> I've been trying to answer it, but having one of those humbling > experiences where I wonder how much I've really learned about macros, > after all. I distilled it to just: > > #lang racket > (define-syntax (define-modularize stx) > (syntax-case stx () > ([_ thing-name mod-name] > #'(begin > (module mod-name racket > (define thing-name #t) > (provide thing-name)) > (require 'mod-name))))) > > (define-modularize foo foo-mod) > ;; (require 'foo-mod) > foo ;; => foo: unbound identifier in module
I've struggled with this before as well. For this example, if I understand the docs correctly, the scope of the require-spec has to match the scope of the use. http://docs.racket-lang.org/reference/syntax-model.html?#(part._macro-introduced-bindings) "In require for other require-specs, the generator of the require-spec determines the scope of the bindings" So the code below would work. Is there a better way? #lang racket (define-syntax (define-modularize stx) (syntax-case stx () ([_ thing-name mod-name] (with-syntax ([require-spec (datum->syntax stx `(quote ,(syntax->datum #'mod-name)))]) #'(begin (module mod-name racket (define thing-name #t) (provide thing-name)) (require require-spec)))))) (define-modularize foo foo-mod) ;; (require 'foo-mod) foo ;; => foo: unbound identifier in module > > Only if the previous line with the require is uncommented, does it > work. IOW the module and thing define/provide seem just fine, it's the > require that is not working. Why? > > I've thought about it, used the stepper in DrRacket, tried everything > I can think of -- but can't get it to work. > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
