[R6RS] libraries

[dyb at cs.indiana.edu]

> > What about:
> >
> >   (library S "scheme://r6rs"
> >     (export P! s)
> >     (define s '())
> >     (define-syntax P!
> >       (syntax-rules ()
> >         [(_ x y) (set! x (cons y x))])))
> >   (library T "scheme://r6rs"
> >     (import S)
> >     (export P0!)
> >     (define (P0!) (P! s 0)))
> >
> > Is this okay too?
>
> I'd say no.
>
> > The set! is contained within S.
>
> But the reference to `s' isn't.

Good point---I think I understand your criteria.  Would this be okay,
then?

  (library S "scheme://r6rs"
    (export A P! s)
    (define s '())
    (define-syntax A
      (syntax-rules ()
        [(_ p x) (p s x)]))
    (define-syntax P!
      (syntax-rules ()
        [(_ x y) (set! x (cons y s))])))
  (library T "scheme://r6rs"
    (import S)
    (export P0!)
    (define (P0!) (A P! 0)))

I assume so, since both the set! and reference to 's' are within S.

Kent