Re: rhythm shift

[Gilles THIBAULT]

> \time 2/4
> r4 a4 ~ |
> a4 b4 ~|
> b4 r4

> How can I shift (convert) it to:
> \time 2/4
> a2 |
> b2 |
> r4

For "shifting" rhythm, you can use this snippet :
http://lsr.di.unimi.it/LSR/Item?id=542

To transform 2 tied notes into a single note, you have to make your own 
function...

----------------------------------------------------------------------------

\include "extractMusic.ly"
%% to download here
%% http://gillesth.free.fr/Lilypond/extractMusic/

#(define (name-of music)
 (ly:music-property music 'name))

%% TODO: this function probably does not work with chords -:(
twoTiedNotesToOneNote = #(define-music-function (parser location music) 
(ly:music?)
"Transform 2 tied notes in a note with a length equal to the sum of their 
lengths"
 (let loop ((notes (reverse ;; easier for managing multiple tied notes)
                     (extract-named-music music 'NoteEvent ;; 'EventChords 
                       ))))
   (if (or (null? notes)(null? (cdr notes)))
     (music-filter (lambda(mus)(not (eq? 'Music (name-of mus))))
                   music)
     (let ((note1 (first notes))
           (note2 (second notes)))
       ;; (display "-------------"\n)
       ;; (display-scheme-music note1) 
       ;; (display-scheme-music note2)      
       (if (pair? (extract-named-music note2 'TieEvent))
         (let* ((mom1 (ly:music-length note1))
                (mom2 (ly:music-length note2))
                (new-mom2 (ly:moment-add mom1 mom2))
                   ;; the following moment->rhythm function 
                   ;; is defined in "extractMusic.ly"
                (new-dur2 (moment->rhythm new-mom2)))
           (ly:music-set-property! note2 'duration new-dur2)
           (ly:music-set-property! note2 'articulations 
             (filter (lambda(mus)(not (eq? 'TieEvent (name-of mus))))
                     (ly:music-property note2 'articulations)))
           ;; (set! note1 (ly:make-music 'Music)) ;; doesn't work...
           (ly:music-set-property! note1 'name 'Music))) 
               ;; well, changing the property 'name is not "standard"
       (loop (cdr notes))))))

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


music = { 
  \time 2/4
  r4 a4-"4" ~ 
  a4-"3" b4-"2" ~
  b4-"1" r4 
}


\new Staff \music
\new Staff { 
  \time 2/4
  \extractEnd
     \twoTiedNotesToOneNote \music
     s4

}

music = \relative c' {  
s2. s8. d16 ~  % 31
d8. d16 ~ d8 b'16 b16 ~ b16 b8 b16 ~ b16 b8 b16 ~  % 32
b8 a16 g16 ~ g4
}

\new Staff \music
\new Staff { 
  \extractEnd
     \twoTiedNotesToOneNote \music
     { s2. s8.  }

}
--------------------------------------------------------------

Note that if you "shift" rhythm, you have to delete barcheck |

-- 
Gilles