quasi-quote-macro.clj

 (defmacro if-in-str [haystack & clauses]
   `(do
      ~@(map
          (fn [clause]
            (let [needle (first clause)
                  is-present-form (second clause)
                  is-not-present-form (nth clause 2 nil)]
              `(if (> (.indexOf ~haystack ~needle) -1)
                 ~is-present-form
                 ~is-not-present-form)))
          clauses)))