underline for LyricText

private_includes/base/basic_format_and_style_settings.ily

@@ -306,3 +306,17 @@ rufWithMarkup =
 ruf =
 #(define-music-function (text) (string?)
    (rufWithMarkup (make-ruf-style-markup text)))
+
+underlineOn =
+#(define-music-function () ()
+   #{
+     \override LyricText.stencil =
+     #(lambda (grob)
+        (grob-interpret-markup grob (make-underline-markup (ly:grob-property grob 'text))))
+   #})
+
+underlineOff =
+#(define-music-function () ()
+   #{
+     \revert LyricText.stencil
+   #})