\version "2.11.46"

% This function is originally copied from mark-up-title (file scm/titling.scm), 
% which is lilypond's internal function to handle the title markups. I needed 
% to replace the scopes and manually add the $defaultheader (which is internally 
% done in paper-book.cc before calling mark-up-title. Also, I don't extract the 
% markup from the header block, but use the given markup.
%
% I'm not sure if I really need the page properties in props, too... But I 
% suppose it does not hurt, either.
#(define-markup-command (markupWithHeader layout props markup) (markup?)
  "Interpret the given markup with the header fields added to the props. 
   This way, one can re-use the same functions (using fromproperty 
   #'header:field) in the header block and as top-level markup."
  (let* (
      ; TODO: If we are inside a score, add the score's local header block, too!
      ; Currently, I only use the global header block, stored in $defaultheader
      (scopes (list $defaultheader))
      (alists (map ly:module->alist scopes))
  
      (prefixed-alist
        (map (lambda (alist)
          (map (lambda (entry)
            (cons
              (string->symbol (string-append "header:" (symbol->string (car entry))))
              (cdr entry)))
            alist))
          alists))
      (props (append prefixed-alist
              props
              (layout-extract-page-properties layout)))
    )
    (interpret-markup layout props markup)
  )
)

% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

% test markup containing references to header fields:
testMarkup = \markup {
  \justify {
    This is a text inserted using the new \typewriter{"\\markupWithHeader"} 
    command to allow using header fields 
    (via \concat{"\fromproperty #'header:fieldname").} For example, the title field 
    is \fontsize #+3 \fromproperty #'header:title and 
    the composer is \fontsize #+3 \fromproperty #'header:composer
  }
}

\header { 
  title="My own title" 
  composer="Someone" 
  piece = "Global piece name"
}

% Print out the markups. The \fromproperty #'header:field are now properly
% interpreted.
\markup\markupWithHeader \testMarkup

% Unfortunatly, I'm not able to directly pass a markup to the function????
%
% \markup\markupWithHeader \markup {
%   \wordwrap {
%     This is a long text, which is now able to use the header fields 
%     (via "\fromproperty #'header:fieldname"). For example, the title field 
%     of this score is: \fromproperty #'header:title and the composer is: 
%     \fromproperty #'header:composer
%   }
% }


% FIXME: How can I get the score object for markups inside a score, so that I 
%        can add the local header block to the properties, too?
scoreTestMarkup = \markup {Piece: \fontsize #+2 \fromproperty #'header:piece }
\score {
  \relative c'' { c1^\markup\markupWithHeader\scoreTestMarkup}
  \header { piece = "Local piece name" }
}