Re: PATCH: Arrowed accidentals for microtone notation

[Joseph Wakeling]

Graham Breed wrote:
> Oh, I didn't realize Google were covering this.  I've done some work
> with Lilypond and microtonality.  Somebody said I should add something
> to the snippets repository, but I've been lazy, so I haven't done
> that.  There are examples in this bundle:
> 
> http://x31eq.com/magic/tripod-code.zip

Thanks for that!  It will take time to digest (both the musical concepts
and the Lilypond implementation) but looks fascinating and beautiful.

> That can be done with a function to switch between different sets of
> accidentals.  So \preferNaturals and \preferSharps, for example.
> There may be ways of combining this with \once and \tweak as well.

I'd prefer not to do that for semantic reasons.  In my conception of
arrow-notated quarter-tones, C-quarter-sharp is enharmonically, but not
semantically, the same as C-sharp-quarter-flat (just as D# is
enharmonically but not semantically the same as Eb).

> If you insist on a certain spelling of quartertones, doesn't that
> become a crap shoot anyway when you combine it with transpositions?
> Like, if you have the quartertone below C, and you want it to be C
> sharp up rather than C down, and then you transpose it up a semitone,
> what would the correct spelling be?  How is the user supposed to
> specify the correct spelling for both cases?

My approach for all 'standard' transpositions would be 'transpose the
underlying notes chromatically and keep the arrows the same'.  So
C-flat-up (I think that's what you meant) would become C-up and C-down
would become C-sharp-down.  The question is how to implement that
successfully ... :-)

Quarter-tone transposition is more tricky but it's probably best to
start with standard transposition first.

> I believe there's  already a snippet for chromatic transposition.
> That's probably the place to start for some of these issues.
> Transposition certainly works for quartertones (and I've tested more
> "interesting" situations) but you will get sharp-and-a-halfs coming
> out.  But then normal transpositions might give you double sharps.  If
> you don't want that I don't think it's a new issue with microtonality.

OK, I will look into that and see if I can incorporate it into the
material I have already prepared.  If it works I will prepare a snippet
for LSR that can perhaps in the long run be combined with Maximilian's
proposed patch here.

Incidentally, does that mean that an option for chromatic transposition
is not a standard part of Lilypond?  It was a question I'd meant to ask
previously, though not in relation to the microtonal issue.

Best wishes,

    -- Joe