(define-syntax define-method
  (ir-macro-transformer
   (lambda (expr inject compare)
     (assert (pair? expr))
     (let* ((proc (car expr))
            (defn (cdr expr))
            (_ (assert (list? defn)))
            (_ (assert (= 4 (length defn))))
            (sig     (first defn))
            (name    (car sig))
            (uri/req (second defn))
            (writer  (third defn))
            (args    (if writer
                         `(body #!key . ,(cdr sig))
                         `(#!key . ,(cdr sig))))
            (reader  (fourth defn)))
       (list 'quote
             `(define ,name
                (let* ((writer  ,writer) ; ensure this is eval'd only once
                       (uri/req ,uri/req) ; ensure this is eval'd only once
                       (uri    (cond ((request? uri/req) (request-uri uri/req))
                                     ((uri? uri/req) uri/req)
                                     (else (uri-reference uri/req))))
                       (method (cond ((request? uri/req) (request-method uri/req))
                                     (writer 'POST)
                                     (else 'GET))))
                  (lambda ,args
                    (let ((writer (if (writer) (writer body) #f))
                          (req (make-request uri: uri method: method)) ; poke the args into query string.
                          )
                      (call-with-input-request req writer ,reader))))))))))