Re: Scheme in LilyPond

[Jan-Peter Voigt]

Hi Charles,

the make-note-ev function is hidden inside a closure and therefore not 
publicly visible. It depends on the duration defined in that closure. To 
create NoteEvents you should create them like this:

(make-music 'NoteEvent 'pitch root 'duration some-duration)

where 'some-duration' is defined with a duration: (ly:make-duration 2) 
for a quarter note.

The begin-define-sequence implies using 'let':

#(let ((root (ly:make-pitch 0 0 0))
       (dur (ly:make-duration 2)))
   (display (make-music 'NoteEvent 'pitch root 'duration dur)))

If there is a duration reachable in the scope you are acting, then you 
can use that one like you found in the mentioned file and probably copy 
the definition of make-note-ev.

HTH
Jan-Peter

Am 01.06.2017 um 17:03 schrieb Charles Winston:
> Hi,
>
> I’m fooling around with using Scheme in lilypond files, making some way on my 
> GSoC chords project. I’m trying to call the make-note-ev procedure found in 
> scm/chord-entry.scm on line 196. I’ve written something simple:
>
> #(begin
>         (define root (ly:make-pitch 0 0 0))
>         (display (make-note-ev root))
> )
>
> And I get an error saying that make-note-ev is an unbound variable. I thought 
> that we could call Scheme procedures from the source in lilypond files. What am 
> I missing here?
>
> Thanks,
> Charles
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