What about passing the configuration data to `other-module-begin` via keyword arguments or tagged expressions in the body of the `(other-module-begin ...)` expansion? Is there a particular reason `mb` and `other-module-begin` need to communicate with syntax properties?
On Tuesday, November 28, 2017 at 7:15:50 PM UTC-8, Matthew Butterick wrote: > > I'm making a #%module-begin macro, but I want to delegate it to an > existing one. > > OK, let's start with a rename transformer: > > (provide (rename-out [mb #%module-begin])) > (define-syntax mb (make-rename-transformer #'other-module-begin)) > (define-syntax other-module-begin (λ (stx) #'foo)) > > That works, but I also need to pass some extra data to > `other-module-begin` that controls how it's configured during this > delegation. > > OK, let's add a syntax property. But wrapping the property around the > transformer doesn't work, because a rename transformer is not `syntax?`: > > (provide (rename-out [mb #%module-begin])) > (define-syntax mb (syntax-property (make-rename-transformer > #'other-module-begin) 'foo "bar")) > (define-syntax other-module-begin (λ (stx) #'foo)) > > ;; syntax-property: contract violation > > > I can wrap the property around the target identifier, but the syntax > property doesn't stick: > > (provide (rename-out [mb #%module-begin])) > (define-syntax mb (make-rename-transformer (syntax-property > #'other-module-begin 'foo "bar"))) > (define-syntax other-module-begin (λ (stx) #'foo)) > > (syntax-property #'mb 'foo) ; #f > > > Other possibilities with equivalent effect? -- 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]. For more options, visit https://groups.google.com/d/optout.
