On Sun, Nov 22, 2015 at 2:15 PM, Thomas Morley <thomasmorle...@gmail.com>
wrote:
> 2015-11-22 20:49 GMT+01:00 David Nalesnik <david.nales...@gmail.com>:
> >
> >
> > On Sun, Nov 22, 2015 at 1:21 PM, David Kastrup <d...@gnu.org> wrote:
> >>
> >>
> >> > Is there any way to get the override to be reevaluated with each
> repeat?
> >>
> >> No. Written in that manner, the override is evaluated at _input_ time.
> >> If you put it in a variable and use that variable 3 times, the colors
> >> will be the same each time. What you want is
> >>
> >> #(define test
> >> (let ((colors (circular-list red green blue yellow darkgreen
> magenta)))
> >> (lambda (grob)
> >> (let ((color (car colors)))
> >> (set! colors (cdr colors))
> >> color))))
> >>
> >> and
> >>
> >> \override NoteHead.color = #test
> >>
> >> That way you'll get one call per actual _grob_ since then each grob is
> >> then initialized with the callback, and the callback is replaced by the
> >> value when the property is first used.
> >>
> >
> > OK, I get it. I need to override NoteHead.color with a procedure, rather
> > than the evaluation of the procedure. (And a grob callback must of
> course
> > have a grob argument. Passing my original as a procedure results in an
> > error.)
> >
> > Thanks so much!
> >
> > David
>
>
>
> Though, why it is that arbitrary?
>
> Look at this variation and the attached image:
>
> \version "2.19.29"
> #(define test-nmbrs
> (let ((nmbrs (circular-list 1 2 3 4)))
> (lambda (grob)
> (let ((n (car nmbrs)))
> (set! nmbrs (cdr nmbrs))
> (grob-interpret-markup grob (number->string n))))))
>
> {
> \repeat unfold 8 {
> \once \override TextScript.stencil = #test-nmbrs
> c''4^\markup "foo"
> }
> }
>
>
And \tweak produces bizarre results with the color function. Try:
{
\repeat unfold 50 {
\tweak NoteHead.color #test c''4
}
}
DN
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