Re: duration-length becomes duration-moment, but script no longer works

On Wed, 2026-08-12 at 15:43 +0200, Lukas-Fabian Moser wrote:
> Dear Richard,
> 
> Am 12.08.26 um 12:35 schrieb Richard Shann:
> > > Could you please provide the original, working (with an older
> > > LilyPond
> > > version) state of your code before convert-ly changed it?
> > Thank you for getting back to me:
> > 
> > This is the code working in 2.24
> 
> Ah, I see. That code makes assumptions on the internal representation
> of 
> grace music that are no longer valid in 2.26.
> 
> But the original code is also more involved than necessary. If I'm
> not 
> mistaken, it can be replaced by something as simple as:
> 
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> \version "2.24"
> 
> #(define (after-grace-factor? x)
>     (and (rational? x)
>          (< 0 x 1)))
> 
> #(define (grace-music? m)
>     (and (ly:music? m)
>          (music-is-of-type? m 'grace-music)))
> 
> attachGraces =
> #(define-music-function (frac note graces) (after-grace-factor? 
> ly:music? grace-music?)
>      #{
>        <<
>          #note
>          {
>            \skip $(make-duration-of-length (ly:music-length note)) *
> #frac
>            #graces
>          }
>        >>
>      #})
> 
> \score {
>    \new Staff
>    {
>      \attachGraces #3/4 g''4 \grace { f'8 }
>    }
> }
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> 
> Incidentally, this version should work out of the box in 2.26 as in 
> 2.24. It behaves a bit differently from your original, though: Your 
> original (I think) strips away the additional code that make up, for 
> instance, an \appoggiatura in contrast to a simple \grace. The code
> I'm 
> proposing doesn't touch the inner structure of the grace music.

That seems to work just fine, both in 2.24 and 2.26. I haven't heard of
people trying to use it on appogiaturas - I think the main application
is in 18th c music before they came in. So this is probably a benefit.

> 
> But actually, are you aware that stock LilyPond \afterGrace accepts
> an 
> optional argument that (I think) does just what your code achieves, 
> without you having to enter \grace explicitly? Try:
> 
> \afterGrace #3/4 g''4 f'8

I noticed that while digging around; I guess the problem is that it
might be difficult for Denemo to make sense of that syntax without
coding something up in C for it (because when you get to the grace note
it doesn't announce that it _is_ a grace note)

Thanks very much for this fix.
You also tipped me off about the use of (_ string) -  
I've tested out the G_ and have run into problems - despite (version)
reporting => 3.0.8 and the documents even for guile 2 saying G_ is the
conventional shorthand for gettext I get a "possibly unbound variable
`G_' " warning from using it. I guess I can always just define it.

Thank you once more,

best wishes

Richard