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- <?xml version="1.0" encoding="utf-8"?>
- <!DOCTYPE library PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
- "http://www.boost.org/tools/boostbook/dtd/boostbook.dtd">
- <!-- Copyright (c) 2002-2006 Pavol Droba.
- Subject to the Boost Software License, Version 1.0.
- (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
- -->
- <section id="string_algo.rationale" last-revision="$Date$">
- <title>Rationale</title>
- <using-namespace name="boost"/>
- <using-namespace name="boost::algorithm"/>
-
- <section it="string_algo.locale">
- <title>Locales</title>
- <para>
- Locales have a very close relation to string processing. They contain information about
- the character sets and are used, for example, to change the case of characters and
- to classify the characters.
- </para>
- <para>
- C++ allows to work with multiple different instances of locales at once. If an algorithm
- manipulates some data in a way that requires the usage of locales, there must be a way
- to specify them. However, one instance of locales is sufficient for most of the applications,
- and for a user it could be very tedious to specify which locales to use at every place
- where it is needed.
- </para>
- <para>
- Fortunately, the C++ standard allows to specify the <emphasis>global</emphasis> locales (using static member
- function <code>std:locale::global()</code>). When instantiating an
- <code>std::locale</code> class without explicit information, the instance will
- be initialized with the <emphasis>global</emphasis> locale. This implies, that if an algorithm needs a locale,
- it should have an <code>std::locale</code> parameter defaulting to <code>std::locale()</code>.
- If a user needs to specify locales explicitly, she can do so. Otherwise the <emphasis>global</emphasis>
- locales are used.
- </para>
- </section>
- <section id="string_algo.regex">
- <title>Regular Expressions</title>
- <para>
- Regular expressions are an essential part of text processing. For this reason, the library
- also provides regex variants of some algorithms. The library does not attempt to replace
- <libraryname>Boost.Regex</libraryname>; it merely wraps its functionality in a new interface.
- As a part of this library, regex algorithms integrate smoothly with other components, which
- brings additional value.
- </para>
- </section>
- </section>
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