Re: Generate music with scheme

[Aaron Hill]

On 2022-04-11 9:10 am, Henrik Frisk wrote:
> > \version "2.22.2"
> >
> > {
> >    $(make-sequential-music
> >      (map (lambda (x)
> >             (make-sequential-music
> >              (list
> >               (make-music 'NoteEvent
> >                           'pitch
> >                           (ly:make-pitch 0 x)
> >                           'duration
> >                           (ly:make-duration 2))
> >               (make-music 'MarkEvent
> >                           'label
> >                           (markup
> >                            #:line
> >                            (#:override (cons (quote font-size) -3)
> > "10"))))))
> >           (list 1 2 3 4)))
> > }
> Thanks Jean,
>
> It was the (make-sequential-music) after the lambda expression that I 
> had
> missed, without it it doesn't help to combine the two music events in 
> one
> list.

You could also use append-map which will concatenate the lists without 
the inner call to make-sequential-music:

%%%%
{
 $(make-sequential-music
  (append-map
   (lambda (x) (list
    #{ $(ly:make-pitch 0 x) 4 #}
    #{ \mark \markup \override #'(font-size . -3) 10 #} ))
   (iota 4 1)))
}
%%%%

In fact, using list-splicing, you can eliminate the outer call to 
make-sequential-music as well:

%%%%
{
 $@(append-map
  (lambda (x) (list
   #{ $(ly:make-pitch 0 x) 4 #}
   #{ \mark \markup \override #'(font-size . -3) 10 #} ))
  (iota 4 1))
}
%%%%

Also note the above use of #{ #} to escape music syntax within scheme, 
which can often be more abbreviated.


-- Aaron Hill