2015-08-17 0:18 GMT+02:00 Simon Albrecht <address@hidden>:
Lily is being very honest and makes a kind warning telling us that she
doesn’t know how to parenthesize spanners. But it would be really nice if we
could teach her that :-)
%%%%%%%%%%%%%%%%%%%%%%%%%%
\relative { c''-\parenthesize \> c c c
c2\! -\parenthesize ~ c
}
%%%%%%%%%%%%%%%%%%%%%%%%%%
<https://code.google.com/p/lilypond/issues/detail?id=4565>
I once made the attached code.
It still compiles. You will observe several warnings, they are intended ;)
I never had the time and energy to finish it.
May be a good starting point, though