At Mon, 23 Mar 2020 01:45:40 -0700 (PDT), Yongming Shen wrote: > I tried the example you gave for my first question and it resulted in an > error.
Oops --- you're right. I lost track of what we try to make work at the top level. > I think this is because `(define-values (x) ...)` expands `...` without the > top-level-bind-scope, even when expand-context-to-parsed? is #t (according > to expander/expand/top.rkt). Is this a bug? Since the behavior goes far back, I think this is the behavior that we decided to settle for. > Related to your answer to my second question, `define-syntaxes` similarly > does not add the top-level-bind-scope when expanding `...`. Does this mean > that even for `define-syntaxes`, `...` won't use the top-level-bind-scope > binding(s) after all? The way that evaluation, binding, and expansion are interleaved means that a `define-syntaxes` macro can refer to itself in expansions. The binding of an identifier in a macro template is resolved after the macro is applied. The difference with `define` is that the right-hand side is expanded/compiled before `define` binds. > A little bit off-topic, in the definition of define-values (in > expander/expand/top.rkt), there is `(define-match m s ...)`, but for > define-syntaxes it is `(define-match m disarmed-s ...)`. Is this difference > significant? Or does define-match not care whether `s` or `disarmed-s` is > used? Using `disarmed-s` in the definition of `define-values` is probably a better idea, and I'll look into that more. It think it turns out not to matter, normally, because `define-values` is transparent to syntax arming via `syntax-arm` with a #t second argument (which is what the expander does). But it would be better to not rely on that. -- 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]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/5e78c215.1c69fb81.5b855.0569SMTPIN_ADDED_MISSING%40gmr-mx.google.com.
