same.clj

(defn- same-dispatch [& args]
  (class (last args)))

(defmulti
  #^{:doc
     "same is a mutlimethod that is designed to \"undo\" seq.
It expects a seq-fn that returns a normal seq, and the 
appropraite args.  It converts the resulting seq into the same
type as the last argument.  If it is a sorted seq, the 
comparator is preserved.  

This operation is fundamentally eager, unless a 
clojure.lang.LazySeq is presented.  In this case laziness is
preserved, as it is not possible to infer the original data
type."
     :arglists '([seq-fn & args])}
  same same-dispatch)

(defmethod same String
  [hof & args]
  (apply str (apply hof f args)))

(defmethod same clojure.lang.LazySeq
  [hof & args]
  (apply hof args))

(defmethod same :default
  [hof & args]
  (into (empty (last args)) (apply hof args)))