Re: question about minor + fourth

[Thomas Morley]

2016-08-28 10:33 GMT+02:00 Thomas Morley <address@hidden>:
> 2016-08-28 8:19 GMT+02:00 David Kastrup <address@hidden>:
>> Thomas Morley <address@hidden> writes:
>>
>>> 2016-08-28 0:19 GMT+02:00 Benjamin Poly <address@hidden>:
>>>> Thanks for the code you sent me in private Jacques, it's full of useful
>>>> examples but I still can't make this particular chord work.
>>>>
>>>> I want to display a minor chord with a fourth like this: "Am (add4)". 
>>>> That's
>>>> all I want to do.
>>>> First I'm surprised that I have to specify the chord (in the variable
>>>> chExceptionMusic) in a note to note format (in this case <a c e d>). Is it
>>>> not possible to specify it in a chord name format ?
>>>
>>> You would need to do it in \chordmode but there the "-"-sign has a
>>> different meaning,
>>
>> One can use _ here I guess.  Unpretty, yes.
>
>
> An in-ly-file proof of concept:
[...]

Here a more elaborate code, which could probably replace current
state. Works with default note-mode and chordmode, even mixed.
Though, questions in-line, anyone with some hints?

\version "2.18.2"

%%;; fixme we should standardize on omit-root (or the other one.)
%%;; perhaps the default should also be reversed --hwn
#(define (my-sequential-music-to-chord-exceptions seq . rest)
  ;; TODO change doc-string
  "Transform sequential music SEQ of type <<c d e>>-\\markup{ foobar }
to (cons CDE-PITCHES FOOBAR-MARKUP), or to (cons DE-PITCHES
FOOBAR-MARKUP) if OMIT-ROOT is given and non-false.
"

  (define (chord-to-exception-entry m)
    (let* ((omit-root (and (pair? rest) (car rest)))
           (pitches (event-chord-pitches m))
           (sorted (sort pitches ly:pitch<?))
           (root (car sorted))

           ;; ugh?
           ;;(diff (ly:pitch-diff root (ly:make-pitch -1 0 0)))
           ;; FIXME.  This results in #<Pitch c> ...,
           ;; but that is what we need because default octave for
           ;; \chords has changed to c' too?
           (diff (ly:pitch-diff root (ly:make-pitch 0 0 0)))
           (normalized (map (lambda (x) (ly:pitch-diff x diff)) sorted))
;; Question
;; why this mapping? Obviously `text' selects from this list, but why? --harm
           (texts
             (map
               (lambda (x) (ly:music-property x 'text))
               (extract-typed-music m 'text-script-event)))
           (text (if (null? texts) #f (if omit-root (car texts) texts))))
      (cons (if omit-root (cdr normalized) normalized) text)))

;; Question
;; is it really needed to check for ZERO-MOMENT? --harm
  (define (is-sane-ev-chrd? m)
     (not (equal? ZERO-MOMENT (ly:music-length m))))

  (let* ((elts (filter is-sane-ev-chrd? (extract-typed-music seq 'event-chord)))
         (alist (map chord-to-exception-entry elts)))

;; Question
;; why this filtering? Looks strange, and I see no difference --harm
    ;(filter (lambda (x) (cdr x)) alist)
    alist))

%%%%%%%%%%%%%%%%%%%%%%%%
%% EXAMPLE
%%%%%%%%%%%%%%%%%%%%%%%%

%% define the new behaviour
chExceptionMusic = {
  <c e g b>1-\markup { \super "7<" }
  \chordmode {
    a1:m4.5_\markup { m (add 4) }
    c1:6_\markup { \super "major plus 6" }
  }
  <c e g b d'>1-\markup { \super "major9" }
}

%% add it to other exceptional settings
chExceptions =
#(append
  (my-sequential-music-to-chord-exceptions
    chExceptionMusic
      #t)
  ignatzekExceptions)

m = \chordmode { c:7+ a:m4.5 c:6 c:7+.9 }

<<
  \new ChordNames
    %% use the new appearance in this context
    \with { chordNameExceptions = #chExceptions }
    \m
  \new Staff \m
>>

Cheers,
  Harm