Quarter-tone notation with arrows

[Joseph Wakeling]

Hello all,

One of the delights to see in the News for 2.12 was the new material on
quarter-tone and other microtonal notation.  However, I have one problem...

The standard Lilypond quarter-tone notation uses pitches -is and -es
(sharp and flat), -ih and -eh (quarter-tone sharp and flat) and -isih
and -eseh (three-quarter sharp and flat).  This is fine with the
standard quarter-tone accidentals but arrow notation allows for more
flexibility: you can have -iseh (sharp, a quarter down) or esih (flat, a
quarter sharp), and these are not necessarily the same as -ih or -eh,
just as D-flat is not necessarily the same as C-sharp.

Anyway, from looking at the Makam example it's apparent how to define
arbitrary pitch names to associate with given microtonal alterations; it
would be easy to define -iseh and -esih.  What I don't understand is the
glyph definition, which appears to associate a given alteration uniquely
with a given accidental.

So, for example, a pitch alteration of -1/4 can apparently only be
associated with one accidental even though theoretically it could be
represented by _either_ a natural sign with a down-arrow or a flat sign
with an up-arrow.

The 'if' statements from makam.ly don't give any clue because as far as
I can tell they relate to a predefined static term (in this case, an
option as to whether the EKSIK-IKI AND -UC flats should have a slash).

I guess I could cheat by making e.g. -eh -24/100 and -esih -26/100,
which would give a working solution, but is there a way of getting what
I want (a full set of quarter-tone arrow accidentals) without such recourse?

Thanks & best wishes,

    -- Joe