基本的词法分析器，用于Tiny语言的。实现了最基本的多个TOKEN,满足了上课和实验的要求。-Basic lexical analyzer for Tiny language. To achieve the most basic multiple TOKEN, to meet the classes and experiments.

输入：所给文法的源程序字符串。 输出：二元组（syn，token或sum）构成的序列。-Input: the source string grammar. Output: two tuple (syn, token or sum) of the sequence.