-We see the extra lyrics do not align properly with the notes. The
-word @notation{shine} should be sung on two notes, not one. This
-is called a @notation{melisma}, a single syllable sung to more
-than one note. There are several ways to spread a syllable over
-multiple notes, the simplest being to add a slur across them, for
-details, see @ref{Ties and slurs}:
+If you compile the code in the example above, you should see some
+warnings in the console output:
+
+@example
+song.ly:12:29: warning: barcheck failed at: 5/8
+ The | moon doth shine as
+ | bright as day; |
+song.ly:12:46: warning: barcheck failed at: 3/8
+ The | moon doth shine as | bright as day;
+ |
+@end example
+
+This is a good example of the usefulness of bar checks. Now,
+looking at the music, we see that the extra lyrics do not align
+properly with the notes. The word @notation{shine} should be sung
+on two notes, not one. This is called a @notation{melisma}, a
+single syllable sung to more than one note. There are several
+ways to spread a syllable over multiple notes, the simplest being
+to add a slur across them, for details, see @ref{Ties and slurs}: