;; note- path-pattern should escape any regex patterns first, but doesn't.

(defn index-map [path-pattern]
  "Takes a path \"/foo/:bar/:what\" and returns the indices into the regex #\"/foo/([^/]*)/([^/]*)\""
  (zipmap (iterate inc 1)
          (map (comp keyword clojure.string/join rest)
               (filter #(re-matches #"^:.*" %)
                       (clojure.string/split path-pattern #"/")))))

(defn to-regex [path-pattern]
  "Takes a path \"/foo/:bar/:what\" and returns the regex #\"/foo/([^/]*)/([^/]*)\""
  (re-pattern
    (clojure.string/join (interpose \/ (map #(if (re-matches #"^:.*" %) "([^/]*)" %)
                                            (clojure.string/split path-pattern #"/"))))))

(defn matcher [path-pattern]
  "Takes a simple route pattern, such as /foo/:bar/:baz, and returns a string matching function that, if it's argument matches
returns a map with the named parameters"
  (let [re (to-regex path-pattern)
        imap (index-map path-pattern)]
    (fn [str]
      (if-let [matches (re-matches re str)]
        (apply hash-map (mapcat (fn [x] [(second x) (get matches (first x))]) imap))))))