flex

flex 词法分析

fb.l

%option noyywrap
%{
#include <stdio.h>
int chars = 0;
int words = 0;
int lines = 0;
%}

%%

[a-zA-Z]+    { words++; chars += strlen(yytext); }
\n            { chars++; lines++; }
.            { chars++; }

%%

int main(int argc, char **argv)
{
    yylex();
    printf("%8d%8d%8d\n", lines, words, chars);
}

 

$ flex fb.l

$ cc lex.yy.c

$ cat fb.l | ./a.out

 

%option noyywrap

http://stackoverflow.com/questions/1811125/undefined-reference-to-yywrap