Code review/advice for accordion registers

[David Kastrup]

> I'm not topposting

after getting some advice here, I tried coding some accordion register
setting stuff.  I have little enough available input on the best
available options and names, no idea whatoever about Bayan
(consequently, no Bayan bass here), and have failed to work with
context-sensitive settings.  For example, I'd like to have something
like Voice.registerInstrument which I can independently set per Voice
and which is inherited into subvoices and can be used with \set,
\override etc.  No idea how to do this.

It also feels unclean to have to define this as macro, but short of
using macros, I have no idea how to feed the requisite material into
define-markup-command, itself a macro.  All of this looks pretty ugly.

This defines both music command and markup command (more important at a
later stage when the music command will simultaneously change the
midiRegisterInstrument of the Voice or something while the markup
command does just markup).

Ok, any advice how to wedge material into new Voice context properties?
How to do that?

% The default discant register set has been more or less modeled after
% numeric Swiss notation like depicted in
% <URL:http://de.wikipedia.org/wiki/Register_%28Akkordeon%29>,
% omitting the slashes and dropping leading zeros.
%
% The names are basically three-digit numbers with the lowest digit
% specifying the number of 16' reeds, the tens the number of 8' reeds,
% and the hundreds specifying the number of 4' reeds.  Without
% modification, the specified number of reeds in 8' is in the symbol.
% Newer instruments may have register choices between 8' with and
% without cassotto.  Notationally, the central dot then indicates use
% of cassotto.  You can suffix the tens' digits "1" and "2" with "+"
% or "-" to indicate clustering the dots at the right or left
% respectively rather than centered.
#(define defaultDiscant
  '((glyph . "accordion.accDiscant")
    (reedbank
     (L . ((dots . ((0 . 0.5)))))
     (M . ((dots . ((0 . 1.5)))))
     (MM . ((dots . ((1 . 1.5)))))
     (MMM . ((dots . ((-1 . 1.5)))))
     (H . ((dots . ((0 . 2.5))))))
    (register
     ("1" (reedbanks L))
     ("10" (reedbanks M))
     ("11" (reedbanks L M))
     ("1+0" (reedbanks MM))
     ("1+1" (reedbanks MM L))
     ("1-0" (reedbanks MMM))
     ("1-1" (reedbanks MMM L))
     ("20" (reedbanks MMM MM))
     ("21" (reedbanks MMM MM L))
     ("2+0" (reedbanks MM M))
     ("2+1" (reedbanks MM M L))
     ("2-0" (reedbanks MMM M))
     ("2-1" (reedbanks MMM M L))
     ("30" (reedbanks MMM MM M))
     ("31" (reedbanks MMM MM M L))
     ("100" (reedbanks H))
     ("11" (reedbanks H L))
     ("110" (reedbanks H M))
     ("111" (reedbanks H L M))
     ("11+0" (reedbanks H MM))
     ("11+1" (reedbanks H MM L))
     ("11-0" (reedbanks H MMM))
     ("11-1" (reedbanks H MMM L))
     ("120" (reedbanks H MMM MM))
     ("121" (reedbanks H MMM MM L))
     ("12+0" (reedbanks H MM M))
     ("12+1" (reedbanks H MM M L))
     ("12-0" (reedbanks H MMM M))
     ("12-1" (reedbanks H MMM M L))
     ("130" (reedbanks H MMM MM M))
     ("131" (reedbanks H MMM MM M L)))))

% The default Bass definitions have been modeled after the article
% <URL:http://www.accordions.com/index/art/stradella.shtml>
% originally appearing in Accord Magazine
#(define defaultStdBass
  '((glyph . "accordion.accStdbase")
    (register
     ("Soprano" (reedbanks Soprano))
     ("Alto" (reedbanks Alto Soprano))
     ("Tenor" (reedbanks Tenor Alto Soprano))
     ("Master" (reedbanks Bass Tenor Contralto Alto Soprano))
     ("Soft Bass" (reedbanks Bass Tenor Contralto))
     ("Soft Tenor" (reedbanks Tenor Alto))
     ("Bass/Alto" (reedbanks Bass Alto Soprano)))
    (reedbank
     (Soprano . ((dots . ((0 . 3.5)))))
     (Alto . ((dots . ((0 . 2.5)))))
     (Contralto . ((dots . ((1 . 2)))))
     (Tenor . ((dots . ((0 . 1.5)))))
     (Bass . ((dots . ((0 . 0.5))))))))

% The default Free Bass is modeled after the default Discant register
% description.
#(define defaultFreeBass
  '((glyph . "accordion.accFreebase")
    (reedbank
     (L . ((dots . ((0 . 0.5)))))
     (M . ((dots . ((0 . 1.5))))))
    (register
     ("1" (reedbanks L))
     ("10" (reedbanks M))
     ("11" (reedbanks L M)))))

#(define-macro (registerSetter name value)
  `(begin
    (define-markup-command (,name layout props name) (string?)
     (let* ((instrument ,value)
            (register (ly:assoc-get name (ly:assoc-get 'register instrument)))
            (reedbanks (ly:assoc-get 'reedbank instrument)))
      (interpret-markup layout props
       (let markup-builder ((dots
                             (or (ly:assoc-get 'dots register)
                              (append-map (lambda (x)
                                           (ly:assoc-get 'dots
                                            (ly:assoc-get x reedbanks)))
                               (ly:assoc-get 'reedbanks register))))
                            (result (markup #:musicglyph
                                     (ly:assoc-get 'glyph instrument))))
        (if (null? dots) result
         (markup-builder (cdr dots)
          (markup #:combine result
           #:translate (car dots) #:musicglyph "accordion.accDot")))))))
    (define ,name
     (define-music-function (parser position register) (string?)
      (make-music
       'TextScriptEvent
       'direction
       1
       'text
       (markup ,(symbol->keyword name) register))))))

#(registerSetter Discant defaultDiscant)
#(registerSetter Freebass defaultFreeBass)
#(registerSetter Stdbass defaultStdBass)

{ d'^\markup { \Discant #"12+1" }
  \clef bass \Freebass #"10" c
  <c e g>^\markup { \Stdbass #"Soft Bass" }
}


-- 
David Kastrup