Creating a callback with an additional argument?

[Marc Hohl]

Hello list,

is it possible to create a callback with an additional argument?

I tried

#(define-public (my-callback string grob)
...
..
)

and wanted to call it by

\override Notehead #'stencil = #my-callback #'foo'

but lilypond complains.

Is this possible at all or do I have to use another mechanism?

Marc