support für römische Zahlen in den Strophen

basic_format_and_style_settings.ly

@@ -95,8 +95,16 @@ schwarzkopf =
    \override NoteHead.color = #grey
   #})
 
+romanStanza =
+  #(define-music-function (parser location) ()
+  #{ \override StanzaNumber.style = #'roman #})
+
 stanza =
-  #(define-music-function (parser location stanzanumber) (number?)
-  #{ \set stanza = #(ly:format stanzaFormat stanzanumber) #})
+#(define-music-function (parser location stanzanumber) (number?)
+  (make-apply-context
+    (lambda (context)
+      (let* ((stanzastyle (ly:assoc-get 'style (ly:context-grob-definition context 'StanzaNumber)))
+             (formattedStanzaNumber (format #f (if (eq? stanzastyle 'roman) romanStanzaFormat stanzaFormat) stanzanumber)))
+        (ly:context-set-property! context 'stanza formattedStanzaNumber)))))
 
 ref = { \set stanza = \refString }

default_style.ly

@@ -15,6 +15,7 @@ songTocColumns = 3
 globalSize = 15
 lyricSize = 1.6
 stanzaFormat = "~a."
+romanStanzaFormat = "~@r."
 refString = "Ref.:"
 % hübsche Wiederholungszeichen für den Liedtext
 repStart = "𝄆"