Re: Issue 1278: Arrow notation for quarter-tones. (issue3789044)

[k-ohara5a5a]

I advise against changing the internal representation of pitches.

I say that even though this looks like very good and careful code, and
after spending two hours studying it.  The extra complication, for which
the care was given, makes the system more difficult to learn,
understand, use, and repair.

Maybe convert the patch to distinguish quarter-tones using the existing
Rational alterations:
  sharp-down = 1/2 - 1/5 = 3/10
  natural-up =    +1/5   = 2/10
These sort in the same order as the solution in this patch.  It should
be fine if the internal representation is not exactly 1/4; some people
use the up-arrow to indicate pitches in just-intonation schemes.  Also,
for most instruments 'ces' is not really 1/2 a tone above 'c' but there
no harm from representing the sharp as 1/2.

The email chain linked in the patch mentions a similar method, saying
the 'problem' was that method was that transposing from the key of C to
the key of C-natural-up fails to convert a natural-up to a sharp.
However we do not ask Lilypond to convert 'fisis' to 'g' in a\transpose.
 Also, the proposed representation in this patch has the same 'problem'.


Transposition with automatic conversion (of 2/10 + 2/10 to 1/2, for
example) should be done by a function distinct form the current
\transpose, possibly written in Scheme using Mike Ellis' modal
transposition as a model.

http://codereview.appspot.com/3789044/