lexical_analyzer.l

%option noyywrap
%{
/*****************声明和选项设置  begin*****************/
#include <stdio.h>
#include <stdlib.h>

#include "syntax_tree.h"
#include "syntax_analyzer.h"

int lines=1;
int pos_start=1;
int pos_end=1;

void pass_node(char *text){
     yylval.node = new_syntax_tree_node(text);
}

/*****************声明和选项设置  end*****************/

%}

%x COMMENT

%%
 /* to do for students */
 /* two cases for you, pass_node will send flex's token to bison */
\+ 	{pos_start = pos_end; pos_end += 1; pass_node(yytext); return ADD;}
\-	{pos_start = pos_end; pos_end += 1; pass_node(yytext); return SUB;}
\*	{pos_start = pos_end; pos_end += 1; pass_node(yytext); return MUL;}
\/	{pos_start = pos_end; pos_end += 1; pass_node(yytext); return DIV;}
\<	{pos_start = pos_end; pos_end += 1; pass_node(yytext); return LT;}
\<=	{pos_start = pos_end; pos_end += 2; pass_node(yytext); return LTE;}
\>	{pos_start = pos_end; pos_end += 1; pass_node(yytext); return GT;}
\>=	{pos_start = pos_end; pos_end += 2; pass_node(yytext); return GTE;}
==	{pos_start = pos_end; pos_end += 2; pass_node(yytext); return EQ;}
!=	{pos_start = pos_end; pos_end += 2; pass_node(yytext); return NEQ;}
=	{pos_start = pos_end; pos_end += 1; pass_node(yytext); return ASSIN;}
;	{pos_start = pos_end; pos_end += 1; pass_node(yytext); return SEMICOLON;}
,	{pos_start = pos_end; pos_end += 1; pass_node(yytext); return COMMA;}
 /* TODO: phase1. 请在这里补充其他的词法规则 */


. { pos_start = pos_end; pos_end++; return ERROR; }

 /****请在此补全所有flex的模式与动作  end******/
%%