Re: Instanciable scheme engraver (issue216066)

[David Kastrup]

address@hidden writes:

> Reviewers: ,
>
> Message:
> Hi,
>
> This is a proof-of-concept for instanciable scheme engravers, with
> private instance slots.
>
> There is at least one issue that I have to solve before this is
> commitable, as this shows the following warning:
>
> Warning : Attempting to remove nonexisting listener.
> Warning : Attempting to remove nonexisting listener.

Not a problem with your code, I guess, since you get the warning with
the old code and the following naively reduced source as well:

\layout {
  \context {
    \Voice
    \consists
    #(let ((instance-counter 0))
         (set! instance-counter (1+ instance-counter))
         (let ((instance-id instance-counter)
               (private-note-counter 0))
           `((listeners
              (note-event
               . ,(lambda (engraver event)
                   (set! private-note-counter (1+ private-note-counter))
                   (let ((text (ly:engraver-make-grob engraver 'TextScript  
event)))
                     (ly:grob-set-property! text 'text
                                            (format "~a.~a" instance-id
                                                     
private-note-counter)))))))))
  }
}

<<
  \relative c'' { c4 d e f }
  \\ \relative c' { c4 d e f }
>>

-- 
David Kastrup