rlm@0: (ns coderloop.reverse-seq
rlm@0:   (:use [clojure.contrib
rlm@0: 	 [duck-streams :only [file-str read-lines]]
rlm@0: 	 [str-utils :only [re-split]]])
rlm@0:   (:use rlm.shell-inspect)
rlm@0:   (:use [clojure [string :only [trim]]]))
rlm@0: 
rlm@0: (def c (file-str "/home/r/coderloop-test/reversesequence-c.in"))
rlm@0: (def a (file-str "/home/r/coderloop-test/reversesequence-a.in"))
rlm@0: (def b (file-str "/home/r/coderloop-test/reversesequence-b.in"))
rlm@0: 
rlm@0: (defn test-trace-map []
rlm@0:   (= [:a :b :c :d :e]
rlm@0:        (trace-map {:a :b :d :e :c :d :b :c})))
rlm@0: 
rlm@0: 
rlm@0: (defn read-name-map
rlm@0:   "takes a file of pairs of names and returns a map from the first
rlm@0:    element in those pairs to the second element in the pairs."   
rlm@0:   [#^java.io.File file]
rlm@0:   (let [pairs  (map #(re-split #"\W+" (trim %)) (read-lines file))]
rlm@0:     (zipmap (map first pairs) (map second pairs))))
rlm@0: 
rlm@0: (defn start-linked-map
rlm@0:   "takes a map-representing-a-list and finds the beginning of that list"
rlm@0:   [m]
rlm@0:   (first (remove (set (vals m)) (keys m))))
rlm@0: 
rlm@0: (defn trace-map
rlm@0:   "chains through a map-representing-a-list, building a list along the way."
rlm@0:   [m]
rlm@0:   (loop [index (start-linked-map m)
rlm@0: 	 chain (vector index)]
rlm@0:     (let [new-index (get m index ::sentinel)]
rlm@0:       (if (= new-index ::sentinel)
rlm@0: 	chain
rlm@0: 	(recur  new-index (conj chain new-index))))))
rlm@0: 
rlm@0: 
rlm@0: 
rlm@0: (if (command-line?)
rlm@0:   (dorun
rlm@0:    (map println (reverse (trace-map (read-name-map (file-str (first *command-line-args*))))))))