baconator.clj

(ns erdos-c.core
  [:require [yokogiri.core :refer :all]])

(def client (make-client :javascript false))

(defn page [uri]
  (get-page client (str "http://en.wikipedia.org" uri)))

(defn link-snippets [uri]
  (xpath (page uri) "//a"))

(defn links [uri]
  (->> uri
    (link-snippets)
    (map attrs)
    (map :href)
    (remove nil?)))

(defn wikifilter [uri] 
  (re-find #"\A\/wiki\/" uri))

(defn wiki-links [uri]
  (filter wikifilter (links uri)))

(defn search [start target]
  (loop [queue (conj (clojure.lang.PersistentQueue/EMPTY) (list start))
         visited #{}]
    (let [links (peek queue)
          test-link (first links)
          page-links (filter #(not (contains? visited %)) (wiki-links test-link))]
      (if (some #(= target %) page-links)
        links
        (recur (pop (apply conj queue (map #(cons % links) page-links)))
               (apply conj visited page-links))))))