"R. Kent Dybvig" <dyb_at_cs.indiana.edu> writes:
>> > Okay, but where's the definition of parameterize in terms of your
>> > dynamic binding construct? It didn't make it into your note.
>>
>> I was assuming I'd use your definition unchanged.
>
> [...]
> I'm looking for proof of this claim, i.e., a definition of the parameter
> mechanism in terms of your dynamic-binding mechanism and thread-local
> storage. So far you've only offered up a definition of make-parameter
> that is independent of your dynamic-binding mechanism and no definition of
> parameterize.
I wrote:
>> I was assuming I'd use your definition unchanged.
But, to repeat, here's your definition:
(define-syntax parameterize
(lambda (x)
(syntax-case x ()
[(_ ((x v) ...) e1 e2 ...)
(with-syntax ([(p ...) (generate-temporaries #'(x ...))]
[(y ...) (generate-temporaries #'(x ...))])
#'(let ([p x] ... [y v] ...)
(let ([swap (lambda () (let ([t (p)]) (p y) (set! y t)) ...)])
(dynamic-wind #t swap (lambda () e1 e2 ...) swap))))])))
How does it fall down?
--
Cheers =8-} Mike
Friede, V?lkerverst?ndigung und ?berhaupt blabla
Received on Wed Feb 21 2007 - 12:42:59 UTC