Alternate for http://blog.jayfields.com/2012/10/clojure-avoiding-anonymous-functions.html

gistfile1.txt

(def input [{:name "jay fields", :current-city "new york", :employer "drw.com"}
            {:name "john dydo", :current-city "new york", :employer "drw.com"}
            {:name "mike ward", :current-city "chicago", :employer "drw.com"}
            {:name "chris george", :current-city "new york", :employer "thoughtworks.com"}])

;; I have some more elegant impls of this but I didn't want to suck in my util lib
(defn mod-vals [f m]
  (reduce-kv (fn [r k v] (assoc r k (map f v)))
             {}
             m))

;; group, then modify the records
(mod-vals :name (group-by :employer input))