Fix a segfault caused by improper initialization of SCM.

[lilypond.git] / scm / song.scm

diff --git a/scm/song.scm b/scm/song.scm
index 88b4423702bb0037b33155f97257bdb0f1f14480..9dbca9fd6286d7c1c8204075840737c8e4d287fc 100644 (file)
--- a/scm/song.scm
+++ b/scm/song.scm
@@ -141,33 +141,28 @@
     (exact->inexact (* (expt 2 (- log)) (+ 1 (/ dots 2)) (/ (car factor) (cdr factor))))))
 
 (define (tempo->beats music)
-  (let* ((tempo-spec (or (find-child-named music 'MetronomeChangeEvent)
-                         (find-child-named music 'SequentialMusic)))
+  (let* ((tempo-spec (find-child-named music 'SequentialMusic))
          (tempo (cond
-                 ((not tempo-spec)
-                  #f)
-                 ((music-name? tempo-spec 'MetronomeChangeEvent)
-                  (* (ly:music-property tempo-spec 'metronome-count)
-                     (duration->number (ly:music-property tempo-spec 'tempo-unit))))
-                 ((music-name? tempo-spec 'SequentialMusic)
-                  (* (property-value
-                      (find-child tempo-spec (lambda (elt)
-                                              (let ((tempo (music-property? elt 'tempoUnitCount)))
-                                                (if (pair? tempo)
-                                                    (round (/ (+ (car tempo) (cdr tempo)) 2))
-                                                    tempo)))))
-                     (duration->number
-                      (property-value
-                       (find-child tempo-spec (lambda (elt) (music-property? elt 'tempoUnitDuration)))))))
-                 (else
-                  (format #t "Programming error (tempo->beats): ~a~%" tempo-spec)))))
+                (tempo-spec
+                 (let ((tempo-event (find-child-named tempo-spec
+                                                      'TempoChangeEvent)))
+                   (and tempo-event
+                        (let ((count (ly:music-property tempo-event
+                                                        'metronome-count)))
+                          (* (if (pair? count)
+                                 (round (/ (+ (car count) (cdr count)) 2))
+                                 count)
+                             (duration->number
+                              (ly:music-property tempo-event 'tempo-unit)))))))
+                (else
+                  (format #t "Programming error (tempo->beats): ~a~%"
+                         tempo-spec)))))
     (debug-enable 'backtrace)
-    (if (and tempo (music-name? tempo-spec 'SequentialMusic))
-        (set! *default-tempo* (property-value
-                               (find-child tempo-spec (lambda (elt) (music-property? elt 'tempoWholesPerMinute))))))
-    (if tempo
-        (round (* tempo (expt 2 (+ 2 *base-octave-shift*))))
-        #f)))
+    (and tempo
+        (set! *default-tempo* (property-value
+                               (find-child tempo-spec (lambda (elt)
+                                                        (music-property? elt 'tempoWholesPerMinute)))))
+        (round (* tempo (expt 2 (+ 2 *base-octave-shift*)))))))
 
 (defstruct music-context
   music