Smart transpose

[Han-Wen Nienhuys]

address@hidden writes:
> I've just entered a request on cosource.com :
> 
>         http://www.cosource.com/cgi-bin/cos.pl/wish/info/387
> 
> Here's a copy of my feature request :
 
> Your task, if you accept it is to implement a \smarttranspose command
> that would translate such oddities into more natural notations. Double
> accidentals should be removed, as well as #E (-> F), bC (-> B), bF (->
> E), #B (-> C).

You mean like this. (Sorry 'bout the nuked indentation.)

#(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 7) (begin (set!  o (+ o 1)) (set! n (- n 7))))

     (make-pitch o n a)
     ))

#(define (smart-transpose music pitch)
         (let* ((es (ly-get-mus-property music 'elements))
               (e (ly-get-mus-property music 'element))
                  (p (ly-get-mus-property music 'pitch))
                     (boddhi (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) (smart-transpose x pitch)) es))
                        )
                        (if (music? alts)
                            (ly-set-mus-property music 'alternatives
                    (smart-transpose alts pitch)))
                    (if (music? boddhi)
                        (ly-set-mus-property music 'body
                    (smart-transpose boddhi pitch)))

                    (if (music? e)
                        (ly-set-mus-property music 'element
                        (smart-transpose e pitch)))
                        (if (pitch?  p)
                            (begin
                                  (set! p (unhair-pitch
                        (Pitch::transpose p pitch)))
                              (ly-set-mus-property music 'pitch p)
                                    ))
                                    music
))


m =   \notes \relative c' { c4 d  e f g a b  c }
\score {
       \notes \context Staff  { \transpose ais' \m
         \apply #(lambda (x) (smart-transpose x (make-pitch 0 5 1)))
\m
        }
}


Add IMPLEMENT_TYPE_P(Music, "music?"); to music.cc, and presto, done.


That's an easy $ 100; if I'd make $ 200/hour for every hour
I worked on Lily, I'd be very rich :) 



-- 

Han-Wen Nienhuys   |   address@hidden    | http://www.cs.uu.nl/~hanwen/