when-lets.clj

(defmacro when-lets [[symbol value & more :as bindings] & body]
  (if (not-empty bindings)
    `(let [tmp# ~value] (when tmp# (let [~symbol tmp#] (when-lets [~@more] ~@body))))
    `(do ~@body)))


(defmacro when-lets [bindings & body]
  (assert (vector? bindings))
  (assert (even? (count bindings)))
  (if (not-empty bindings)
    (let [[symbol value & more] bindings]
      `(when-let [~symbol ~value] (when-lets [~@more] ~@body)))
    `(do ~@body)))