Re: Rewrite chordnames - disentangle data from formatting (issue 223420043 by address@hidden)

[Carl Sorensen]

On 4/14/15 9:51 AM, "David Kastrup" <address@hidden> wrote:

>Carl Sorensen <address@hidden> writes:
>
>> On 4/13/15 6:06 PM, "Thomas Morley" <address@hidden> wrote:
>>
>>>Hi Carl,
>>>
>>>thanks for review.
>>>
>>>Pity to say my vacations ended :(
>>>I'll have much less time now, so work on this will be slowed down.
>>>I'll hope I can answer more thoroughly the upcoming days ...
>>
>> My summer time will be starting in a couple of weeks.  Maybe I can help
>> with this, now you've started it.
>
>I have to admit to not even having looked at the code yet.  But I still
>want to point out one real area of operation that would be nice to
>cover.
>
>Accordion standard bass...
>
>Basically, they lean towards being alternating chord accompaniment:
>
>\clef bass \time 3/4 c <c' e' g'> q | g q q | g <f' g' b'> q | d q q
>
>Namely, a pattern of alternating bass notes and chords, with the chord
>inversions determined by picking all the notes from a fixed octave.  The
>chord repertoire is x (major), x:m (minor), x:7^5 (major seventh missing
>the fifth) and x:dim7^5 (full diminuished missing the fifth), all of
>those picking an inversion in a single octave.  Chords get additionally
>_labelled_ in the score (accordion players are not too good at actually
>reading anything but the rhythm in bass clef) as x, xm, x7, and xv (the
>latter being the German naming; it may be xdim in other languages),
>while the bass notes are marked with uppercase letters.  There may be
>_combined_ chords by pressing more than one button: for example, a:m7
>can be represented as "c+am", and a:m6 can be represented as "am+av".
>
>So we have, basically, an inversion-ignoring chord pattern recognition
>problem, in a similar vein as guitar chord diagrams have a mostly
>inversion-ignoring chord pattern recognition problem.
>
>So it would be nice to have the chord recognition, the naming
>(upper/lowercase), particular pattern recognition/exceptions all sort of
>independent so that one may plug them together in different manners.


I think that this should be totally doable.  I envision that the chord
pattern alist will have an entry for inversion; the accordion chord name
print out routine can just ignore the inversion.

I think that Harm's current patch already carves out the naming part of
the chord (upper/lower case root, alterations) separately; ultimately I
think that will become part of the chord pattern alist.

Thanks for your input.  As we get further along, we'll see if the
structure works right.  The current patch is just a start at separating
the recognition from the markup.

Carl