Implement motion and take commands

lambdaV.py

@@ -122,13 +122,54 @@ def condition_on_apple(inverted):
 
 # return value: "" or error message
 def command_step():
-    #TODO
+    if condition_in_front_of_wall(False):
+        return "You walked into a wall."
+
+    if condition_facing_north(False):
+        cursor_position[1] = cursor_position[1]-1
+    elif condition_facing_south(False):
+        cursor_position[1] = cursor_position[1]+1
+    elif condition_facing_east(False):
+        cursor_position[0] = cursor_position[0]+1
+    elif condition_facing_west(False):
+        cursor_position[0] = cursor_position[0]-1
+    else:
+        return "Cannot step because direction is unknown."
     return ""
 
 def command_left():
+    global cursor_current
+    if condition_facing_north(False):
+        cursor_current = cursor_west
+    elif condition_facing_south(False):
+        cursor_current = cursor_east
+    elif condition_facing_east(False):
+        cursor_current = cursor_north
+    elif condition_facing_west(False):
+        cursor_current = cursor_south
+    else:
+        return "Cannot turn left because direction is unknown."
     return ""
 
 def command_right():
+    global cursor_current
+    if condition_facing_north(False):
+        cursor_current = cursor_east
+    elif condition_facing_south(False):
+        cursor_current = cursor_west
+    elif condition_facing_east(False):
+        cursor_current = cursor_south
+    elif condition_facing_west(False):
+        cursor_current = cursor_north
+    else:
+        return "Cannot turn right because direction is unknown."
+    return ""
+
+def command_take():
+    if condition_on_apple(True):
+        # Note: condition is inverted
+        return "Cannot take apple, there is no apple here."
+    field[cursor_position[1]] = field[cursor_position[1]][:cursor_position[0]]+" "+field[cursor_position[1]][cursor_position[0]+1:]
     return ""
 
 def command_repeat(number, parsed_code):
@@ -137,9 +178,6 @@ def command_repeat(number, parsed_code):
 def command_while(parsed_condition, parsed_code):
     return ""
 
-def command_take():
-    return ""
-
 def command_if(parsed_condition, parsed_then_code, parsed_else_code):
     return ""