Re: Odd output

[Keith OHara]

Phil Holmes <mail <at> philholmes.net> writes:
> 
> From: "Marco Correia" <marco.v.correia <at> gmail.com>
> >
> > \include "english.ly"
> > {
> > \clef treble
> > \time 4/4
> > <<
> > { fs'4 }
> > \\
> > { f'4 } >>
> >>>
>
> This was one of the first issues I raised, in June this year.  I think it 
> was my first bug report:
> 
> http://code.google.com/p/lilypond/issues/detail?id=1134
> 

 Lilypond's _only_ failure here is missing that the both notes need 
accidentals, because she compares only with previous notes, not simultaneous 
notes. (She does compare all voices.) If we force an explicit accidental with 
'!' 
  << { fis'4 } \\ {f'!4} >>
then Lilypond prints both a sharp and a natural -- with the natural always 
closer to the notehead so it is distinct from an extra natural that just 
cancels an earlier accidental.  

  Marco, and Phil, is sharp-natural-notehead the desired notation for this 
situation?  (I prefer it to the double-stem method, which I have seen only in 
Gardner Read's textbook, the "Displaying complex chords" snippet, and nowhere 
else.)

  For your computer-generated music, you might want to generate a forcing '!' 
whenever two notes of the same pitch name are produced at the same musical 
moment.  You might also consider "set-accidental-style 'dodecaphonic" and/or 
extraNatura=#f (see the manual for details). 

  Since you asked about Scheme, the decision on what accidentals are required 
is done by 'check-pitch-against-signature' in the file ../usr/share/lilypond/
current/scm/music-functions.scm which is installed with LilyPond.