Re: \transpose of drum voices

[Jay Anderson]

On Sun, Aug 28, 2011 at 9:03 PM, Fernando <address@hidden> wrote:
> Is it possible to use \transpose for patterns written in \drummode ?

Here's something that I might do:
==============================
\version "2.14.2"

drumSwap =
#(define-music-function (parser location from to music) (symbol?
symbol? ly:music?)
  (define (swap-drum-type mus)
    (if (and (eq? (ly:music-property mus 'name) 'NoteEvent)
             (eq? (ly:music-property mus 'drum-type) from))
      (ly:music-set-property! mus 'drum-type to))
    mus)
  (music-map (lambda (x) (swap-drum-type x)) music))

drumMus = \drummode
{
  sn4 sn sn sn
}

\score
{
  <<
    \new DrumStaff \drumMus
    \new DrumStaff \drumSwap #'snare #'bassdrum \drumMus
  >>
}
==============================

It simply swaps all of one type for another. Look up the symbols for
the drum pitches in drumpitch-init.ly.

-----Jay