> On 13 Dec 2019, at 02:53, Freeman Gilmore <address@hidden> wrote:
>
>> On Thu, Dec 12, 2019 at 7:13 PM Andrew Bernard <address@hidden> wrote:
>> Hi Freeman,
>>
>> I still don't understand your aim here. Are you just trying to
>> understand the lilypond code or do you have some specific purpose or
>> application? It would help to know.
>>
>> Andrew
>
> Someday I may write a markup up for some accidentals. This may help me understand what I am doing with markup. For how I just want to know a little about how lexer reads the pitch, the octave. accidental and note size; and I may not be able to do that any way. I know nothing about flex and just learned it existed today. Also, I would like to see how the markup works around the accidental to place a string in it space. I read some of Separating input language and formatter in GNU Lilypond, and found it interesting. Looking for more details.
>
> I do not need to know all this to learn how to write a markup; just like to understand a little about how it works around the accidental. But I do need to learn more about scheme and markups.
LilyPond lack a way to indicate intervals,
I am aware of this part:
and accidentals are merely intervals of relative scale degree zero. A 5th has a relative scale degres 4, changes the position on the staff 4 steps, and similar for other intervals. The accidentals do not change the position on the staff.
In addition to ly:make-pitch, you might have ly:make-interval. Then one should be able to add and subtract intervals, add then to pitches, and the difference two pitches is an interval.
I would have to write the function, ly:make-interval. That would work for the common intervals, 2:3 and 4:5, in ET: but when you get up it the higher harmonic ratio intervals, different people define the intervals differently. It can be referenced to ET or Pythagorean and the number or what notes used in your system. For a simple example 4:7, (969¢) meantone is an Aug 6th in ET it is min 7th. The ratio 8:11, (551¢) can go either way based on you reference.
Thank you,
ƒg
LilyPond already has the internals for that, I would think, but lacks a suitable API and input syntax.