Fix Issue 2380: formatting of lyrics, \versus and \respondum

diff --git a/ly/gregorian.ly b/ly/gregorian.ly
index af073aa42d0f3265cb1daa4dcf6e9e55414bb640..b268cb8e4851ec2aca884b522d935e638991bbe9 100644 (file)
--- a/ly/gregorian.ly
+++ b/ly/gregorian.ly
@@ -3,7 +3,7 @@
   $Id$
 %}
 
-\version "2.15.10"
+\version "2.15.30"
 
 %
 % Declare memorable shortcuts for special unicode characters
@@ -22,28 +22,18 @@ iij = \lyricmode { iij }
 % Given some music that represents lyrics, add a prefix to the first
 % lyric event.
 %
-% TODO: Robustify this function.  For example, this function works
-% correctly for "\versus { some lyrics }", but it barfs with a wrong type
-% argument error for e.g. "\versus some lyrics".
-%
 #(define (add-prefix-to-lyrics prefix music)
-   (make-music
-    'SequentialMusic
-    'elements (append
-              (cons
-               (let* ((elems (car (ly:music-property music 'elements)))
-                      (props (ly:music-mutable-properties elems))
-                      (events (filter (lambda (x)
-                                        (equal? (car x) 'elements))
-                                      props))
-                      (first-evt (cadar events))
-                      (first-syllable (ly:prob-property first-evt 'text))
-                      (first-duration (ly:prob-property first-evt 'duration)))
-                 (make-music
-                  'LyricEvent
-                  'duration first-duration
-                  'text (string-append prefix first-syllable)))
-               (cdr (ly:music-property music 'elements))))))
+   (let ((found? #f))
+     (map-some-music
+      (lambda (m)
+       (if found? m
+           (and (music-is-of-type? m 'lyric-event)
+                (begin
+                  (set! (ly:music-property m 'text)
+                        (string-append prefix (ly:music-property m 'text)))
+                  (set! found? #t)
+                  m))))
+      music)))
 
 % Add unicode 2123 (versicle) as prefix to lyrics.
 versus =