Halfprall and accidentals

[Hans Aberg]

Using the before mentioned Unicode font Euterpe and the Unicode  
character U+1D19D (written \U1D19D below) in it, I was able to create  
an ornament sign similar to \prall (but shorter) using the definition
  halfprall=^\markup {\override #'(font-size . 3.5) {\U1D19D}}

However, when combining an accidental, as say in b^\halfprall^\sharp,  
the accidental may erratically end up below, different uses on long  
distances may influence each there.

So I suspect I should define a proper markup object, as in the file  
script.scm, which defines
(define-public default-script-alist
  '(...
    ("prall" .
     ((script-stencil . (feta . ("prall" . "prall")))
      (padding . 0.20)  
      (avoid-slur . around)
      (direction  . 1)))
     ...
But I am not sure exactly how to do that for the character U+1D19D.

And it would be nice to define a markup similar to b-., but with the  
"." replaced by U+1D19D, which then should expand to \halfprall. Is  
that possible?

  Hans Åberg