Re: Beaming eighth notes in threes in 3/4 time

[Carl Sorensen]

On 2/20/11 4:35 AM, "Phil Holmes" <address@hidden> wrote:

> ----- Original Message -----
> From: "Nick Payne" <address@hidden>
> To: <address@hidden>
> Sent: Sunday, February 20, 2011 3:37 AM
> Subject: Beaming eighth notes in threes in 3/4 time
> 
> 
>> Shouldn't this example have the notes in the second bar beamed three
>> together and three together? What I'm getting is three, then one, then
>> two:
>> 
>> \version "2.13.50"
>> 
>> \relative c' {
>>     \time 3/4
>>     c8 c c c c c
>>     \set beamExceptions = #'((end . (((1 . 8) . (3 3)))))
>>     c c c c c c
>> }

This is certainly a bug.  I'm not sure whether it's just a documentation bug
or whether it's a code bug.

3/4 has special beaming rules listed in the engraving handbooks that don't
fall under the regular beaming rules, so there's a hard-coded check.  I
don't remember the details right now, and I don't have time to look into it
(probably for a couple of weeks).  But it could be that the code is bad, or
it could just be that the code isn't explained properly in the docs.

IIRC, the engraving books said that 3/4 beamed in two should probably be 6/8
instead of 3/4.

> 
> \relative c' {
>      \time 3/4
>      c8 c c c c c
>      \set Timing.baseMoment = #(ly:make-moment 1 8)
>      \set Timing.beamExceptions = #'()
>      \set Timing.beatStructure = #'(3 3)
>      c c c c c c
>      \set Timing.beatStructure = #'(0 3 3)
>      c c c c c c
> }

This is also a bug.  One should never need to make a zero-length beat to
affect autobeaming behavior.  I don't know if it's the same bug or another
bug.

Phil's code is exactly what I would have written as the way to solve the
original request (except that I would have reversed the order of the
beamExceptions and beatStructure settings.  I don't know why it didn't work.
Again, it may be an issue of the special rule for beaming 3/4 time.

If nobody else does it in the meantime, I'll investigate when I get the
time.

In the meantime, let's make an issue.

Thanks,

Carl