Re: why chords with notes of different duration is not supported?

[Graham Percival]

On Wed, Jan 12, 2011 at 01:17:46PM +0100, David Kastrup wrote:
> Graham Percival <address@hidden> writes:
> 
> > Before moving to computer science, I was a cello teacher.  And I'm now
> > playing first violin in an orchestra doing, amongst other things,
> > Tchaik's Romeo and Juliet.  I also played viola for half of my music
> > degree.  I'm very familiar with (bowed) string music.
> 
> So you should be perfectly aware that the notation Reinhold refers to
> (including references, by the way) exists.

Yes, and I (apparently falsely) believed that I showed how to
create that notation without using lilypond chord constructs.

> > There's a couple of separate issues here:
> > - what is the precise definition of a "chord" according to an
> >   arbitrary violinist?
> > - what is the precise definition of a "chord" according to an
> >   expert in music notation?
> > - what is the precise definition of a "chord" according to the
> >   lilypond manual?
> > - what is the precise definition of a "chord" according to the
> >   lilypond internal code (be it scheme or C++)?
> 
> I think you are focusing on the wrong issues here.  Precise definitions
> of "chord" don't even matter.  Lilypond is not a composer, it is
> notation software.  The purpose of notation software is to put down a
> suitable visible representation of how composers wish to see their
> concepts expressed when specified in a reasonable manner in Lilypond's
> input language.

I'm not focusing on them; I'm listing them so that people can
clearly state which one they're interested in.

> String music composers use chords with notes of different length.  There
> are references for that.  The execution is clear.  Whether or not you
> like the notation or concept, it is there to stay, and saying Lilypond
> should not be allowed to deal with this notation well because composers
> should rather get a clue is putting the cart before the horse.

So you are stating that:
1. violinists believe that a "chord" can contain notes of
different durations.
2. notation experts believe that a "chord" can contain notes of
different durations.
3. lilypond should have a way of creating this notation.

(note that I'm not using the word "believe" in a derogatory sense)

Point 1 is definitely correct.  I have no opinion on point 2; I am
neither an expert on notation, nor particularly interested in the
subject.  But I have no interest in disputing point 2.

The remaining question is "how should lilypond create that
notation", which can be divided into:
- "how should lilypond represent this notation internally" (I note
  that your patch uses simultaneous music rather than lilypond
  "chords")
- "how should we explain how to use this notation in our docs"

I have no opinion on the first question, since it's outside of my
expertise.  I do not expect the second question to be problematic,
but I will certainly review any doc patches, and if anything major
needs to be done, I'll definitely help with that.

> > Look, if you want to get a violinist "chord", you do this:
> > \new Staff \relative c'' {
> >   <<
> >     { \voiceOne g,4 }
> >     { \voiceOne d'4 }
> >     { \voiceOne b'4 }
> >     { \voiceOne g'2 }
> >   >>
> > }
> >
> > not hard.  Wrap it up in a music function to make it easier.
> 
> It works by accident, with clashing notehead warnings, and with stems
> that just happen to overlap if you are lucky and are not subject to
> Lilypond's usual operations ensuring good quality.

Oh, I didn't realize that the stems were overlapping rather than
actually merged.

> I resend my patch that will do the right thing when just writing
> 
> << g,4 d'4 b'4 g'2 >>

Great!

> I sent it to the devel list.  All I got was one comment that this would
> likely not be accepted.  Questions why this was so were not replied to.

...
Please tell me that you are not surprised that our development
process is a mess.  Please tell me that you know that we've been
making a lot of noise about this over the past six months.  Please
tell me that you are aware of the huge number of issues in:
http://lilypond.org/doc/v2.13/Documentation/contributor/policy-decisions
in particular, the "patch reviewing" item.  I've stated a few
times that this should be our first big policy discussion once
2.14 is out.

-snip-
> That's a deficiency, not an advantage of Lilypond.

Agreed!  And it's great to see some work in this area.

Cheers,
- Graham