这是一个training语言的词法分析程序，可以对输入的字符串流进行词法分析。（1）可以输入所给文法的源程序的字符串；（2）程序的输出形式为单词串的输出形式；（3）可以测试源程序片段 1.关键字：

function if then while do endfunc

2.专用符号：

= + - * / <<= != >>= == （） #

3.其它的单词是标示符（id）和整型常数(num)由下述正规式定义

id=letter(letter|digit)*

num=digit digit*

letter=a |...|z|A|....|Z

digit=0|...|9

-This is a training program language lexical analysis can be performed on the input string stream lexical analysis. (1) You can enter a string given the source of grammar　output form (2) procedures for the output in the form of word strings　(3) to test the source clip a keyword:. Function if then while do endfunc 2. special symbols: =+-*/< <　= = > >　===　()# 3 is another word identifier (id) and integer constants (num) is defined by the following regular id = letter (!. letter | digit)* num = digit digit* letter = a | ... | z | A | .... | Z digit = 0 | ... | 9