[EMAIL PROTECTED] writes:
> Should result in about the same thing as this:
>
> ---
> \notes \context Voice \relative c' { c4. d8 e4. f8 g4. a8 b4. c8 }
> ---
>
> Just to test things, I defined the function 'combine-dur' like this:
>
> ---
> #(define (combine-dur x)
> (display "\n===\n")
> (let ((a (ly-get-mus-property x 'elements)))
> (display (car a))
> (display "\n===\n")
> (display (cadr a))
> )
> x)
> ---
>
> I noticed by looking at what displayed that (car a) was the
> \myduration sequence and (cadr a) was \music. However, the two
> resulting sequences do not act like ordinary lists, and normal mapping
> functions do not work. In addition, (car a) is the unevaluated form
> of \myduration, with information about how many times to repeat but the
> repeats themselves not unfolded.
>
> At this point I'm at a total loss. Are (car a) and (cadr a) both
> valid types of music?
(ly-get-mus-property mus 'elements) returns a possibly non-empty list
of music objects.
(ly-get-mus-property mus 'element) returns () or a music object.
You should always recurse on both, since constructs like \context
Voice layer another Music object over their arguments.
> If so, why do they return () for every call to
> ly-get-mus-property? Can I evaluate nested sequences like nested
> lists? Is there a better way to do all this?
Repeats happen in interpreting, i.e. after \apply is done, so what you
want can not be done. Better write two functions
(apply-duration-to-note mus dur)
and
(apply-durations-to-sequence muslist durlist)
use these to write a function that is called like
\apply #(lambda (x) (apply-durations-to-sequence
(ly-get-mus-property x 'elements) (list
(make-duration 2 1) ;; dotted quarter
(make-duration 3 0) ;; eighth
))
The apply-durations-to-sequence should loop through its 2nd argument
for setting durations. When you go this route, be sure to be careful
with nesting other music in the { } .
Btw, if you finish the code, could we include it in the examples?
--
Han-Wen Nienhuys | [EMAIL PROTECTED] | http://www.cs.uu.nl/~hanwen
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