[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Scheme-reports] 6.1 Exceptions needs examples
* Aaron W. Hsu [2012-03-21 19:45] writes:
> I can share my thoughts on this one...
>
> On Wed, 2012-03-21 at 07:49 +0100, Helmut Eller wrote:
>> (let ((events '()))
>> (guard (c
>> (#t #f))
>> (guard (c
>> ((dynamic-wind
>> (lambda () (set! events (cons 'c events)))
>> (lambda () #f)
>> (lambda () (set! events (cons 'd events))))
>> #f))
>> (dynamic-wind
>> (lambda () (set! events (cons 'a events)))
>> (lambda () (raise 'error))
>> (lambda () (set! events (cons 'b events))))))
>> (reverse events))
>
> Let's keep in mind the text of the standard, which should match that of
> R6RS for this case, and therefore, we can test any Scheme implementation
> claiming to conform to R6RS to see if we get what we expect.
[...]
> This gives '(a b c d a b) as the only valid result.
Thanks, for clearing this up. That was also my interpretation of R6RS.
I'd like to note, that this example requires full continuations since a
and b occur two times in the event trace
Helmut
_______________________________________________
Scheme-reports mailing list
Scheme-reports@x
http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports