Ordering columns

columns.clj

(def c-order
  (let [order [:id :title :author :date :price]]
    (zipmap order (range (count order)))))

(defn column-sort
  [k1 k2]
  (compare (get c-order k1 -1)
           (get c-order k2 -1)))

(def test-data
  (into (sorted-map-by column-sort)
        {:price "3.99" :author "John D." :title "A Sorted Map"
         :id 12345 :date (java.util.Date.)}))

user=> test-data
{:id 12345, :title "A Sorted Map", :author "John D.", :date #inst "2012-08-08T00:18:50.219-00:00", :price "3.99"}

user=> (vec test-data)
[[:id 12345] [:title "A Sorted Map"] [:author "John D."] [:date #inst "2012-08-08T00:18:50.219-00:00"] [:price "3.99"]]

zipmap can take a lazy-seq so you can just do (zipmap order (range))