Re: Contemporary music required feature #1: chromatic transposition

[Hans Aberg]

On 22 Sep 2009, at 11:49, Joseph Wakeling wrote:

> > The correct accidental is a # plus a !/4. It then does not change the
> > scale degree. This will also be correct in if the sharp and  
> > microtonal
> > accents are relative a tuning system other than E12.
>
> No, it's a DOUBLE-sharp plus a 1/4, ...

Yes, sorry for the typo.

> ...which quite obviously does not exist.

I think LilyPond, once it has found the correct scale degree, computes  
the interval offset. As there is none for this particular offset, it  
typesets nothing. It should report at least a warning, though. The  
value stored inside should though be correct.

So I think you need to add a choice of glyph. LilyPond is too  
primitive to treat # and b and other accidentals as operators acting  
on all intervals.

> > In this case, staff position only changes if enharmonic equivalents  
> > are
> > applied. This is how it should be.
>
> That's why I stress I want this as an _option_ for transposition, not
> default functionality.

I think one needs to think through carefully how one wants to  
enharmonic equivalences be applied. It may vary with context. On most  
instruments, it can be used to simplify key signatures. On a harp, it  
may have to be applied note-by-note, as double sharps and flats are  
not available. If the tuning is other than E12, it implies a small  
slip in pitch.

  Hans