Make this a standalone application and add level file support

lambdaV.py

@@ -522,4 +522,58 @@ def debug_setup():
     setup_and_run_task(empty_field, [1,1], cursor_east, "Debug mode", ["step", "left", "right", "take", "repeat", "while", "if"], ["facing north", "facing south", "facing east", "facing west", "in front of wall", "goal reached", "on apple"])
 
 if __name__ == "__main__":
-    pass
+    import sys, os, json
+
+    level = 0
+    single_file_mode = False
+    level_file_name = ""
+
+    def wrong_usage():
+        print("Usage:\n  " + sys.argv[0] + " [l<number> | level_file_name.json]\n\n- Run without arguments to start at level 0.\n- Run with a single argument made of 'l' and a number to start at that level.\n- Run with a file name to start that specific level.")
+        sys.exit(1)
+
+    if len(sys.argv)>1:
+        if len(sys.argv)>2:
+            wrong_usage()
+        if sys.argv[1][0]=="l":
+            try:
+                level=int(sys.argv[1][1:])
+            except:
+                if os.path.isfile(sys.argv[1]):
+                    level_file_name = sys.argv[1]
+                    single_file_mode = True
+                else:
+                    wrong_usage()
+        elif os.path.isfile(sys.argv[1]):
+            level_file_name = sys.argv[1]
+            single_file_mode = True
+        else:
+            wrong_usage()
+
+    if not single_file_mode:
+        level_file_name = os.path.join("levels", str(level)+".json")
+
+    while os.path.isfile(level_file_name):
+        level_file = open(level_file_name, "r")
+        level_raw = level_file.read()
+        level_file.close()
+        level_data = json.loads(level_raw)
+
+        cursor_start = ""
+        if level_data["start heading"]=="north":
+            cursor_start = cursor_north
+        elif level_data["start heading"]=="south":
+            cursor_start = cursor_south
+        elif level_data["start heading"]=="east":
+            cursor_start = cursor_east
+        elif level_data["start heading"]=="west":
+            cursor_start = cursor_west
+        else:
+            print("Unknown start heading!")
+            sys.exit(1)
+        setup_and_run_task(level_data["field"], level_data["start position"], cursor_start, level_data["text"], level_data["allowed commands"], level_data["allowed conditions"])
+
+        if single_file_mode:
+            break
+        level+=1
+        level_file_name = os.path.join("levels", str(level)+".json")