?? 促使我寫此正則表達式解析庫的由來.htm
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<p class=MsoNormal><span lang=EN-US><a href="#初衷"><span style='font-family:
宋體'>初衷</span></a></span></p>
<p class=MsoNormal><span lang=EN-US><a href="#我想說的"><span style='font-family:
宋體'>我想說的</span></a></span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><a name=初衷><span style='font-family:宋體'>大家好</span></a><span
style='font-family:宋體'>！</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋體'>我所知道的正則表達式庫有：</span><span lang=EN-US>boost</span><span
style='font-family:宋體'>的，</span><span lang=EN-US>GNU</span><span
style='font-family:宋體'>的，</span><span lang=EN-US>VC7</span><span
style='font-family:宋體'>帶的</span><span lang=EN-US>ATL</span><span
style='font-family:宋體'>中的和微軟發布的</span><span lang=EN-US>greta</span><span
style='font-family:宋體'>。我使用過后三種，</span><span lang=EN-US>greta</span><span
style='font-family:宋體'>使用時間最短（才兩天）。</span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋體'>現在我來說說我的感受：</span></p>
<p class=MsoNormal><span lang=EN-US> GNU</span><span
style='font-family:宋體'>的正則表達式根本就不支持多字節碼，設置連</span><span lang=EN-US>UNICODE</span><span
style='font-family:宋體'>都不支持，在</span><span lang=EN-US>parse</span><span
style='font-family:宋體'>階段就會非法操作。在軟件全球化的今天，實在不是一個好現象。優點是支持的語法完備。</span></p>
<p class=MsoNormal><span lang=EN-US> ATL</span><span
style='font-family:宋體'>中的正則表達式不完全支持多字節碼，可以完善的支持</span><span lang=EN-US>UNICODE</span><span
style='font-family:宋體'>。不過，此正則表達式書寫非常清晰，沒有用到</span><span lang=EN-US>STL</span><span
style='font-family:宋體'>里面任何高深的東西，也沒有用到模板中特別高深的東西</span><span lang=EN-US>(</span><span
style='font-family:宋體'>我認為這才是</span><span lang=EN-US>C++</span><span
style='font-family:宋體'>的發展之道，畢竟，聰明人是少數——大部分是平庸的人，曲高寡合，總有一天會被大多數程序員拋棄</span><span
lang=EN-US>,</span><span style='font-family:宋體'>剩下一幫高手顧影自憐），所以，通過非常微小和容易的更改就可以完善支持多字節碼。缺點是不支持</span><span
lang=EN-US>{n,m}</span><span style='font-family:宋體'>語法，不支持遞歸語法，如：</span><span
lang=EN-US>"([^\\"]*(\\.)*[^\\"]*)*"</span><span
style='font-family:宋體'>。最后一個</span><span lang=EN-US>*</span><span
style='font-family:宋體'>是不被支持的。</span></p>
<p class=MsoNormal><span lang=EN-US> greta</span><span
style='font-family:宋體'>能完善的支持單字節碼和</span><span lang=EN-US>UNICODE</span><span
style='font-family:宋體'>，語法也完善，而且據說普遍情況下速度也快，不過，把部分實現放</span><span lang=EN-US>cpp</span><span
style='font-family:宋體'>里導致不能同時使用單字節碼和</span><span lang=EN-US>UNICODE</span><span
style='font-family:宋體'>編碼，</span><span lang=EN-US>posix</span><span
style='font-family:宋體'>和</span><span lang=EN-US>perl</span><span
style='font-family:宋體'>語法，解決辦法還算簡單：把</span><span lang=EN-US>cpp</span><span
style='font-family:宋體'>改名為</span><span lang=EN-US>inl</span><span
style='font-family:宋體'>，在</span><span lang=EN-US>.h</span><span
style='font-family:宋體'>里</span><span lang=EN-US>include</span><span
style='font-family:宋體'>這個</span><span lang=EN-US>inl</span><span
style='font-family:宋體'>，再修改一點別的東西就可。問題是，它沒有支持多字節碼的實現，我仔細看看了，似乎通過自己寫一個多字節碼的迭代子，可以解決這個問題，因為他支持</span><span
lang=EN-US>basic_string</span><span style='font-family:宋體'>。</span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋體'>接下來的問題是：</span><span lang=EN-US>STL</span><span
style='font-family:宋體'>如何支持多字節碼的？我沒有在</span><span lang=EN-US>SGI-STL</span><span
style='font-family:宋體'>，</span><span lang=EN-US>STLPort453</span><span
style='font-family:宋體'>中找到關于多字節碼的東西。</span><span lang=EN-US>basic_string</span><span
style='font-family:宋體'>默認只實現了</span><span lang=EN-US>char,wchar_t</span><span
style='font-family:宋體'>的</span><span lang=EN-US>base_string</span><span
style='font-family:宋體'>。而要自己實現一個迭代子，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:宋體'>我現在的需求是：</span><span lang=EN-US> </span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋體'>需要正則表達式支持類似這樣的語法：“</span><span lang=EN-US>/</span><span
style='font-family:宋體'>漢字</span><span lang=EN-US>[</span><span
style='font-family:宋體'> </span><span lang=EN-US> ]+[^</span><span
style='font-family:宋體'> ，</span><span lang=EN-US> ,]+[</span><span
style='font-family:宋體'> </span><span lang=EN-US> ]*[</span><span
style='font-family:宋體'>，</span><span lang=EN-US>,][</span><span
style='font-family:宋體'> </span><span lang=EN-US> ]*[^</span><span
style='font-family:宋體'> ，</span><span lang=EN-US> ,]+</span><span
style='font-family:宋體'>”以匹配“／漢字 蘭征鵬 ，正則表達式”。</span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋體'>使用</span><span lang=EN-US>STL</span><span
style='font-family:宋體'>進行字符串搜索都有問題，比如在一篇文章中搜索“正則”，很可能就把三個漢字的中間四個字節匹配上了。出現這樣的情況，讓人哭笑不得。</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span lang=EN-US> </span><span
style='font-family:宋體'>有這方面經驗的或對</span><span lang=EN-US>STL</span><span
style='font-family:宋體'>比較熟悉的同仁，請勿吝嗇指導</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span style='font-family:宋體'> 致</span></p>
<p class=MsoNormal><span style='font-family:宋體'>禮！</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span style='font-family:宋體'> </span><span
lang=EN-US>lanzhengpeng</span></p>
<p class=MsoNormal><span style='font-family:宋體'> </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:宋體'>在</span><span
lang=EN-US>C/C++</span><span style='font-family:宋體'>中如果想要使用與</span><span
lang=EN-US>Perl</span><span style='font-family:宋體'>兼容的</span><span lang=EN-US>regexp</span><span
style='font-family:宋體'>庫，一個選擇是</span><span lang=EN-US>Boost</span><span
style='font-family:宋體'>，另一個選擇是</span><span lang=EN-US>PCRE</span></p>
<p class=MsoNormal><span style='font-family:宋體'>庫。</span><span lang=EN-US>Boost</span><span
style='font-family:宋體'>中的</span><span lang=EN-US>regex</span><span
style='font-family:宋體'>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:宋體'>倍，不過用起</span></p>
<p class=MsoNormal><span style='font-family:宋體'>來可能比較麻煩。</span><span
lang=EN-US>PCRE</span><span style='font-family:宋體'>已經很成熟了，</span><span
lang=EN-US>Apache/Postfix/PHP/Python</span><span style='font-family:宋體'>都用它。我認為應</span></p>
<p class=MsoNormal><span style='font-family:宋體'>該優先考慮。不過我自己沒有在</span><span
lang=EN-US>Windows</span><span style='font-family:宋體'>下編譯過，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:宋體'>我個人很喜歡</span><span lang=EN-US>Ruby</span><span
style='font-family:宋體'>中的正則表達式功能，功能強，速度也很不錯。因為</span><span lang=EN-US>Ruby</span><span
style='font-family:宋體'>是日本人發</span></p>
<p class=MsoNormal><span style='font-family:宋體'>明的，處理東亞大字符集沒有任何問題。</span><span
lang=EN-US>Ruby</span><span style='font-family:宋體'>與</span><span lang=EN-US>C/C++</span><span
style='font-family:宋體'>接口很容易，但是為了這個小功</span></p>
<p class=MsoNormal><span style='font-family:宋體'>能加入</span><span lang=EN-US>Ruby</span><span
style='font-family:宋體'>，似乎有點小題大做了。</span><span lang=EN-US>Perl</span><span
style='font-family:宋體'>我不熟悉。</span><span lang=EN-US>Lua</span><span
style='font-family:宋體'>獨創了一套模式匹配語法，而</span></p>
<p class=MsoNormal><span style='font-family:宋體'>且</span><span lang=EN-US>Lua</span><span
style='font-family:宋體'>天生就是要嵌入到</span><span lang=EN-US>C/C++</span><span
style='font-family:宋體'>中去的，性能比</span><span lang=EN-US>Perl/Ruby/Python</span><span
style='font-family:宋體'>都快的多。</span><span lang=EN-US>Lua</span><span
style='font-family:宋體'>的模式</span></p>
<p class=MsoNormal><span style='font-family:宋體'>匹配語法有點怪，解決</span><span
lang=EN-US>lanzhengpeng</span><span style='font-family:宋體'>的問題好像是足夠的，不過跟標準</span><span
lang=EN-US>regex</span><span style='font-family:宋體'>語法完全</span></p>
<p class=MsoNormal><span style='font-family:宋體'>不同。</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span style='font-family:宋體'>我個人的感覺，不如靜下心來寫一個</span><span
lang=EN-US>iterator</span><span style='font-family:宋體'>，應該是很容易的。不過我也很久沒干過</span></p>
<p class=MsoNormal><span style='font-family:宋體'>這種事情了，也就泛泛的說說算了。</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
<p class=MsoNormal><span style='font-family:宋體'>孟巖</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:宋體'>發件人</span><span lang=EN-US>: kyo</span></p>
<p class=MsoNormal><span style='font-family:宋體'>發送時間</span><span lang=EN-US>:
2004</span><span style='font-family:宋體'>年</span><span lang=EN-US>6</span><span
style='font-family:宋體'>月</span><span lang=EN-US>2</span><span style='font-family:
宋體'>日</span><span lang=EN-US> 11:19</span></p>
<p class=MsoNormal><span style='font-family:宋體'>收件人</span><span lang=EN-US>:
'C++ Discuss Group'</span></p>
<p class=MsoNormal><span style='font-family:宋體'>主題</span><span lang=EN-US>: RE:
[cpp]</span><span style='font-family:宋體'>正則表達式和多字節碼的問題</span></p>
<p class=MsoNormal><span lang=EN-US> </span></p>
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