Is the issue simply that `begin`'s body is not an internal definition context, but instead spliced into the containing context?
Robby On Thu, Mar 7, 2019 at 12:01 AM Milo Turner <iital...@gmail.com> wrote: > > I was discussing with a friend some of the edge cases in how internal > definition contexts and expansion > work, when I accidentally ran into behavior that doesn't seem right. > > (let () > (foo) > (define-syntax-rule (define-it m) > (define-syntax (m stx) #'"hello!")) > (define-it foo)) > > ;; -> "hello!" > > (begin > (foo) > (define-syntax-rule (define-it m) > (define-syntax (m stx) #'"hello!")) > (define-it foo)) > > ;; application: not a procedure; > ;; expected a procedure that can be applied to arguments > ;; given: "hello!" > > Both cases are of course predicated on the behavior of > internal-definition-contexts passing over unbound > identifiers twice to see if they "became" a macro by the time the definition > context has been fully > populated. I know the semantics here are pretty quirky and up for debate, but > I don't think that this is > the expected behavior in any case. What seems to be happening precisely is > that when "foo" is expanded > in a local definition context, the parenthesis are given to the transformer > procedure (#'(foo)), versus if it is > expanded in a module begin context, only the identifier is given to the > transformer procedure (#'foo), and > then the parenthesis are added on afterwards. > > ;; if in local definition context: > (f . args) ==> (#%expression (f . args)) > ;; if in module begin context (BAD!): > (f . args) ==> ((#%expression f) . args) > > -- > 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.
