Re: smart transpose

[Mats Bengtsson]

> > I think it would be better to use the builtin transpose function
> > and implement a Scheme function 'simplify' that makes the desired
> > enharmonic changes, something like
> > \apply #simplify \transpose cs' \music
> > I don't have the time right now to implement it, but some
> > Scheme hacker on the list should be able to do it.
> > This function might be useful also in other situations where you
> > don't want to transpose but the composer wrote something unreadable.

I actually implemented the 'simplify' function, see the attached file.
However, there are some problems left. If you have the music, 
{\key d \major bs1 | cs} and apply the function simplify you will get 
{\key d \major c1 | cs} without a reminder on the c sharp. I leave it
as a challenge to some Scheme hacker to automatically insert reminder
accidentals in situations like this, i.e. to produce 
{\key d \major c1 | cs!}. You see this problem at several places in your
example.

> > On the other hand, I find it confusing to see an 'f' instead of
> > an e sharp if the melodic function of the note is e sharp, but
> > that's individual and probably also dependent on the instrument.
> 
>       Maybe but I just need to give score to my friend in order to say "let's 
> play".

If you gave it to me, I would find it much easier to sight-read the
first version than the second version in the attached example.


I replaced the whole notes by half notes in the example (except for 
the last one which I replaced with two tied half notes (yet another
alternative that may be what you really want).

> > Also, you may want to use ties for tied-over notes,
> > for example df8 ~ df4 instead of df8( )df4

I replaced some slurs with ties as well.


   /Mats

\include "english.ly"
\header {
         "composer" = ""
         "title" = "Bb Minor Bulgar"
         }

#(define  (unhair-pitch p)
  (let* ((o (pitch-octave p))
         (a (pitch-alteration p))
         (n (pitch-notename p)))

    (cond
     ((and (> a 0) (or (eq? n 6) (eq? n 2)))
      (set! a (- a 1)) (set! n (+ n 1)))
     ((and (< a 0) (or (eq? n 0) (eq? n 3)))
      (set! a (+ a 1)) (set! n (- n 1))))

    (cond
     ((eq? a 2)  (set! a 0) (set! n (+ n 1)))
     ((eq? a -2) (set! a 0) (set! n (- n 1))))

    (if (< n 0) (begin (set!  o (- o 1)) (set! n (+ n 7))))
    (if (> n 6) (begin (set!  o (+ o 1)) (set! n (- n 7))))

    (make-pitch o n a)))

#(define (simplify music)
  (let* ((es (ly-get-mus-property music 'elements))
         (e (ly-get-mus-property music 'element))
         (p (ly-get-mus-property music 'pitch))
         (body (ly-get-mus-property music 'body))
         (alts (ly-get-mus-property music 'alternatives)))

    (if (pair? es)
        (ly-set-mus-property
         music 'elements
         (map (lambda (x) (simplify x)) es)))

    (if (music? alts)
        (ly-set-mus-property
         music 'alternatives
         (simplify alts)))

    (if (music? body)
        (ly-set-mus-property
         music 'body
         (simplify body)))

    (if (music? e)
        (ly-set-mus-property
         music 'element
         (simplify e)))

    (if (pitch? p)
        (begin
          (set! p (unhair-pitch p))
          (ly-set-mus-property music 'pitch p)))

    music))


        
music = \notes  
        \relative c'
        {
          \time 2/4
          \key df \major
        \tempo 4=180
        \partial 8 
        f8
        \repeat "volta" 2 {
                [e8 f gf f] | [df a bf b] | c2 ~| c4 r8 f8 |
                [e8 f gf f] | e8 df16 e \times 2/3 {df8 c bf} | c8 df ~ df4 ~ | 
df4 r8 f8 |
                [e8 f df' a] | [bf f gf d] | ef2 | gf4. f8 | [gf8 f e f] | [df' 
c f, c'] | 
        }
                \alternative { {bf2( | )b4 r8 f8} {bf4 a | af4. af8} } 
        
        \repeat "volta" 2 {
                df,8. f16 af8 df | [af8 f df ef] | f2 | r8 [af,8 bf c] |
                df8. f16 af8 df | [af8 f df ef] | gf4. ef16 f | \times 2/3 {gf8 
f ef} \times 2/3 {df8 c bf} |
                af8. bf16 c8 df | [ef8 c bf' a] | a2 | g2 | \times 2/3 {gf8 f 
ef} \times 2/3 {bf'8 af gf} |
                \times 2/3 {ef' df c} bf8 c |
                }
                \alternative { {df2 | r8 af,8 bf c} {df8. df16 ef8 e | [f8 f, g 
a]} }

        \repeat "volta" 2 {
                b2 | r8 [a8 bf b] | c2 ~ | c2 | c2 | r8 c8 ef d | df2 | r8 [a8 
bf f] | gf8 gf ef4 | r8 [a8 bf gf]
                f8 f df4 | r8 [df8 c bf] | [c df e f] | e8. df16 c8 df
                }
                \alternative {{bf2 | r8 [f'8 g a] }{bf2 ~ | bf( | )b4. s8}} 
        }
\score {
     \notes \context Staff { 
     \transpose cs' \music
     \apply #simplify \transpose cs' \music
%       \apply #(lambda (x) (smart-transpose x (make-pitch 0 0 1)))
%       \music
}
\paper{
 \translator {
       \ScoreContext
       SpacingSpanner \override #'arithmetic-basicspace = #3
        }
}
\midi{}
}