custom line breaks more robust refs #21

verses_with_chords.ly

@@ -114,7 +114,16 @@
           (make-custom-linebreaks
             (cdr break-words)
             (ly:regex-replace
-              (ly:make-regex (string-append "(" (ly:regex-replace (ly:make-regex "(.)") (car break-words) "(?: *,[^,)]+\\)" 1 "|\\(?" 1 ")") "(?: *,[^,)]+\\))?)(.*)$"))
+              (ly:make-regex
+                (string-append
+                  "("
+                  (string-concatenate
+                    (map
+                      (lambda (character)
+                        (let ((escaped_char (ly:regex-quote (string character))))
+                             (string-append "(?: *,[^,)]+\\)" escaped_char "|\\(?" escaped_char ")")))
+                      (string->list (car break-words))))
+                  "(?: *,[^,)]+\\))?)(.*)$"))
               newtext
               1 "\n" 2))))))