Implemented interpreter, almost fully documented

improved/parser_combinator.py

@@ -91,7 +91,7 @@ class Reserved(Parser):
 
             returns -- a Result object | None
         """
-        if pos < len(tokens) and tokens[pos] == [self.value, self.tag]:
+        if pos < len(tokens) and tokens[pos][0] == self.value and tokens[pos][1] is self.tag:
             return Result(tokens[pos][0], pos + 1)
         else:
             return None
@@ -170,7 +170,7 @@ class Alternate(Parser):
     def __call__(self, tokens, pos):
         """
             Calls the parser. Returns a result if either
-            parser matches, otherwisu returns None.
+            parser matches, otherwise returns None.
 
             tokens -- the token list
             pos    -- the position to check