Multiply with infix notation in Clojure

infix-macro.clj

(defn pem-helper [sq symb]
  (loop [tail sq i 0]
    (if (seq tail)
      (if (= (first tail) symb)
        i
        (recur (rest tail) (inc i)))
      nil)))

(defn pem-mult-i [sq]
  (pem-helper sq '*))

(defn pem-div-i [sq]
  (pem-helper sq '/))

(defn pem-add-i [sq]
  (pem-helper sq '+))

(defn pem-minus-i [sq]
  (pem-helper sq '-))

(defn pemdas-i [sq]
  (cond 
    (some #(= % '*) sq) (pem-mult-i sq)
    (some #(= % '/) sq) (pem-div-i sq)
    (some #(= % '+) sq) (pem-add-i sq)
    (some #(= % '-) sq) (pem-minus-i sq)
    :else nil))

(defn bunch [sq i]
  (let [fir   (take (dec i) sq)
        bunch (list (nth sq i) (nth sq (dec i)) (nth sq (inc i)))
        rema  (drop (inc (inc i)) sq)]
    (concat (concat fir (list bunch)) rema)))

(defmacro my-infix [infix]
  (loop [cur infix]
    (let [i (pemdas-i cur)]
      (if i
        (recur (bunch cur i))
        (first cur)))))