Added command module.

command.py

@@ -0,0 +1,43 @@
+WHITESPACES = [' ', '\t', '\n']
+
+class Command:
+    command_prefix = '$'
+    __callbacks = {}
+
+    @staticmethod
+    def __getWords(string):
+        words = []
+        # Add whitespace to accept last word
+        string += " "
+        word = ""
+        for c in string:
+            if c in WHITESPACES and len(word) > 0:
+                words.append(word)
+                word = ""
+            elif c not in WHITESPACES:
+                word = word + c
+        return words
+
+    @staticmethod
+    def __getCommand(string):
+        words = Command.__getWords(string);
+        if words[0].startswith(Command.command_prefix):
+            return words[0][1:]
+        return ""
+
+    @staticmethod
+    def __getArgs(string):
+        words = Command.__getWords(string);
+        return words[1:]
+
+    @staticmethod
+    def registerCallback(command, callback):
+        Command.__callbacks[command] = callback
+
+    @staticmethod
+    def call(command):
+        func = Command.__callbacks.get(Command.__getCommand(command), None)
+        if func is not None:
+            return func(*tuple(Command.__getArgs(command)))
+        return None
+