Flags cross-staff semi ties. (issue 8857043)

[n . puttock]

Hi Mike,

Generally LGTM, but since there's nothing in the code which requires C++
code I favour adding a callback to output-lib.scm:

(define-public (semi-tie::calc-cross-staff grob)
  (let* ((note-head (ly:grob-object grob 'note-head))
         (stem (ly:grob-object note-head 'stem)))
    (and (ly:grob? stem)
         (ly:grob-property stem 'cross-staff #f))))

BTW, this surprised me a bit while fiddling with the regression test:

<<
 \new Staff = "up" \relative c' {
 f8
 \change Staff = "down"
 c e\f %oops
 \change Staff = "up"
 f
 }
 \new Staff = "down" { \clef bass s2 }


Cheers,
Neil





https://codereview.appspot.com/8857043/