Take the following code:
#+BEGIN_SRC racket
(require racket/match)
(define-syntax-rule (methods* [(method-name method-args ...) body ...] ...
fallback)
(let ((method-name
(lambda (method-args ...)
body ...)) ...)
(define all-methods (list (cons 'method-name method-name) ...))
(define method-dispatch
(make-keyword-procedure
(lambda (kw-args kw-vals method . args)
(match (assq method all-methods)
[(cons _name found-method)
found-method
#;(keyword-apply found-method kw-args kw-vals args)]
[#f
(keyword-apply fallback kw-args kw-vals method args)]))))
method-dispatch))
(define no-such-method
(make-keyword-procedure
(lambda (kw-vals kw-args method . args)
(error "No such method" method))))
(define-syntax-rule (methods method-defns ...)
(methods* method-defns ... no-such-method))
#+END_SRC
This is kind of a kluge, I know. But you get the idea. Let over
lambda, because we're going to be reusing these procedures over and over
again across multiple calls.
Now let's say I instantiate this like:
#+BEGIN_SRC racket
(define my-methods
(methods
[(double x)
(* x x)]))
#+END_SRC
> my-methods
#<procedure:...tor-lib/methods.rkt:130:7>
That's the line where method-dispatch is defined, *inside the macro*.
But what I really want is for the annotation on the procedure to be
*where my-methods is defined*.... not pointing back inside the macro.
I have no idea how to do this. Thoughts?
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