Re: weird de-beaming behavior

[Urs Liska]

Am 20. Juni 2018 14:26:51 MESZ schrieb Phil Holmes <address@hidden>:
>Well,
>
>This example is almost identical to your first example.  A beamed note
>is broken by a bar and break and the beam is broken.  Lily doesn't know
>how to beam them.  The 2 leftover notes are beamed in both examples -
>again i don't know why, but it's quite consistent behaviour and
>consistent with lily not knowing what you intend until you tell her.
>
>You could keep making odd examples of undefined beaming until the cows
>come home, but surely it would be a lot quicker just to beam
>manually???

The problem is that this break is conditional, so it's not clear before whether 
there will be a break within the measure.

  \time 3/4
  c8 [ c c c c c ]

  Vs
  c8 [ c c c ] \bar "" \break c [ c ]

That looks like a prime case for the \choice command I'll be doing shortly.

Urs

PS: As to the *why* I have the vague recollection that beaming rules define 
where beams can be *ended*. This would explain why the beam before the break 
doesn't work but the one after does.

>
>--
>Phil Holmes
>
>
>  ----- Original Message ----- 
>  From: N. Andrew Walsh 
>  To: Phil Holmes 
>  Cc: lilypond-user 
>  Sent: Wednesday, June 20, 2018 12:30 PM
>  Subject: Re: weird de-beaming behavior
>
>
>  Hi Phil,
>
>On Wed, Jun 20, 2018 at 1:18 PM Phil Holmes <address@hidden>
>wrote:
>
>I'm no expert on lily's beaming system.  However, in your second
>example you don't break an existing beam with a bar/line break, so it's
>rather different from the first where the "correct" beaming was broken.
>
>
>Not knowing anything about how Lily works, I'm inclined to agree. in
>3/4 (at least here) a measure comprising only 8th-notes will be beamed
>straight through, thus (pseudo code):
>
>
>  e8[ e c' c c c c]
>
>
>  Whereas a 4/4 bar is beamed in two groups of four.
>
>
>So you're correct, that there's something going on with default beaming
>being broken up. In fact, with the following MWE (also in 4/4):
>
>
>  \version "2.19.80"
>
>
>  \relative c'' {
>
>
>  c e, g8 a 
>  \bar "" \break 
>  g e g16 a b8
>  }
>
>
>the "g8 a" at the end of the first line is *also* broken into two
>unbeamed 8th-notes, but the two that follow the break do not. Why would
>this be? 
>
>
>  Cheers,
>
>
>  A