algorithm/string/doc/rationale.xml
Daniel James 822636418b Merged revisions 43211,43214-43219,43222-43225,43227-43238,43242,43244-43245,43249-43250,43257-43259,43261,43263,43265,43267-43268,43270-43271,43273,43275-43279,43284-43289,43291,43295,43297-43298,43304-43305,43307,43313,43315,43324,43326-43327,43331,43333,43339-43343,43345,43348,43350,43352-43353,43355-43356,43358,43360,43366-43367,43369-43370,43372-43376,43378-43389,43394,43396-43398,43400-43401,43403-43404,43406-43408,43413-43415,43417-43418,43420,43422-43423 via svnmerge from
https://svn.boost.org/svn/boost/trunk

........
  r43417 | danieljames | 2008-02-26 22:04:55 +0000 (Tue, 26 Feb 2008) | 2 lines
  
  Fix a link to Boost.Bimap.
........
  r43418 | danieljames | 2008-02-26 22:07:25 +0000 (Tue, 26 Feb 2008) | 2 lines
  
  Change another link that's no longer in the repository to link to the website.
........
  r43422 | danieljames | 2008-02-27 18:51:14 +0000 (Wed, 27 Feb 2008) | 1 line
  
  Fix broken copyright urls. Fixes #1573.
........
  r43423 | danieljames | 2008-02-27 19:22:01 +0000 (Wed, 27 Feb 2008) | 1 line
  
  Fix incorrect links to copyright of the form 'http:#www.boost.org
........


[SVN r43425]
2008-02-27 20:00:24 +00:00

53 lines
2.6 KiB
XML

<?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>