在OS X上使用Flex(词法分析器) [英] Using Flex (the lexical analizer) on OS X

问题描述

我有一个文件test.lex，我将其运行为

I've got a file, test.lex, which I run through as

$ flex test.lex

这给了我lex.yy.c，我尝试用它编译:

That gives me lex.yy.c, which I try to compile with:

$ gcc lex.yy.c -lfl

这给我错误ld:-lfl找不到库.我知道Flex规范是正确的，并且lex.yy.c在Linux机器上可以正常编译.有什么建议吗?

This gives me the error ld: library not found for -lfl. I know the Flex specification is correct and lex.yy.c compiles fine on a Linux machine. Any suggestions?

我正在使用Apple提供的flex.

I'm using the flex supplied by Apple.

推荐答案

某些系统将libfl与flex分开，这是很少需要的. libfl库仅包含两个函数:

Some systems make libfl a separate package from flex, as it is rarely needed. The libfl library just contains two functions:

int main() {
    while (yylex());
    return 0;
}

int yywrap() {
    return 1;
}

通常，您将需要自己的main函数，而不是libfl中的函数，并且自己定义yywrap是微不足道的.或者，您可以使用%option noyywrap而不需要它.

Normally you'll want your own main function rather than the one from libfl, and defining yywrap yourself is trivial. Alternately, you can use %option noyywrap and not need it at all.

在您的情况下，请尝试摆脱-lfl选项.如果您收到有关yywrap的错误，请在test.lex文件的第一部分中添加
%option noyywrap.

In your case, try just getting rid of the -lfl option. If you get an error about yywrap, add
%option noyywrap to the first section of your test.lex file.

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