gistfile1.clj

(defmacro using "ns can be either a symbol designating a namespace, or
  a list like (ns :only [a b c])."
  [ns & body]
  (let [[ns vars] (if (sequential? ns)
                    [(first ns) (nth ns 2)] ;; skip the :only
                    [ns (keys (ns-publics (find-ns ns)))])]
    `(symbol-macrolet [~@(for [var vars,
                               clause [var `(quote ~(symbol (name ns) (name var)))]]
                           clause)]
        ~@body)))

user> (using [clojure.set :only [rename-keys]]
             (rename-keys {:a 1} {:a :b}))
{:a :b}

user> (using clojure.set
             (rename-keys {:a 1} {:a :b}))
{:a :b}