📄 促使我写此正则表达式解析库的由来.htm
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<p class=MsoNormal><span lang=EN-US><a href="#初衷"><span style='font-family:
宋体'>初衷</span></a></span></p>
<p class=MsoNormal><span lang=EN-US><a href="#我想说的"><span style='font-family:
宋体'>我想说的</span></a></span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><a name=初衷><span style='font-family:宋体'>大家好</span></a><span
style='font-family:宋体'>！</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋体'>我所知道的正则表达式库有：</span><span lang=EN-US>boost</span><span
style='font-family:宋体'>的，</span><span lang=EN-US>GNU</span><span
style='font-family:宋体'>的，</span><span lang=EN-US>VC7</span><span
style='font-family:宋体'>带的</span><span lang=EN-US>ATL</span><span
style='font-family:宋体'>中的和微软发布的</span><span lang=EN-US>greta</span><span
style='font-family:宋体'>。我使用过后三种，</span><span lang=EN-US>greta</span><span
style='font-family:宋体'>使用时间最短（才两天）。</span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋体'>现在我来说说我的感受：</span></p>
<p class=MsoNormal><span lang=EN-US> GNU</span><span
style='font-family:宋体'>的正则表达式根本就不支持多字节码，设置连</span><span lang=EN-US>UNICODE</span><span
style='font-family:宋体'>都不支持，在</span><span lang=EN-US>parse</span><span
style='font-family:宋体'>阶段就会非法操作。在软件全球化的今天，实在不是一个好现象。优点是支持的语法完备。</span></p>
<p class=MsoNormal><span lang=EN-US> ATL</span><span
style='font-family:宋体'>中的正则表达式不完全支持多字节码，可以完善的支持</span><span lang=EN-US>UNICODE</span><span
style='font-family:宋体'>。不过，此正则表达式书写非常清晰，没有用到</span><span lang=EN-US>STL</span><span
style='font-family:宋体'>里面任何高深的东西，也没有用到模板中特别高深的东西</span><span lang=EN-US>(</span><span
style='font-family:宋体'>我认为这才是</span><span lang=EN-US>C++</span><span
style='font-family:宋体'>的发展之道，毕竟，聪明人是少数——大部分是平庸的人，曲高寡合，总有一天会被大多数程序员抛弃</span><span
lang=EN-US>,</span><span style='font-family:宋体'>剩下一帮高手顾影自怜），所以，通过非常微小和容易的更改就可以完善支持多字节码。缺点是不支持</span><span
lang=EN-US>{n,m}</span><span style='font-family:宋体'>语法，不支持递归语法，如：</span><span
lang=EN-US>"([^\\"]*(\\.)*[^\\"]*)*"</span><span
style='font-family:宋体'>。最后一个</span><span lang=EN-US>*</span><span
style='font-family:宋体'>是不被支持的。</span></p>
<p class=MsoNormal><span lang=EN-US> greta</span><span
style='font-family:宋体'>能完善的支持单字节码和</span><span lang=EN-US>UNICODE</span><span
style='font-family:宋体'>，语法也完善，而且据说普遍情况下速度也快，不过，把部分实现放</span><span lang=EN-US>cpp</span><span
style='font-family:宋体'>里导致不能同时使用单字节码和</span><span lang=EN-US>UNICODE</span><span
style='font-family:宋体'>编码，</span><span lang=EN-US>posix</span><span
style='font-family:宋体'>和</span><span lang=EN-US>perl</span><span
style='font-family:宋体'>语法，解决办法还算简单：把</span><span lang=EN-US>cpp</span><span
style='font-family:宋体'>改名为</span><span lang=EN-US>inl</span><span
style='font-family:宋体'>，在</span><span lang=EN-US>.h</span><span
style='font-family:宋体'>里</span><span lang=EN-US>include</span><span
style='font-family:宋体'>这个</span><span lang=EN-US>inl</span><span
style='font-family:宋体'>，再修改一点别的东西就可。问题是，它没有支持多字节码的实现，我仔细看看了，似乎通过自己写一个多字节码的迭代子，可以解决这个问题，因为他支持</span><span
lang=EN-US>basic_string</span><span style='font-family:宋体'>。</span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋体'>接下来的问题是：</span><span lang=EN-US>STL</span><span
style='font-family:宋体'>如何支持多字节码的？我没有在</span><span lang=EN-US>SGI-STL</span><span
style='font-family:宋体'>，</span><span lang=EN-US>STLPort453</span><span
style='font-family:宋体'>中找到关于多字节码的东西。</span><span lang=EN-US>basic_string</span><span
style='font-family:宋体'>默认只实现了</span><span lang=EN-US>char,wchar_t</span><span
style='font-family:宋体'>的</span><span lang=EN-US>base_string</span><span
style='font-family:宋体'>。而要自己实现一个迭代子，我又不知道如何下手。</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋体'>我现在的需求是：</span><span lang=EN-US> </span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋体'>需要正则表达式支持类似这样的语法：“</span><span lang=EN-US>/</span><span
style='font-family:宋体'>汉字</span><span lang=EN-US>[</span><span
style='font-family:宋体'> </span><span lang=EN-US> ]+[^</span><span
style='font-family:宋体'> ，</span><span lang=EN-US> ,]+[</span><span
style='font-family:宋体'> </span><span lang=EN-US> ]*[</span><span
style='font-family:宋体'>，</span><span lang=EN-US>,][</span><span
style='font-family:宋体'> </span><span lang=EN-US> ]*[^</span><span
style='font-family:宋体'> ，</span><span lang=EN-US> ,]+</span><span
style='font-family:宋体'>”以匹配“／汉字 兰征鹏 ，正则表达式”。</span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋体'>使用</span><span lang=EN-US>STL</span><span
style='font-family:宋体'>进行字符串搜索都有问题，比如在一篇文章中搜索“正则”，很可能就把三个汉字的中间四个字节匹配上了。出现这样的情况，让人哭笑不得。</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋体'>有这方面经验的或对</span><span lang=EN-US>STL</span><span
style='font-family:宋体'>比较熟悉的同仁，请勿吝啬指导</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span style='font-family:宋体'> 致</span></p>
<p class=MsoNormal><span style='font-family:宋体'>礼！</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span style='font-family:宋体'> </span><span
lang=EN-US>lanzhengpeng</span></p>
<p class=MsoNormal><span style='font-family:宋体'> </span><span
lang=EN-US>2004-06-02</span></p>
<p class=MsoNormal><span lang=EN-US>_______________________________________________</span></p>
<p class=MsoNormal><span lang=EN-US>Cpp mailing list</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span lang=EN-US> </span><span style='font-family:宋体'>在</span><span
lang=EN-US>C/C++</span><span style='font-family:宋体'>中如果想要使用与</span><span
lang=EN-US>Perl</span><span style='font-family:宋体'>兼容的</span><span lang=EN-US>regexp</span><span
style='font-family:宋体'>库，一个选择是</span><span lang=EN-US>Boost</span><span
style='font-family:宋体'>，另一个选择是</span><span lang=EN-US>PCRE</span></p>
<p class=MsoNormal><span style='font-family:宋体'>库。</span><span lang=EN-US>Boost</span><span
style='font-family:宋体'>中的</span><span lang=EN-US>regex</span><span
style='font-family:宋体'>算法最近做了改近，平均效率比以前的版本提高了</span><span lang=EN-US>10</span><span
style='font-family:宋体'>倍，不过用起</span></p>
<p class=MsoNormal><span style='font-family:宋体'>来可能比较麻烦。</span><span
lang=EN-US>PCRE</span><span style='font-family:宋体'>已经很成熟了，</span><span
lang=EN-US>Apache/Postfix/PHP/Python</span><span style='font-family:宋体'>都用它。我认为应</span></p>
<p class=MsoNormal><span style='font-family:宋体'>该优先考虑。不过我自己没有在</span><span
lang=EN-US>Windows</span><span style='font-family:宋体'>下编译过，不是很有把握。</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span lang=EN-US>See www.pcre.org</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span style='font-family:宋体'>我个人很喜欢</span><span lang=EN-US>Ruby</span><span
style='font-family:宋体'>中的正则表达式功能，功能强，速度也很不错。因为</span><span lang=EN-US>Ruby</span><span
style='font-family:宋体'>是日本人发</span></p>
<p class=MsoNormal><span style='font-family:宋体'>明的，处理东亚大字符集没有任何问题。</span><span
lang=EN-US>Ruby</span><span style='font-family:宋体'>与</span><span lang=EN-US>C/C++</span><span
style='font-family:宋体'>接口很容易，但是为了这个小功</span></p>
<p class=MsoNormal><span style='font-family:宋体'>能加入</span><span lang=EN-US>Ruby</span><span
style='font-family:宋体'>，似乎有点小题大做了。</span><span lang=EN-US>Perl</span><span
style='font-family:宋体'>我不熟悉。</span><span lang=EN-US>Lua</span><span
style='font-family:宋体'>独创了一套模式匹配语法，而</span></p>
<p class=MsoNormal><span style='font-family:宋体'>且</span><span lang=EN-US>Lua</span><span
style='font-family:宋体'>天生就是要嵌入到</span><span lang=EN-US>C/C++</span><span
style='font-family:宋体'>中去的，性能比</span><span lang=EN-US>Perl/Ruby/Python</span><span
style='font-family:宋体'>都快的多。</span><span lang=EN-US>Lua</span><span
style='font-family:宋体'>的模式</span></p>
<p class=MsoNormal><span style='font-family:宋体'>匹配语法有点怪，解决</span><span
lang=EN-US>lanzhengpeng</span><span style='font-family:宋体'>的问题好像是足够的，不过跟标准</span><span
lang=EN-US>regex</span><span style='font-family:宋体'>语法完全</span></p>
<p class=MsoNormal><span style='font-family:宋体'>不同。</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span style='font-family:宋体'>我个人的感觉，不如静下心来写一个</span><span
lang=EN-US>iterator</span><span style='font-family:宋体'>，应该是很容易的。不过我也很久没干过</span></p>
<p class=MsoNormal><span style='font-family:宋体'>这种事情了，也就泛泛的说说算了。</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span style='font-family:宋体'>孟岩</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span lang=EN-US>_______________________________________________</span></p>
<p class=MsoNormal><span lang=EN-US>Cpp mailing list</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span style='font-family:宋体'>发件人</span><span lang=EN-US>: kyo</span></p>
<p class=MsoNormal><span style='font-family:宋体'>发送时间</span><span lang=EN-US>:
2004</span><span style='font-family:宋体'>年</span><span lang=EN-US>6</span><span
style='font-family:宋体'>月</span><span lang=EN-US>2</span><span style='font-family:
宋体'>日</span><span lang=EN-US> 11:19</span></p>
<p class=MsoNormal><span style='font-family:宋体'>收件人</span><span lang=EN-US>:
'C++ Discuss Group'</span></p>
<p class=MsoNormal><span style='font-family:宋体'>主题</span><span lang=EN-US>: RE:
[cpp]</span><span style='font-family:宋体'>正则表达式和多字节码的问题</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
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