deterpolate

deterpolate.clj

(defn deterpolate [s]
  (loop [tokens   (interpolate s)
         out-str  (StringBuffer.)
         out-args []]
    (if (seq tokens)
      (let [token (first tokens)]
        (cond (string? token)
              (recur (rest tokens)
                     (doto out-str (.append token))
                     out-args)
              (vector? token)
              (recur (rest tokens)
                     (doto out-str (.append (str/join "," (map (constantly "?") token))))
                     (into out-args token))
              :else
              (recur (rest tokens)
                     (doto out-str (.append "?"))
                     (conj out-args token))))
      (into [(str out-str)] out-args))))

user=> (deterpolate "select * from foo where x < ~{x} and y in (~{[a,b,3]})")
["select * from foo where x < ? and y in (?,?,?)" x a b 3]

@alandipert a useful addition might be to support use cases like:

(let [ids [1 2 3 4 5]]
  (deterpolate "SELECT * FROM foo WHERE id IN (~{ids})"))