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diff --git a/libstdc++-v3/docs/html/22_locale/howto.html b/libstdc++-v3/docs/html/22_locale/howto.html deleted file mode 100644 index 3d19bb69a62..00000000000 --- a/libstdc++-v3/docs/html/22_locale/howto.html +++ /dev/null @@ -1,240 +0,0 @@ -<?xml version="1.0" encoding="ISO-8859-1"?> -<!DOCTYPE html - PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" - "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> - -<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> -<head> - <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> - <meta name="AUTHOR" content="pme@gcc.gnu.org (Phil Edwards)" /> - <meta name="KEYWORDS" content="HOWTO, libstdc++, GCC, g++, libg++, STL" /> - <meta name="DESCRIPTION" content="HOWTO for the libstdc++ chapter 22." /> - <meta name="GENERATOR" content="vi and eight fingers" /> - <title>libstdc++-v3 HOWTO: Chapter 22: Localization</title> -<link rel="StyleSheet" href="../lib3styles.css" type="text/css" /> -<link rel="Start" href="../documentation.html" type="text/html" - title="GNU C++ Standard Library" /> -<link rel="Prev" href="../21_strings/howto.html" type="text/html" - title="Strings" /> -<link rel="Next" href="../23_containers/howto.html" type="text/html" - title="Containers" /> -<link rel="Bookmark" href="locale.html" type="text/html" title="class locale" /> -<link rel="Bookmark" href="codecvt.html" type="text/html" title="class codecvt" /> -<link rel="Bookmark" href="ctype.html" type="text/html" title="class ctype" /> -<link rel="Bookmark" href="messages.html" type="text/html" title="class messages" /> -<link rel="Bookmark" href="http://www.research.att.com/~bs/3rd_loc0.html" type="text/html" title="Bjarne Stroustrup on Locales" /> -<link rel="Bookmark" href="http://www.cantrip.org/locale.html" type="text/html" title="Nathan Myers on Locales" /> -<link rel="Copyright" href="../17_intro/license.html" type="text/html" /> -<link rel="Help" href="../faq/index.html" type="text/html" title="F.A.Q." /> -</head> -<body> - -<h1 class="centered"><a name="top">Chapter 22: Localization</a></h1> - -<p>Chapter 22 deals with the C++ localization facilities. -</p> -<!-- I wanted to write that sentence in something requiring an exotic font, - like Cyrllic or Kanji. Probably more work than such cuteness is worth, - but I still think it'd be funny. - --> - - -<!-- ####################################################### --> -<hr /> -<h1>Contents</h1> -<ul> - <li><a href="#1">class locale</a></li> - <li><a href="#2">class codecvt</a></li> - <li><a href="#3">class ctype</a></li> - <li><a href="#4">class messages</a></li> - <li><a href="#5">Bjarne Stroustrup on Locales</a></li> - <li><a href="#6">Nathan Myers on Locales</a></li> - <li><a href="#7">Correct Transformations</a></li> -</ul> - -<!-- ####################################################### --> - -<hr /> -<h2><a name="1">class locale</a></h2> - <p>Notes made during the implementation of locales can be found - <a href="locale.html">here</a>. - </p> - -<hr /> -<h2><a name="2">class codecvt</a></h2> - <p>Notes made during the implementation of codecvt can be found - <a href="codecvt.html">here</a>. - </p> - - <p>The following is the abstract from the implementation notes: - </p> - <blockquote> - The standard class codecvt attempts to address conversions between - different character encoding schemes. In particular, the standard - attempts to detail conversions between the implementation-defined - wide characters (hereafter referred to as wchar_t) and the standard - type char that is so beloved in classic "C" (which can - now be referred to as narrow characters.) This document attempts - to describe how the GNU libstdc++-v3 implementation deals with the - conversion between wide and narrow characters, and also presents a - framework for dealing with the huge number of other encodings that - iconv can convert, including Unicode and UTF8. Design issues and - requirements are addressed, and examples of correct usage for both - the required specializations for wide and narrow characters and the - implementation-provided extended functionality are given. - </blockquote> - -<hr /> -<h2><a name="3">class ctype</a></h2> - <p>Notes made during the implementation of ctype can be found - <a href="ctype.html">here</a>. - </p> - -<hr /> -<h2><a name="4">class messages</a></h2> - <p>Notes made during the implementation of messages can be found - <a href="messages.html">here</a>. - </p> - -<hr /> -<h2><a name="5">Bjarne Stroustrup on Locales</a></h2> - <p>Dr. Bjarne Stroustrup has released a - <a href="http://www.research.att.com/~bs/3rd_loc0.html">pointer</a> - to Appendix D of his book, - <a href="http://www.research.att.com/~bs/3rd.html">The C++ - Programming Language (3rd Edition)</a>. It is a detailed - description of locales and how to use them. - </p> - <p>He also writes: - </p> - <blockquote><em> - Please note that I still consider this detailed description of - locales beyond the needs of most C++ programmers. It is written - with experienced programmers in mind and novices will do best to - avoid it. - </em></blockquote> - -<hr /> -<h2><a name="6">Nathan Myers on Locales</a></h2> - <p>An article entitled "The Standard C++ Locale" was - published in Dr. Dobb's Journal and can be found - <a href="http://www.cantrip.org/locale.html">here</a>. - </p> - -<hr /> -<h2><a name="7">Correct Transformations</a></h2> - <!-- Jumping directly to here from chapter 21. --> - <p>A very common question on newsgroups and mailing lists is, "How - do I do <foo> to a character string?" where <foo> is - a task such as changing all the letters to uppercase, to lowercase, - testing for digits, etc. A skilled and conscientious programmer - will follow the question with another, "And how do I make the - code portable?" - </p> - <p>(Poor innocent programmer, you have no idea the depths of trouble - you are getting yourself into. 'Twould be best for your sanity if - you dropped the whole idea and took up basket weaving instead. No? - Fine, you asked for it...) - </p> - <p>The task of changing the case of a letter or classifying a character - as numeric, graphical, etc., all depends on the cultural context of the - program at runtime. So, first you must take the portability question - into account. Once you have localized the program to a particular - natural language, only then can you perform the specific task. - Unfortunately, specializing a function for a human language is not - as simple as declaring - <code> extern "Danish" int tolower (int); </code>. - </p> - <p>The C++ code to do all this proceeds in the same way. First, a locale - is created. Then member functions of that locale are called to - perform minor tasks. Continuing the example from Chapter 21, we wish - to use the following convenience functions: - </p> - <pre> - namespace std { - template <class charT> - charT - toupper (charT c, const locale& loc) const; - template <class charT> - charT - tolower (charT c, const locale& loc) const; - }</pre> - <p> - This function extracts the appropriate "facet" from the - locale <em>loc</em> and calls the appropriate member function of that - facet, passing <em>c</em> as its argument. The resulting character - is returned. - </p> - <p>For the C/POSIX locale, the results are the same as calling the - classic C <code>toupper/tolower</code> function that was used in previous - examples. For other locales, the code should Do The Right Thing. - </p> - <p>Of course, these functions take a second argument, and the - transformation algorithm's operator argument can only take a single - parameter. So we write simple wrapper structs to handle that. - </p> - <p>The next-to-final version of the code started in Chapter 21 looks like: - </p> - <pre> - #include <iterator> // for back_inserter - #include <locale> - #include <string> - #include <algorithm> - #include <cctype> // old <ctype.h> - - struct ToUpper - { - ToUpper(std::locale const& l) : loc(l) {;} - char operator() (char c) const { return std::toupper(c,loc); } - private: - std::locale const& loc; - }; - - struct ToLower - { - ToLower(std::locale const& l) : loc(l) {;} - char operator() (char c) const { return std::tolower(c,loc); } - private: - std::locale const& loc; - }; - - int main () - { - std::string s("Some Kind Of Initial Input Goes Here"); - ToUpper up(std::locale::classic()); - ToLower down(std::locale::classic()); - - // Change everything into upper case. - std::transform(s.begin(), s.end(), s.begin(), up); - - // Change everything into lower case. - std::transform(s.begin(), s.end(), s.begin(), down); - - // Change everything back into upper case, but store the - // result in a different string. - std::string capital_s; - std::transform(s.begin(), s.end(), std::back_inserter(capital_s), up); - }</pre> - <p>The <code>ToUpper</code> and <code>ToLower</code> structs can be - generalized for other character types by making <code>operator()</code> - a member function template. - </p> - <p>The final version of the code uses <code>bind2nd</code> to eliminate - the wrapper structs, but the resulting code is tricky. I have not - shown it here because no compilers currently available to me will - handle it. - </p> - - -<!-- ####################################################### --> - -<hr /> -<p class="fineprint"><em> -See <a href="../17_intro/license.html">license.html</a> for copying conditions. -Comments and suggestions are welcome, and may be sent to -<a href="mailto:libstdc++@gcc.gnu.org">the libstdc++ mailing list</a>. -</em></p> - - -</body> -</html> |