get started step 4

step4.clj

;; add a value to the session
(defpage "/login" {}
         (session/put! :admin true)
         (layout
           [:p "Are you loggedin? "] 
           [:p (session/get :admin)]))

;; set a cookie and get its value
(defpage "/cookie" []
         (cookie/put! :noir "stuff")
         (let [v (cookie/get :noir)]
           (layout
             [:p "You created a cookie:"]
             [:p "Value " v])))

;; validate our math, if the first statement
;; is false, it fails validation and the error 
;; is added for the given key.
(defpage "/validate" []
         (vali/rule (= 3 3)
                    [:math "3 != 3"])
         (vali/rule (= 1 2)
                    [:math "1 != 2"])
         (layout
           [:p "Let's check your math: "]
           [:p (str (vali/get-errors :math))]))

for newbs, would help to define the proper the requires so the examples just work i.e. for the last example

(:require [noir.validation :as val])

I'd give you a pull request for the website but that's not really possible with gists