[CM] R7RS support

[Rudolf Adamkovič]

bil at ccrma.Stanford.EDU writes:

> Thanks.  (*s7* 'filenames) should be (*s7* 'file-names).
> If you don't want the libc stuff, just comment out the
> (require libc.scm) at the top of the file.  I didn't
> realize that r7rs thinks current-output-port is a built-in
> parameter object.  It isn't in s7 -- sorry.

Got it.  Thanks so much!

FYI, we still do not use the official s7 import code because it does not
take into account [module] directories.  While R7RS says nothing about
it, e.g. Guile interprets library names such that library '(A B-C
D-E-F)' resides in file 'A/B-C/D-E-F.scm'.

I hacked the directory support in as follows:

;; Return the name of the file containing the LIB.  For example, we
;; expect the library (A B-C D-E-F) in the file A/B-C/D-E-F.scm.
(define (library-file lib)
  (let* ((chars-old (string->list (object->string lib)))
         (chars-new
          (let recur ((chars chars-old))
            (if (null? chars) chars
                (let* ((old (car chars))
                       (new (cond ((or (char-alphabetic? old)
                                       (char-numeric? old)
                                       (char=? old #\-)) old)
                                  ((char-whitespace? old) #\/)
                                  (else #f))))
                  (if new
                      (cons new (recur (cdr chars)))
                      (recur (cdr chars))))))))
    (string-append (list->string chars-new) ".scm")))

This brings s7 *much* closer to others, and we can now run unit tests on
both s7 and Guile side-by-side!  Perhaps s7 should do this out of the
box?

P.S. 1/2: 'r7rs.scm' needs a dummy definition for the '(scheme
process-context)' library.  Without it, anything with e.g. 'exit' breaks
for no good reason.

P.S. 2/2: Speaking of ports [in the original message], I found that the
following code does not say "hi" in s7 for some reason:

(display "hi" (current-error-port))
(flush-output-port (current-error-port))
(exit 1)

Thank you again for all your help!

Rudy
-- 
"Thinking is a momentary dismissal of irrelevancies."
-- Richard Buckminster Fuller, 1969

Rudolf Adamkovič <salutis at me.com> [he/him]
Studenohorská 25
84103 Bratislava
Slovakia