Re: chose module name instead of *anonymous-ly-NN*?

[Nicolas Sceaux]

Sat, 17 Apr 2004 12:45:34 +0200, Nicolas a dit : 

 > In the meantime I am trying some hacks to achieve the following:

 > (define (textoffset dx dy)
 >   #{ \property Voice.TextScript #'offset = #(cons $dx $dy) #})

 > that would expand in the following:

 > (define (textoffset dx dy)
 >   (ly:parse-string (format #f " \property Voice.TextScript #'offset = #(cons 
 > ~a ~a) "
 >                            dx dy)))

 > and returns, when called, the music expression with the appropriate
 > values inserted. I don't find it very eleguant, but it may be handy in
 > user lily code. (I don't think `$' is often used in lily files?)

 > nicolas

Here is a possible implementation, using the temp dirty
ly:parse-string

-------------------- scm/toto.scm ----------------------
(define-module (lily))
(export ly:parse-file)

(define-module (scm toto))
(use-modules (ice-9 format) (lily))

(define-public (ly:parse-string str)
  "Fake!"
  (let ((port (open-output-file "/tmp/tmplily.ly")))
    (format port "vartmp = \\notes { ~a }
#(export vartmp)
#(define-module (scm toto))
#(use-modules (ice-9 format) (*anonymous-ly-15*))~%" str)
    (close-port port)
    (ly:parse-file "/tmp/tmplily.ly")
    vartmp))

(define-public (read-lily-expression chr port)
  (let* ((format-args '())
         (lily-string (with-output-to-string
                        (lambda ()
                          (do ((c (read-char port) (read-char port)))
                              ((and (char=? c #\#)
                                    (char=? (peek-char port) #\}))
                               (read-char port))
                            (cond ((and (char=? c #\$)
                                        (not (char=? (peek-char port) #\$)))
                                   ;; a $variable
                                   (display "~a")
                                   (set! format-args (cons (read port) 
format-args)))
                                  ((and (char=? c #\$)
                                        (char=? (peek-char port) #\$))
                                   ;; just a $ character
                                   (display (read-char port)))
                                  (else
                                   ;; other caracters
                                   (display c))))))))
    `(ly:parse-string (format #f ,lily-string ,@(reverse! format-args)))))

(read-hash-extend #\{ read-lily-expression)
-------------------- scm/toto.scm ----------------------

---------------------- foo.ly --------------------------
#(use-modules (scm toto))

#(define (textoffset dx dy)
  #{ \override Voice.TextScript #'extra-offset = #(cons $dx $dy) #})

myoffset=#(textoffset 3 -4)
\score {
    \notes {
        c'^"normal text"
        %% uhrg, I cannot write scheme here
        %% #(textoffset 3 -4)
        \myoffset
        c'^"text with offset"
    }
}
---------------------- foo.ly --------------------------

which gives the expected result.
(this example is not exactly convincing)