Re: abc2ly and dance music (was: autobeam adjustment)

[Erik Sandberg]

On Sunday 20 February 2005 15.11, Laura Conrad wrote:
> >>>>> "ES" == Erik Sandberg <address@hidden> writes:
>
>     ES> abc2ly seems to use a weird method of dividing the music into
>     ES> bars. Remove the \set Score.defaultBarType = "empty", and
>     ES> insert a \partial 8 in the beginning of the piece, and it will
>     ES> work fine.
>
> I had actually figured out about the "\partial" issue.   But if you
> don't set the default bars to "empty", you remove the ability to use
> ABC with unevenly barred (or unbarred) music.

OK, you don't need to disable that. However, you need to set bar lengths of 
each bar

> There are a number of issues with translating ABC to lilypond.
> Writers of ABC expect to specify the barring and beaming, and
> sometimes the linebreaking. Lilypond expects to do these
> automatically.  When I was first using lilypond, my major use was for
> production of unbarred renaissance music, and so I modified abc2ly to
> respect the barring (or lack thereof) in the ABC source.  The
> Renaissance sources I was using didn't do beaming, so I wasn't at the
> time interested in preserving the ABC beaming, and as an ABC writer I
> had always used the option of letting the ABC printing program figure
> out the linebreaks.
>
> This state of abc2ly 2.0 is being problematic with my current project,
> which is producing some large type printouts of dance music.
>
>     ES> (Also, you might want to change all the \bar "|" commands to
>     ES> barchecks, |)
>
> I was going to sugest that abc2ly should put in a barcheck in addition
> to the \bar "|", which would eliminate the oddities in line breaking
> and beaming after the repeat sign.  But it seems to me that this is a
> misfeature in lilypond -- the barring seems to be reset by a repeat
> sign but *not* by a regular bar, whereas in all the music I know
> anything about it's the other way around -- repeat signs don't
> necessarily happen at rhythmic unit boundaries, but regular "|" bars
> usually do.

The timing of a bar is neither modified by "|" bars or by repeat bars. 
However, barchecks (|, as opposed to \bar "|") will generate warnings and 
re-align the music in case they aren't placed at the very end of a bar.

> The attached file shows a possible  ABC that will give lily enough
> information that she won't confuse a dance musician with her beaming
> and linebreaking.  This will be a little less necessary if abc2ly
> takes to respecting the ABC writers' beaming, but some form of it is
> still necessary if you don't want line breaks at wierd places.

I think the problem really is that Lilypond doesn't handle irregularly metered 
music very well; there is no user-friendly mechanism for handling music with 
irregular bar length. With current lilypond, the proper trick would be to let 
abc2ly set measureLength individually for each bar whose meter differs from 
the time signature.

See also the thread at 
http://lists.gnu.org/archive/html/bug-lilypond/2005-01/msg00076.html

Erik