(location (if (ly:input-location? input) (ly:input-file-line-char-column input) '()))
(x-ext (ly:grob-extent grob system-grob X))
(location (if (ly:input-location? input) (ly:input-file-line-char-column input) '()))
(x-ext (ly:grob-extent grob system-grob X))