\version "2.19.82"


% What do you want to achieve with this function?

% return an object containing markup and score
exampleA =
#(define-scheme-function ()()
   ; create a
   (list
    (cons
     'mup
     #{
       \markup "Test"
     #})
    (cons
     'mus
     #{
       \score {
         c'4
       }
     #})
    ))

exA = \exampleA

\exA.mup
\exA.mus

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% add the markup and the score immediatly
exampleB =
#(define-scheme-function () ()
   (add-score
    (list #{
      \markup "Test"
      #}))
   (add-score
    #{
      \score {
        c'4
      }
    #}
    ))

\exampleB


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% return a function that adds markup and score
exampleC =
#(define-scheme-function (mup mus) (markup? ly:score?)
   (define-void-function ()()
     (add-score
      (list mup))
     (add-score mus)
      ))

exC = \exampleC Test \score { c'4 }

\exC