Re: Beaming, partcombine and pickups

[David Wright]

On Thu 15 Sep 2016 at 17:15:02 (-0600), David F. wrote:
> I have a song in 9/8 time with a pickup of three eighth notes.  I expect 
> Lilypond to beam those three eighth notes together, but it does not when I 
> combine two voices with partcombine.
> 
> Am I doing something wrong?  Is Lilypond doing something wrong?  How might I 
> work around this?

Well, it's only last week that you asked "Is there a way to combine
two voices and print both stems (up and down) when the voices share a
note?  \partcombine does not appear to do this by default."

So now you've demonstrated the danger of doing that: it interferes
with the beaming. Isn't the answer just to decide on your priorities?

\partcombine #'(0 . 9)   will combine the unison notes and allow the
flag to become a beam in the appropriate direction.
Manually beaming either of the parts (or both, of course) will do the
opposite: produce beams above and below.
Which do you want?

There's an additional danger in your second example of course. If the
pickup's pitches happened to be in the reverse order, and if you were
working in 6/8 (both entirely possible in another tune), you would
have generated the beaming for a 3/4 time signature rather than a 6/8
one. (Many hymnbooks lack time signatures.)

I'm not sure it's wise of me to ask what the attraction is of the
American convention of part-combining.

Cheers,
David.