Re: Odd interaction between ly:grob-property and hairpin

[Aaron Hill]

On 2022-02-09 5:15 pm, Simon Albrecht wrote:
> Hello list,
>
> if a grob callback queries a grob property on a hairpin as follows,
> the hairpin gets printed infinitely short (with a corresponding
> warning: crescendo too small):

A pure vs. unpure issue perhaps?  If you use ly:grob-pure-property to 
access it, it seems to work.

%%%%
\version "2.22.0"

off =
#(define-event-function
  (ev) (ly:music?)
  (define (offsetter-fn grob)
   (format #t "\nY-offset=~s"
    (ly:grob-pure-property grob 'Y-offset 0 0 0))
   (ly:grob-set-property! grob 'color red))
  #{ \tweak before-line-breaking #offsetter-fn $ev #})

{
  2\off \< 2\f
  2\tweak Y-offset #-0.5 \off \< 2\f
  2\offset Y-offset #0.5 \off \< 2\f
}
%%%%


-- Aaron Hill