isaacs

# Hello, and welcome to makefile basics.
#
# You will learn why `make` is so great, and why, despite its "weird" syntax,
# it is actually a highly expressive, efficient, and powerful way to build
# programs.
#
# Once you're done here, go to
# http://www.gnu.org/software/make/manual/make.html
# to learn SOOOO much more.

swannodette

(defn validates-credentials [username password]
  (let [uc (count username)
        pc (count password)]
    (match [username uc password pc]
       [(:or nil "") _ _ _]         {:error "No username given" :field "name"}
       [_ _ (:or nil "") _]         {:error "No password given" :field "pass"}
       [_ (_ :guard #(< % 3)) _ _]  {:error "Username less than 3 characters" :field "pass"}
       [_ _ _ (_ :guard #(< % 4))]  {:error "Password less than 4 characters" :field "pass"}
       [#"^([a-z0-9-_]+)$" _ _ _]   {:error "Username contains invalid characters" :field "name"}
       :else true)))