gistfile1.clj

(use 'syntactic-closure.core)

(define-syntax aif
  (sc-macro-transformer
    (fn [[_ test then else] env]
      (quasiquote
        (let [it ~(make-syntactic-closure env nil test)]
          (if it
            ~(make-syntactic-closure env '[it] then)
            ~(make-syntactic-closure env nil else)))))))

(define-syntax awhen
  (sc-macro-transformer
    (fn [[_ test & body] env]
      (quasiquote
        (aif ~(make-syntactic-closure env nil test)
          (do ~@(map #(make-syntactic-closure env '[it] %) body))
          nil)))))

(def m {:x "42"})

(aif (:x m)
  (Integer/parseInt it)
  0)

(awhen (:x m)
  (println "found x")
  (println it))

(macroexpand
  '(awhen (:x m)
     (println "found x")
     (println it)))
;=>
(let* [it465 (:x user/m)]
  (if it465
    (do
      (clojure.core/println "found x")
      (clojure.core/println it465))
    nil))