Clojure parser for SimpleCart(js) form POST/GET

simplecart_parser.clj

(ns webstore.simplecart_parser
  (:require [clojure.string :as string]))
  
;; see github.com/sventech/simplecart-js for tax calculation improvement fork
(def input-params 
  {"item_quantity_1" "1",
   "itemCount" "2",
   "item_price_1" "9.99",
   "store_name" "Online Store",
   "item_name_1" "Awesome Product - MP3",
   "currency" "USD",
   "taxCountry" "US",
   "return" "/success",
   "item_quantity_2" "1",
   "invoiceNumber" "ABC-123456789",
   "item_options_1" "artist: Family Band, number: ZH15862-MP3, physical: 0, weight: 0",
   "taxRate" "0.07",
   "cart_id" "12345",
   "item_name_2" "Excellent Title - CD",
   "taxRegion" "North Carolina",
   "item_price_2" "9.99",
   "item_options_2" "artist: New Band, number: XT13232-CD, physical: 1, weight: 0.3",
   "shipping" "0",
   "tax" "0",
   "cancel_return" "/cancel"})
   
;; shopping cart handling -- special thanks to Sean Omlor of Asheville Coder's league
 
(def cart-keys [:taxRegion :taxCountry :taxRate :tax :cart_id :itemCount 
                :currency :store_name :shipping :invoiceNumber])
 
(def item-keys
  [:item_name :item_options :item_quantity :item_price])
 
(defn one-to-n [n]
  (map inc (take n (range))))
 
(defn clean-key [key]
  (keyword (clojure.string/replace (name key) #"_\d+" "")))
 
(defn keys-for-num [item-num]
  (map #(keyword (str (name %) "_" item-num)) item-keys))
 
(defn num-items [items]
  (Integer/parseInt (:itemCount items)))
 
 
;; convert "artist: New Band, number: XT13232-CD, physical: 1, weight: 0"
;; into   {:item_artist "New Band", :item_number "XT13232-CD", :item_physical "1", :item_weight "0"}
(defn parse-options
  "Convert 'options' entry into multiple entries for item"
  [option-string]
  (let [option-list (string/split option-string #", ")]
    (let [option-seq (map #(string/split % #": ") option-list)]
      (into {} 
        (for [[k v] option-seq] 
          [(keyword (str "item_" k)) v])))))
 
(defn parse-items [item-map]
  "Break items by key like ':item_foo_1' into vector of maps"
  (into []
    (map #(merge % (parse-options (:item_options %)))
      (for [item-num (one-to-n (num-items item-map))]
        (reduce-kv (fn [m k v] (assoc m (clean-key k) v)) {}
          (select-keys item-map (keys-for-num item-num)))))))
 
;; keywordize string map, then separate cart-global keys from items
(defn parse-cart
  "Get clean map from shopping cart param POST"
  [param-map]
  (let [in-map (clojure.walk/keywordize-keys param-map)]
    (assoc (select-keys in-map cart-keys) 
            :items (parse-items in-map))))

Thank You, Much appreciated