Using define-music-function

[Ralph Little]

Hi,
I'm using 2.9.16 on Windows and I'm getting into scheme and more complex stuff
now I have some time.
I am trying some of the define-music-function examples from the doc but Lilypond
can't seem to find the function.

I get:
=======================================================
GNU LilyPond 2.9.16
Processing `blob.ly'
Parsing...ERROR: Unbound variable: def-music-function
=======================================================

I found a definition for the function in music-functions.scm and tried to
include that, but it generated another error:

=======================================================
GNU LilyPond 2.9.16
Processing `blob.ly'
Parsing...
C:/Program Files/LilyPond/usr/bin/../share/lilypond/current/scm/

;;;; music-functions.scm --ERROR: Unbound variable: :optional
=======================================================

I must be doing something really stupid :(

Could anyone point me in the right direction?

Cheers,
Ralph Little