Depth-first search in clojurescript

dfs.cljs

#!/usr/bin/env planck

;; note: I haven't included any lein or boot tooling since there are no
;; dependencies. the easiest way to run is to use planck on osx, as a script.
;; can also be easily adapted to normal clojure or have some tooling added if you want to 
;; run it and don't have a mac

(ns dfs.core
"depth-first search of tree. Makes a few assumptions for simplification purposes: 
  1.  tree is directed graph 
  2.  stored in map in form 
  {:node [:child-node1 :child-node2 etc.]}. 
  3.  Assumes no cycles 
  4.  searches from 'right' qua end of node vector. 
  5.  Assumes that root node is known (search won't begin at nonexistent node)
  6.  Based on 5, represents singleton tree as empty map. (so (dfs {} :a :a) returns a match ")

(defn push [stack new-items]
  (if (= new-items nil)
    stack
   (into [] (concat stack new-items)))) 

(defn inner-dfs [stack tree start-node target-node]
  (let [children (get tree start-node)
        new-stack (push stack children)]
    (cond 
      (= start-node target-node) target-node
      (empty? new-stack) nil
     :else
      (recur (pop new-stack) tree (peek new-stack) target-node))))

(def dfs (partial inner-dfs []))

;; example: 
(def example-tree {:a [:b :c] :b [:d :e :f] :c [:g] :g [:h]})
(println (dfs example-tree :a :g))