guia de criação de macros

macros.clj

;; escreva uma função que recebe o listas e simbolos como argumento,
;; e faca as transformacoes
(defn my-with-open-fn
  [bindings body]
  `(let ~bindings
     (try
       ~@body
       (finally
         ~@(for [v (map first (partition-all 2 bindings))]
             `(.close ~v))))))
;; teste usando listas e simbolos
(my-with-open-fn '[a (start!)]
  '((my-code on a)))
;; => (clojure.core/let [a (start!)] (try (my-code on a) (finally (.close a))))

;; parece correto!

;; crie a macro "de verdade"
(defmacro my-with-open [bindings & body]
  (my-with-open-fn bindings body))

;; verifique a macro "de verdade" usando macroexpand
(macroexpand '(my-with-open [hello (world)]
                (apply hello world)))