Re: apc2ly

[Jan Nieuwenhuizen]

[redirected to lilypond-user; please keep this on a list.]

Peter Rosenbeck writes:

> I found that the converter does not preserve the grouping of the
> notes. Each group of three eighths should be joined, but this is
> only done in measures 1 and 10. I've enclosed the ly and abc files
> for your reference.

abc2ly does not produce beaming, it leaves that up to LilyPond, so it
seems.  Your piece has irregular meter, but that is not implemented in
abc2ly, so LilyPond does not know about it.

LilyPond needs to know about the meter to be able to produce the right
beaming.

You can see for yourself what goes wrong if you do not hide the actual
bar lines:

voicedefault = \notes {
%% do not hide bar lines
%% \property Score.defaultBarType="empty"

\time 3/8 \key g \major   \repeat volta 2 {   d''8    d''8    d''8    \bar ""  
 d''4    b'4    \bar ""   b'8    a'8    b'8    \bar ""   c''4    a'4    
\bar ""   a'8    a'8    b'8    \bar ""   c''8.    b'16    a'8    \bar ""   
a'8    b'8    c''8    \bar ""   d''4    b'4    \bar ""   d''8    d''8    d''8 
   \bar ""   d''4    b'4    \bar ""   b'8    a'8    b'8    \bar ""   c''4    
a'4    \bar ""   a'8    a'8    b'8    \bar ""   c''8.    b'16    a'8    
\bar ""   d''8    d''8    fis'8    \bar ""   g'4.    }   
}

\score{
        \notes <<

        \context Staff="default"
        {
            \voicedefault 
        }

    >>
        \paper {
        }
        \midi {}
}


What you probably want to try first, is making the right corrections
by hand, before looking at abc2ly.  You should experiment a bit with
the alternating meter, doing something like:


    voicedefault = \notes {
        %%    \property Score.defaultBarType="empty"

        \time 3/8 \key g \major \repeat volta 2 {
            d''8 d''8 d''8 
            \bar "|" d''4 b'4 
            \bar "|" b'8 a'8 b'8 
            \bar "|" c''4 a'4 
            \bar "|" a'8 a'8 b'8 
            \bar "|" c''8. b'16 a'8 
            \bar "|" a'8 b'8 c''8 
            \bar "|" d''4 b'4 
            \bar "|" d''8 d''8 d''8 
            \bar "|" d''4 b'4 
            \bar "|" b'8 a'8 b'8 
            \bar "|" c''4 a'4 
            \bar "|" a'8 a'8 b'8 
            \bar "|" c''8. b'16 a'8 
            \bar "|" d''8 d''8 fis'8 
            \bar "|" g'4.
        } 
    }

    \score {
        \context Staff <<
            %% Invisible alternating time signature

            \notes <<
                {  s4 \override Staff.TimeSignature #'print-function = #'() 
                   %%\property Staff.TimeSignature \set #'brew_molecule = #'()
               }
                {
                    \repeat unfold 2 { \time 3/8 s8*3 \time 1/2 s2 }
                    \time 3/8 s8*6
                    \repeat unfold 3 { \time 3/8 s8*3 \time 1/2 s2 }
                    \time 3/8 s8*6
                }
            >>
            \voicedefault
        >>
    }


> I'd like to contribute to the LilyPond project and maybe start working on
> improving the abc converter. I am a seasoned Smalltalker and Scheme
> programmer,

You're most welcome to join in!

> but LilyPond is quite new to me.  Also, for purely professional
> reasons, I prefer working on a Windows platform.

professional reasons... now you got me wondering ;-) Just joking, I
think we can do with a developer who likes to work with Windows.

> Maybe you could point me to an entry point in the documentation or
> on your site...

What are you looking for?  Just try http://lilypond.org and follow
`documentation'.  There's extensive user documentation, but alas,
developer documentation is a weak spot.  This is hopefully being
addressed by other new developers.

If you're looking to improve abc2ly, you can find it in the sources
at:

   ./scripts/abc2ly.py

It's a python script.  If you do not already know python, don't be
scared away.

Jan.

-- 
Jan Nieuwenhuizen <address@hidden> | GNU LilyPond - The music typesetter
http://www.xs4all.nl/~jantien       | http://www.lilypond.org