This role of marks has been taken over by macro-introduction scopes, so that's still the explanation. A macro-introduction scope is added to the right places by first adding it everywhere to the argument to a macro transformer, then flipping it everywhere in the transformer's result.
(The documentation of `syntax-original?` includes an attempt to specify that, but none of the documentation is clear enough yet about scopes.) At Tue, 27 Oct 2015 04:31:57 -0500, Robby Findler wrote: > syntax-original? is querying a private property and that property > isn't set on the syntax object argument given to the transformer. (I > would have said because of the extra mark that's put on the argument, > but that's not happening now, but we get the same behavior anyway.) > > If you call syntax-local-introduce, you'll see the expected printouts: > > #lang racket > (define-syntax (print-original stx) > (syntax-case stx () > [(_ datum) > (begin > (displayln (syntax-original? (syntax-local-introduce #'datum))) > #'#'datum)])) > > (syntax-original? (print-original 'foo)) > > Robby > > > On Tue, Oct 27, 2015 at 1:56 AM, Alexis King <lexi.lam...@gmail.com> wrote: > > I wrote a simple program that determines whether a piece of syntax is > original in two different ways: > > > > (define-syntax (print-original stx) > > (syntax-case stx () > > [(_ datum) > > (begin > > (displayln (syntax-original? #'datum)) > > #'#'datum)])) > > > > (syntax-original? (print-original 'foo)) > > > > Running it prints #f, then #t. This seems to imply that #'datum is not > considered syntax-original? within the syntax transformer, but in the > expansion, it is. Stepping though the expression within the macro stepper, > the > identifier always seems to be considered original, so I would expect both > cases to be #t. > > > > Why is the result of syntax-original? different within the two contexts? If > this is the intended behavior, could it maybe be explained in the > documentation? > > > > Thanks, > > Alexis > > > > -- > > 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 racket-users+unsubscr...@googlegroups.com. > > 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 racket-users+unsubscr...@googlegroups.com. > 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 racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
