forked from boostorg/regex
67 lines
3.3 KiB
HTML
67 lines
3.3 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<html>
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<head>
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<title>Boost.Regex: Index</title>
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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<link rel="stylesheet" type="text/css" href="../../../boost.css">
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</head>
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<body>
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<P>
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<TABLE id="Table1" cellSpacing="1" cellPadding="1" width="100%" border="0">
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<TR>
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<td valign="top" width="300">
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<h3><a href="../../../index.htm"><img height="86" width="277" alt="C++ Boost" src="../../../boost.png" border="0"></a></h3>
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</td>
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<TD width="353">
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<H1 align="center">Boost.Regex</H1>
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<H2 align="center">Unicode Regular Expressions.</H2>
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</TD>
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<td width="50">
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<h3><a href="index.html"><img height="45" width="43" alt="Boost.Regex Index" src="uarrow.gif" border="0"></a></h3>
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</td>
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</TR>
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</TABLE>
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</P>
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<HR>
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<p></p>
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<P>There are two ways to use Boost.Regex with Unicode strings:</P>
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<H3>Rely on wchar_t</H3>
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<P>If your platform's wchar_t type can hold Unicode strings, <EM>and</EM> your
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platform's C/C++ runtime correctly handles wide character constants (when
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passed to std::iswspace std::iswlower etc), then you can use boost::wregex to
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process Unicode. However, there are several disadvantages to this
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approach:</P>
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<UL>
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<LI>
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It's not portable: there's no guarantee on the width of wchar_t, or even
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whether the runtime treats wide characters as Unicode at all, most Windows
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compilers do so, but many Unix systems do not.</LI>
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<LI>
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There's no support for Unicode-specific character classes: [[:Nd:]], [[:Po:]]
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etc.</LI>
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<LI>
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You can only search strings that are encoded as sequences of wide characters,
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it is not possible to search UTF-8, or even UTF-16 on many platforms.</LI></UL>
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<H3>Use a Unicode Aware Regular Expression Type.</H3>
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<P>If you have the <A href="http://www.ibm.com/software/globalization/icu/">ICU
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library</A>, then Boost.Regex can be <A href="install.html#unicode">configured
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to make use of it</A>, and provide a distinct regular expression type
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(boost::u32regex), that supports both Unicode specific character properties,
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and the searching of text that is encoded in either UTF-8, UTF-16, or
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UTF-32. See: <A href="icu_strings.html">ICU string class support</A>.</P>
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<P>
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<HR>
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</P>
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<P></P>
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<p>Revised
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<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
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04 Jan 2005
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<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
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<p><i><EFBFBD> Copyright John Maddock 2005</i></p>
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<P><I>Use, modification and distribution are subject to the Boost Software License,
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Version 1.0. (See accompanying file <A href="../../../LICENSE_1_0.txt">LICENSE_1_0.txt</A>
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or copy at <A href="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</A>)</I></P>
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</body>
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</html>
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