The main trick in this case is to recognize `define-values` (which is what `define` expands to) instead of `define`. That's because `define-values` propagates syntax arming to its identifiers and right-hand side, which means that your macro is allowed to pull it apart.
You'll also need to use an expansion context other than 'expression, though. At Thu, 16 Apr 2020 18:15:07 -0700 (PDT), Ryan Kramer wrote: > The following code produces '(1 2 3 4) > > (define-syntax (collect stx) > (syntax-case stx (define) > [(_ (define id val) rest ...) > #'(let ([id val]) > (collect rest ...))] > [(_ (macro arg ...) rest ...) > (syntax-local-value #'macro (lambda () #f)) > (let ([expanded (local-expand #'(macro arg ...) 'expression (list > #'define))]) > (println expanded) > #`(collect #,expanded rest ...))] > [(_ a rest ...) > #'(cons a (collect rest ...))] > [(_) > #'(list)])) > > (define-syntax-rule (my-define stuff ...) > (define stuff ...)) > > (collect 1 2 (define x 3) x 4) > > > I would like `(collect 1 2 (my-define x 3) x 4)` to produce the same > result. But instead I get the error message "let-values: cannot bind > tainted identifier in: x" > > "OK, maybe this is impossible" I thought, and moved on to what I should > have been working on anyway. But now I see that `class*` does seem to > recognize arbitrary macros. The following example shows that `class*` > seemingly understands my arbitrary `define-foo` macro: > > (define-syntax-rule (define-foo) > (define/public (foo) > (list this 'foo))) > > (define my-class% > (class* object% () > (super-new) > (define-foo))) > > (define c (new my-class%)) > (send c foo) > > How does `class*` understand my `define-foo` macro? And can the same > technique be used to fix my `collect` macro? > > -- > 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. > To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-users/0d01f4c1-f0b4-49cb-b9c2-fca7e2ca > 6429%40googlegroups.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 racket-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/5e991981.1c69fb81.4cebf.da91SMTPIN_ADDED_MISSING%40gmr-mx.google.com.
