(defmacro cond-let
  ([] nil)
  ([x] (throw (IllegalArgumentException. "cond-let error: last one form")))
  ([a b] (list 'if a b nil))
  ([a b c & forms]
   (if (vector? a)
     (list 'let a   (list 'if b c (cons 'cond-let forms)))
     (list 'if  a b (cons 'cond-let (cons c forms)))
     )))
 
(defn tst [m]
  (cond-let
    [a (:a m)]
    (not a) "not a"
    [b (+ 1 a)
     c (* 10 b)]
    (< c 50) "too small c"
    (= c 50) "exact c"
    [d (str "a = " a ", b = " b ", c = " c)
     e (count d)]
    :else {:text d, :length e}))
 
(println (tst {}))
(doseq [x '(1 4 5)] (println (tst {:a x})))
 

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