Issue 1321 in lilypond: Enhancement: add partcombineUp and partcombineDown functions

[lilypond]

Status: Accepted
Owner: ----
Labels: Type-Enhancement Priority-Low partcombine

New issue 1321 by v.villenave: Enhancement: add partcombineUp and  
partcombineDown functions
http://code.google.com/p/lilypond/issues/detail?id=1321

This feature request was posted by Mark on -devel a while back:
http://lists.gnu.org/archive/html/lilypond-devel/2010-03/msg00089.html

"""
While answering a question on -user, I found what looks like
an easily-solvable (?) limitation with /partcombine.  The
part-combiner.scm file is a little beyond me, but am I right
in thinking that /partcombine uses the equivalent of
/voiceOne and /voiceTwo when redistributing the notes?

If that's true, then the proposed functions would use:

partcombineUp   (voiceOne + voiceThree)
partcombineDown (voiceTwo + voiceFour)

This would allow combinations of 3 or even 4 voices to share
a common staff while taking advantage of the partcombine
functionality.  Would this be a trivial extension or is it
more complicated than that?
"