rewrite execute usiung accumulate, add second test case

rover.fnl

@@ -43,11 +43,10 @@
            :l {:direction (turn-left rover.direction)}
            _ (assert false (. "unrecognised command " string)))))
 
-(fn execute [rover [cmd & cmds]]
-  (let [r1 (command rover cmd)]
-    (if (next cmds)
-        (execute r1 cmds)
-        r1)))
+(fn execute [rover cmds]
+  (accumulate [rover rover
+               _ c (ipairs cmds)]
+    (merge rover (command rover c))))
 
 (fn rover [x y direction]
   {: x
@@ -99,5 +98,10 @@
   (expect "Rotates to north when pointing west and asked to turn right"
           (execute r [:r]) {:x 2 :y 4 :direction :n}))
 
+(let [r (rover 1 1 :s)]
+  (expect "Multiple commands are executed in the right order"
+          (execute r [:l :l :f :f :f :r :f])
+          {:x 2 :y 4 :direction :e}))
+
 
 (print "OK")