lex.l

%{
#include "parser.tab.h"
#include "string.h"
#include "def.h"
int yycolumn=1;
#define YY_USER_ACTION    	yylloc.first_line=yylloc.last_line=yylineno; \
	yylloc.first_column=yycolumn;	yylloc.last_column=yycolumn+yyleng-1; yycolumn+=yyleng;
typedef union {
	char type_char;
	int type_int;
	float type_float;
	char type_id[32];
	struct node *ptr;
} YYLVAL;
#define YYSTYPE YYLVAL

%}
%option yylineno

id   	[A-Za-z][A-Za-z0-9]*  
int    	[0-9]+
float  	([0-9]*\.[0-9]+)|([0-9]+\.)
char 	\'[^\n]\'

%%
{int}       {yylval.type_int=atoi(yytext);return INT;}
{float}     {yylval.type_float=atof(yytext);return FLOAT;}
{char}	    {yylval.type_char=yytext[1];return CHAR;}
"int"       {strcpy(yylval.type_id,  yytext);return TYPE;}
"float"     {strcpy(yylval.type_id,  yytext);return TYPE;}
"char"      {strcpy(yylval.type_id,  yytext);return TYPE;}

"return"    {return RETURN;}
"if"        {return IF;}
"else"      {return ELSE;}
"while"     {return WHILE;}
"for"	    {return FOR;}
"break"     {return BREAK;}
"continue"  {return CONTINUE;}

{id}       	{strcpy(yylval.type_id,  yytext);return ID;}/*由于关键字的形式也符合表示符的规则，所以把关键字的处理全部放在标识符的前面，优先识别*/
"//"[^\n]* 	{}
"/*"([^\*^\/]*|[\*^\/*]*|[^\**\/]*)*"*/" {}

";"		{return SEMI;}
","		{return COMMA;}
">"|"<"|">="|"<="|"=="|"!=" {strcpy(yylval.type_id, yytext);return RELOP;}

"+="		{return PLUSEQ;}
"-="		{return MINUSEQ;}
"*="		{return STAREQ;}
"/=" 		{return DIVEQ;}

"++"		{return INC;}
"--"		{return DEC;}
"="		{return ASSIGNOP;}
"+"		{return PLUS;}
"-"		{return MINUS;}
"*"		{return STAR;}
"/"		{return DIV;}
"&&"            {return AND;}
"||"            {return OR;}
"!"		{return NOT;}
"("		{return LP;}
")"		{return RP;}
"{"		{return LC;}
"}"		{return RC;}
[\n]            {yycolumn=1;}   
[ \r\t]         {}   
.		{printf("Error type A :Mysterious character \"%s\"\n\t at Line %d\n",yytext,yylineno);}
%%

int yywrap()
{
return 1;
}