moves forward southwards

rover.fnl

@@ -12,7 +12,9 @@
                          })))))
 
 (fn command [rover commands]
-  {:x 0 :y 1 :direction :n})
+  (match rover.direction
+    :n {:x 0 :y (+ rover.y 1) :direction :n}
+    :s {:x 0 :y (- rover.y 1) :direction :s}))
 
 (fn rover [x y direction]
   {: x
@@ -38,5 +40,11 @@
    (r:command [:f])
    {:x 0 :y 1 :direction :n}))
 
+(let [r (rover 0 0 :s)]
+  (expect
+   "Moves south when pointing south and asked to move forward"
+   (r:command [:f])
+   {:x 0 :y -1 :direction :s}))
+
 
 (print "OK")