create custom context definitions using a scheme function

[Janek Warchoł]

Hi,

I want to create custom context definitions using a scheme function.
Later on the function will take some arguments and actually do
something interesting, but right now i cannot get the most basic
examples to work:

%%%%% why the override isn't applied here?

test =
#(define-scheme-function (parser location)()
   #{
     \layout {
       \context {
         \Staff
         \override NoteHead #'color = #blue
       }
     }
   #})

\layout { \test }

% this doesn't work either:
%\test

melody = \relative c'' {
  c b a f
}

\score {
  \new Staff \melody
}


%%%%%%%%%%%%%%%%%%%%
% another snippet. why this doesn't work?

test =
#(define-scheme-function (parser location)()
   #{
     \layout {
       \context {
         \ChoirStaff
         \accepts "TestStaff"
       }
       \context {
         \Staff
         \name "TestStaff"
         \alias "Staff"

         instrumentName = "Lol"
       }
     }
   #})

\layout { \test }

% this doesn't work either:
%\test

melody = \relative c'' {
  c b a f
}

\score {
  \new ChoirStaff <<
    \new TestStaff \melody
  >>
  \layout {
    \override TestStaff.NoteHead #'color = #blue
  }
}