DFS path finder

gistfile1.clj

(defn find-path
  [graph from to]
  ((fn this [graph from to path]
     (if (= from to)
       (println "Found it:" path)
       (let [children (for [v (graph from) :when (not (some #{v} path))] v)]
	 (if (empty? children)
	   (println "Dead end:" path)
	   (doseq [v children]
	     (this graph v to (conj path v)))))))
   graph from to [from]))

(def graph {:a [:b :c :g]
	    :b [:e :g]
	    :c []
	    :d []
	    :e [:a]
	    :f [:c :d]
	    :g [:e]})

(find-path graph :a :e)

;; Output:
;; Found it: [:a :b :e]
;; Found it: [:a :b :g :e]
;; Dead end: [:a :c]
;; Found it: [:a :g :e]