separate turn-left and turn-right functions

rover.fnl

@@ -13,22 +13,23 @@
                               :actual actual#
                               })))))
 
-(fn rotate [direction rotation]
-  (let [chooser
-        (match rotation
-          :r {
-              :n :e
-              :e :s
-              :s :w
-              :w :n
-              }
-          :l {
-              :n :w
-              :w :s
-              :s :e
-              :e :n
-              })]
-    (. chooser direction)))
+(fn turn-left [direction]
+  (-> {
+       :n :w
+       :w :s
+       :s :e
+       :e :n
+       }
+      (. direction)))
+
+(fn turn-right [direction]
+  (-> {
+       :n :e
+       :e :s
+       :s :w
+       :w :n
+       }
+      (. direction)))
 
 
 (fn command [rover string]
@@ -38,8 +39,8 @@
          :s (merge rover {:y (- rover.y 1)})
          :w (merge rover {:x (- rover.x 1)})
          :e (merge rover {:x (+ rover.x 1)}))
-    :r (merge rover {:direction (rotate rover.direction :r)})
-    :l (merge rover {:direction (rotate rover.direction :l)})
+    :r (merge rover {:direction (turn-right rover.direction)})
+    :l (merge rover {:direction (turn-left rover.direction)})
     _ (assert false (. "unrecognised command " string))))
 
 (fn execute [rover [cmd & cmds]]