%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;
int pos_start;
int pos_end;

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

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

%}


%%
 /* 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++; return ERROR; }

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