def tokentype(self, s):
        """Parses string and returns a (Tokenizer.TYPE, value) tuple."""
        a = s[0] if len(s)>0 else ""
        b = s[1] if len(s)>1 else ""

        if a.isdigit() or (a in ["+","-"] and b.isdigit()):
            return self.parse_number(s)
        elif a == '"': return self.parse_string(s)
        elif a == ':': return self.parse_colon(s)
        elif a == ';': return self.parse_semicolon(s)
        else:
            return self.parse_word(s)