[Scheme-reports] Can a library keep state?

[Jeronimo Pellegrini <j_p@x>]

Hello,

The report mentions that

 "In a library declaration, it is an error to import
 the same identifier more than once with different bindings,
 or to redefine or mutate an imported binding with define,
 define-syntax or set!."

So a library cannot, for example, export a variable that
is supposed to be mutated by the user. But can it export
a getter and a setter?

(define-library (foo bar)
  (import (scheme base))
  (export get-x set-x!)
  (begin
    (define x 0)
    (define (get-x) x)
    (define (set-x! z) (set! x z))))


 > (import (foo bar))
 > x
 ERROR: undefined variable: x
 > (get-x)
 0
 > (set-x! 10)
 > (get-x)
 10

This works in Chibi (and I'd use this a lot!) -- but it's
not explicitly allowed by the standard, so I'm checking.
Is this the intended semantics? (If it is, I'm happy!)

Thanks,
J.


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