Re: A plea for local-eval in 2.0.4

[David Kastrup <dak@gnu.org>]

David Kastrup <dak@gnu.org> writes:

> Mark H Weaver <mhw@netris.org> writes:
>
>> Indeed, (local-eval '(set! x 5) <env>) is _not_ equivalent to
>> (module-set! (current-module) 'x 5).
>
> To clarify: I was thinking about
>
> (local-eval '(set! x 5) <env>) vs
> (local-eval '(module-set! (current-module) 'x 5) <env>)
>
>> Assuming that `x' is not locally bound within the captured lexical
>> environment, the first sets `x' in the module captured by
>> (the-environment), i.e. the module where `x' would have been set if you
>> had put (set! x 5) in place of (the-environment).  The second sets `x'
>> in the (current-module) at the time of evaluation.
>
> Yes, that would be what I would expect given the two local-eval calls
> above.

Let me check with my "reference hack" on Guilev1:

(define (my-eval form env)
  (call-with-current-continuation
   (lambda (x)
     (env (list x form)))))

(define-macro (my-env)
  (call-with-current-continuation identity))

(display
 (save-module-excursion
  (lambda ()
    (let ((env (my-env)))
      (set-current-module (resolve-module '(none)))
      (my-eval '(current-module) env)))))

=> #<directory (none) b786d380>

Even that agrees.  Not that I would be eager to analyze why.

-- 
David Kastrup