mylexer.l

用LEX自动生成的C-词法分析程序 (能识别注释)

%{
/****************************************************************************
mylexer.l
ParserWizard generated Lex file.

Date: 2007年11月1日
****************************************************************************/
#include <stdio.h>
#include <string.h>
#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif



typedef enum{HEAD,ELSE,IF,INT,RETURN,VOID,WHILE,LT,GT,LE,GE,EQ,NE,COMMENT,LETTER,DIGIT,ID,NUMBER} TOKEN;

%}

/////////////////////////////////////////////////////////////////////////////
// declarations section

// place any declarations here
letter [A-Za-z]
digit [0-9]
id {letter}{letter}*
number {digit}{digit}*


%%

/////////////////////////////////////////////////////////////////////////////
// rules section

// place your Lex rules here


"else" {printf("ELSE:%s%c ",yytext,' ');return ELSE;}
"if" {printf("IF:%s%c ",yytext,' ');return IF;}
"int" {printf("INT:%s%c ",yytext,' ');return INT;}
"return" {printf("RETURN:%s%c ",yytext,' ');return RETURN;}
"void" {printf("VOID:%s%c ",yytext,' ');return VOID;}
"while" {printf("WHILE:%s%c ",yytext,' ');return WHILE;}

"<" {printf("LT:%s%c ",yytext,' ');return LT;}
">" {printf("GT:%s%c ",yytext,' ');return GT;}
"<=" {printf("LE:%s%c ",yytext,' ');return LE;}
">=" {printf("GE:%s%c ",yytext,' ');return GE;}
"==" {printf("EQ:%s%c ",yytext,' ');return EQ;}
"!=" {printf("NE:%s%c ",yytext,' ');return NE;}
"{" {printf("{:%s%c ",yytext,' '); return '{';}
"}" {printf("}:%s%c ",yytext,' '); return '}';}
"(" {printf("(:%s%c ",yytext,' ');return '(';}
")" {printf("):%s%c ",yytext,' ');return ')';}
"[" {printf("[:%s%c ",yytext,' ');return '[';}
"]" {printf("]:%s%c ",yytext,' ');return ']';}
"+" {printf("+:%s%c ",yytext,' ');return '+';}
"-" {printf("-:%s%c ",yytext,' ');return '-';}
"*" {printf("*:%s%c ",yytext,' ');return '*';}
"/" {printf("/:%s%c ",yytext,' ');return '/';}
"%" {printf("%:%s%c ",yytext,' ');return '%';}
";" {printf(";:%s%c ",yytext,' ');return ';';}
"=" {printf("=:%s%c ",yytext,' ');return '=';}
"," {printf(",:%s%c ",yytext,' ');return ',';}
{id} {printf("id:%s%c ",yytext,' ');return ID;}

{number} {printf("number:%s%c ",yytext,' '); return NUMBER;}

"/*" {  		
		char c;
		int done = FALSE;
		ECHO;
		do
		{	while((c=input())!='*')
				putchar(c);
			putchar(c);
			while((c=input())=='*')
				putchar(c);
			putchar(c);
			if(c=='/') done =TRUE;
		} while(!done);
		
		printf("\n: There are the conment!");
		return COMMENT;
	}

%%

/////////////////////////////////////////////////////////////////////////////
// programs section

int main(void)
{
	while (yylex()) ;

}