I agree that this is a bug --- specific to impersonators that are not chaperones --- and I've pushed a repair to the Git repo.
The general repair was to make impersonator-property predicates and accessors sensitive to `prop:impersonator-of`. When a structure impersoator does not have a particular impersonator property, but its structure has the `prop:impersonator-of` property, then the structure produced by `prop:impersonator-of` is checked (recursively). That change fixes the problem with keyword procedures, because `impersonator-procedure` on keyword-acepting procedure is implemented through an internal structure type that has `prop:impersonator-of`. Thanks for the report! At Fri, 6 Mar 2015 20:04:10 -0500, Scott Moore wrote: > Hi, > > I've run into some strange behavior with the interaction between > impersonators and make-keyword-procedure. I expect that when not invoked > with keywords, the result of make-keyword-procedure and a lambda with the > same form should be equivalent. Instead, they behave differently when > impersonated. I have included a small module that demonstrates the issue > below. I expect that the two checks at the bottom should succeed. > > Thanks, > Scott > > #lang racket > > (require rackunit) > > (define-values (prop:my-prop my-prop? my-prop-accessor) > (make-impersonator-property 'my-prop)) > > (define (mark-with-my-prop val) > (impersonate-procedure > val > #f > prop:my-prop > #t)) > > (define (mark-fun-mkp f) > (mark-with-my-prop > (make-keyword-procedure > (λ (kwds kwd-args . other-args) > (keyword-apply f kwds kwd-args other-args)) > (λ args > (apply f args))))) > > (define (mark-fun-lambda f) > (mark-with-my-prop > (λ args > (apply f args)))) > > (define (dummy-impersonator val) > (make-keyword-procedure > (λ (kwds kwd-args . other-args) > (apply values kwd-args other-args)) > (λ args > (apply values args)))) > > (define marked-mkp (mark-fun-mkp display)) > (define marked-lambda (mark-fun-lambda display)) > > (check-eq? (my-prop? marked-lambda) (my-prop? marked-mkp)) > (check-eq? (my-prop? (impersonate-procedure marked-lambda > (dummy-impersonator marked-lambda))) > (my-prop? (impersonate-procedure marked-mkp (dummy-impersonator > marked-mkp)))) > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
