"include" music-function

[Jan-Peter Voigt]

Dear lily-list-members,

first of all: A happy new year!

In my projects I often combine several files, each containing one piece, 
to a book.
In fact, I store the music in a scheme-based structure to instantiate it 
later.
The included files shall intentionally not create a PDF, so that 
instantiation can be organized in bookparts as needed.
But when I work on a specific piece I want to debug it without compiling 
the whole book.
One solution would be to use frescobaldi and a comment %%master: 
../<main>.ly at the end of the file. But then I have to create a 
master-file for each part.
So I created a music-function to include a testfile wich contains 
instructions to instantiate the music stored in my structures only if I 
am compiling this file directly:
--snip--
#(define-public includeLocal (define-music-function (parser location 
file)(string?)
    (let ((outname (format "~A.ly" (ly:parser-output-name parser)))
          (locname (car (ly:input-file-line-char-column location))))
         (if (or (string=? outname locname)(string-suffix? outname 
locname))
             (let ((content (ly:gulp-file file)))
                  (ly:parser-include-string parser content)))
         (make-music 'SequentialMusic 'void #t))))

\includeLocal "test.ly"
--snip--
This function first compares the outname with the location name and only 
includes the file if they match. (This should not work, if you have set 
some output-suffix!)

This is a usable solution to me. But I would like to have the correct 
location info available, while parsing the included file.
Is it possible to create an arbitrary "include"-music-function? This 
would make it possible, to (for example) include all files in a 
directory or matching a specific pattern.

Cheers,
Jan-Peter