(defmulti apply-expression
  (fn [expr c]
    (if (coll? c)
      :coll
      :default)))

(defmethod apply-expression :coll
  [expr c]
  "stub")

(defmethod apply-expression :default
  [expr c]
  (let [% (read-string c)]
    (eval (read-string expr))))

(apply-expression "(+ % 1)" "1")