Re: Scoping problem in define-music-function

[David Kastrup]

Marc Hohl <address@hidden> writes:

> Hello list,
>
> thanks to Reinhold Kainhofer and Wilbert Berendsen I managed to get a
> callback with an
> additional argument.
>
> Now I want to write a music function like this:
>
> myFunction = #(define-music-function parser location fret music)
> (string? ly:music?)
>  (let (( ... some expressions ... ))
>
>  #{
>     \override TabNoteHead #'stencil = #(my-special-callback fret)
>  #}
>  (..some more scheme stuff working on music...)
>  #{
>     \revert TabNoteHead #'stencil
>  #}
> ))
>
> but lilypond complains with
>
> <string>:2:46: Fehler: GUILE signalisierte einen Fehler für den hier
> beginnenden Ausdruck
>    \override TabNoteHead #(quote stencil) = #
>                                              (my-special-callback fret)
> Unbound variable: fret
>
> So fret is not known within #{ ... #}.
>
> Is there a way to define the function in an appropriate way? It
> doesn't matter if the given variable fret is an argument to the music
> function or calculated within the let-block.

Uh, $fret ?

-- 
David Kastrup