On Wed, Dec 15, 2010 at 11:35:32AM -0700, Carl Sorensen wrote:
> On 12/15/10 9:29 AM, "Juha Erkkila" <j...@turnipsi.no-ip.org> wrote:
> > Is it possible to define functions that generate music functions
> > in Lilypond? I'm looking something to this effect:
> >
> > -----
> > \version "2.12.3"
> >
> > musicA = #(define-music-function (parser location music)
> > (ly:music?)
> > #{ c4 d e f $music #})
> >
> > \musicA { g4 a b a }
> >
> > % makeMusicFn = #(define-music-function (parser location prepend-music)
> > % (ly:music?)
> > % (define-music-function (parser location append-music)
> > % (ly:music?)
> > % #{ $prepend-music $append-music #}))
> > %
> > % musicB = \makeMusicFn { c4 d e f }
> > %
> > % \musicB { g4 a b a }
> > -----
> >
> > Here expressions "\musicA { g4 a b a }" and "\musicB { g4 a b a }"
> > should evaluate to same music expression, that is
> > { c4 d e f g4 a b a }. The expressions that are commented out are
> > attempts to achieve what I'm looking for. The above syntax is,
> > however, wrong, as define-music-function must return a music
> > expression, not a function.
>
> Music functions must return music expressions, but scheme functions can
> return functions.
>
> Are you after this specific behavior, or some other behavior, of which this
> is a simplified example?
The above was just a simplified example, the actual case I try to
do is more complex. Anyway, this solution is enough for me:
-----
\version "2.12.3"
musicA = #(define-music-function (parser location music)
(ly:music?)
#{ c4 d e f $music #})
\musicA { g4 a b a }
#(define (musicFn prepend-music)
(ly:make-music-function (list ly:music?)
(lambda (parser location append-music)
#{ $prepend-music $append-music #})))
musicB = #(musicFn #{ c4 d e f #})
\musicB { g4 a b a }
-----
Thanks for the tips. It's good to see scheme and lilypond play
together so nicely!
Juha
_______________________________________________
lilypond-user mailing list
lilypond-user@gnu.org
http://lists.gnu.org/mailman/listinfo/lilypond-user
