词法分析程序的功能

输入：源程序

输出：二元组（词法记号,属性值/其在符号表中的位置）构成的序列。



例如：对源程序

x:=5 if (x>0) then x:=2*x+1/3 else x:=2/x #

经词法分析后输出如下序列：

（10,’x’）(18, :=) (11,5) (26, ) (2, if ) (27,( )-Function of lexical analysis program input: source output: pair (lexical mark, property value/its position in the symbol table) constitute the sequence. For example: on the source x: = 5　if (x>　0) then x: = 2* x+1/3　else x: = 2/x # The lexical analysis of the output sequence is as follows: (10, ' x ' ) (18,: =) (11,5) (26, ) (2, if) (27, () ... ...