed that rall. had stopped causing tempo change in
MIDI output when using articulate.

The patch I uploaded to Rietveld fixes that.

Description:
rall. and accel stopped working in articulate.

According to the the git logs, in February 2011 the way that tempo
changes for MIDI were interpreted changed from just the
tempoWholesPerMinute property to use a TempoChangeEvent.

This broke rall. in articulated MIDI output.

This patch brings the articulate script up-to-date wrt to the way that
tempo changes are signalled, and also adds accel. and poco accel. to
the list of accepted scripts.

Reported-by: Thomas Morley <address@hidden>
Signed-off-by: Peter Chubb <address@hidden>

Please review this at http://codereview.appspot.com/5927044/

Affected files:
  M ly/articulate.ly


Index: ly/articulate.ly
diff --git a/ly/articulate.ly b/ly/articulate.ly
index  
59424e515216b95776e038dadf653566ab25b3cb..4702e2030897ea1c972e6ece95d039b4b92b9cfb  
100644
--- a/ly/articulate.ly
+++ b/ly/articulate.ly
@@ -341,8 +341,18 @@
 ;     (ac:accel trillMusic factor))
  )))

-
-
+%
+% Generate a tempoChangeEvent and its associated property setting.
+%
+#(define (ac:tempoChange tempo)
+  (make-sequential-music
+   (list (make-music 'TempoChangeEvent
+         'metronome-count
+         tempo
+         'tempo-unit
+         (ly:make-duration 0 0 1 1))
+    (context-spec-music
+    (make-property-set 'tempoWholesPerMinute  tempo) 'Score))))

 % If there's an articulation, use it.
 % If in a slur, use (1 . 1) instead.
@@ -414,6 +424,14 @@
             (string= t "rall."))
            (loop factor (cons e newelements) tail (cons 'rall actions)))
           ((or
+            (string= t "accelerando")
+            (string= t "accel")
+            (string= t "accel."))
+           (loop factor (cons e newelements) tail (cons 'accel actions)))
+          ((or
+            (string= t "poco accel."))
+           (loop factor (cons e newelements) tail (cons 'pocoAccel actions)))
+          ((or
             (string= t "poco rall.")
             (string= t "poco rit."))
            (loop factor (cons e newelements) tail (cons 'pocoRall actions)))
@@ -477,25 +495,37 @@
 	     (make-music 'RestEvent 'duration (ly:make-duration len dots newnum  
newdenom))))))
          music)))

+       ((accel)
+       (set! ac:lastTempo ac:currentTempo)
+       (set! ac:currentTempo (ly:moment-div ac:currentTempo ac:rallFactor))
+       (let ((pset (ac:tempoChange ac:currentTempo)))
+        (if (null? (cdr actions))
+         (make-sequential-music (list pset music))
+         (make-sequential-music
+          (list pset (loop (cdr actions)))))))
+
+       ((pocoAccel)
+       (set! ac:lastTempo ac:currentTempo)
+       (set! ac:currentTempo (ly:moment-div ac:currentTempo ac:pocoRallFactor))
+       (let ((pset (ac:tempoChange ac:currentTempo)))
+        (if (null? (cdr actions))
+         (make-sequential-music (list pset music))
+         (make-sequential-music
+          (list pset (loop (cdr actions)))))))
+
        ((rall)
+       (set! ac:lastTempo ac:currentTempo)
        (set! ac:currentTempo (ly:moment-mul ac:currentTempo ac:rallFactor))
-       (let ((pset (make-music 'PropertySet
-          'value
-          ac:currentTempo
-          'symbol
-          'tempoWholesPerMinute)))
+       (let ((pset (ac:tempoChange ac:currentTempo)))
         (if (null? (cdr actions))
          (make-sequential-music (list pset music))
          (make-sequential-music
           (list pset (loop (cdr actions)))))))

        ((pocoRall)
+       (set! ac:lastTempo ac:currentTempo)
        (set! ac:currentTempo (ly:moment-mul ac:currentTempo ac:pocoRallFactor))
-       (let ((pset (make-music 'PropertySet
-          'value
-          ac:currentTempo
-          'symbol
-          'tempoWholesPerMinute)))
+       (let ((pset (ac:tempoChange ac:currentTempo)))
         (if (null? (cdr actions))
          (make-sequential-music (list pset music))
          (make-sequential-music
@@ -503,11 +533,8 @@

        ((aTempo)
        (set! ac:currentTempo ac:lastTempo)
-       (let ((pset (make-music 'PropertySet
-          'value
-          ac:currentTempo
-          'symbol
-          'tempoWholesPerMinute)))
+       
+       (let ((pset (ac:tempoChange ac:currentTempo)))
         (if (null? (cdr actions))
          (make-sequential-music (list pset music))
          (make-sequential-music
@@ -621,12 +648,12 @@
      (ac:adjust-props (ly:music-property music 'symbol) music)
      music)

-    (else  music))
+    (else music))
  ))



-% At last ... here's the music function that aplies all the above to a
+% At last ... here's the music function that applies all the above to a
 % score.
 articulate = #(define-music-function (parser location music)
               (ly:music?)