Example of using a macro to rewrite defn in Clojure

my-defn.clj

(ns homoiconic.my-defn)

; ----------- --- --- -- -- - -

(defn hello [what]
  (str "hello " what))

(hello "world")

; ----------- --- --- -- -- - -

(defmacro my-defn [form args name]
  `(defn ~name ~args ~form))

(my-defn
  (str "HELLO " what)
  [what] my-hello)

(my-hello "world")