dsl_arithmetic_4_optimize-op.clj

(defn- make-op
  [rator rands]
  (if (< 1 (count rands))
    (into [rator] rands)
    (first rands)))

(defn- optimize-op
  [[rator & rands] binary-op neutral]
  (let [{csts true vars false} (group-by cst? rands)
        sum-cst (reduce binary-op neutral csts)]
    (cond
      (empty? vars) (cst sum-cst)
      (= neutral sum-cst) (make-op rator vars)
      :else (make-op rator (into [(cst sum-cst)] vars))
      )))