Yes, it looks like the original cache is just re-installed when re-enabled.
Perhaps there should be an operation provided by Redex to clear away the cache. David On Wed, Mar 14, 2018 at 2:17 PM, 'Leandro Facchinetti' via Racket Users < [email protected]> wrote: > > First, thanks for the reply. Itβs valuable to have the author of the paper > from where I draw my example chime in π > > 1) Instead of turning the cache off completely, you could just > > invalidate the cache when the parameter changes, i.e. write a `set-k!' > > function that updates the parameter and toggles the cache off and back > on (I assume this will clear it out). > > > I believe the following program proves your assumption wrong: > > * * * > > #lang racket/base > > (require redex/reduction-semantics racket/list) > > (define k (make-parameter 0)) > > (define-language L > [e ::= any] > [t ::= [e ...]]) > > (define-metafunction L > tick : e _ _ _ t -> t > [(tick e _ _ _ t) ,(take (cons (term e) (term t)) (k))]) > > (term (tick a _ _ _ [])) ;; => '() > (parameterize* ([k 1] > [caching-enabled? #f] > [caching-enabled? #t]) > (term (tick b _ _ _ []))) ;; => '(b) > (parameterize ([k 1] > [caching-enabled? #f] > [caching-enabled? #t]) > (term (tick a _ _ _ []))) ;; => '() > > * * * > > If the cache was flushed, then weβd see β'(a)β instead of β'()β in the > last term. > > As I pointed out in my original message: cache invalidation continues to > be one of the *hard problems* in computer science. > > 3) Move the escaping ellipses to the outermost `begin' form. This > > allows you to write the escape once instead of for each Redex ellipse. > > It also means the code within the macro definition looks more like the > original. > > > That is one step in the right direction. Thanks for the suggestion. But I > still think macro-defined models are not the right abstraction here. > > -- > Leandro Facchinetti <[email protected]> > https://www.leafac.com > > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
