mirror of
git://gcc.gnu.org/git/gcc.git
synced 2025-04-13 15:51:01 +08:00
thanks.html: More thanks.
2000-09-19 Phil Edwards <pme@sources.redhat.com> * docs/thanks.html: More thanks. * docs/18_support/howto.html: Fix thinko. * docs/21_strings/howto.html: Minor tweaks and updates to URLs. Redo the string transformation notes and link to... * docs/22_locale/howto.html: ...here. From-SVN: r36546
This commit is contained in:
Phil Edwards
parent
7eea5554ce
commit
3c1fd79ba9
libstdc++-v3
@ -1,3 +1,11 @@
|
||||
2000-09-19 Phil Edwards <pme@sources.redhat.com>
|
||||
|
||||
* docs/thanks.html: More thanks.
|
||||
* docs/18_support/howto.html: Fix thinko.
|
||||
* docs/21_strings/howto.html: Minor tweaks and updates to URLs.
|
||||
Redo the string transformation notes and link to...
|
||||
* docs/22_locale/howto.html: ...here.
|
||||
|
||||
2000-09-18 Benjamin Kosnik <bkoz@purist.soma.redhat.com>
|
||||
|
||||
* src/locale-inst.cc: Add time_put_byname and
|
||||
|
||||
@ -9,7 +9,7 @@
|
||||
<TITLE>libstdc++-v3 HOWTO: Chapter 18</TITLE>
|
||||
<LINK REL="home" HREF="http://sources.redhat.com/libstdc++/docs/18_support/">
|
||||
<LINK REL=StyleSheet HREF="../lib3styles.css">
|
||||
<!-- $Id: howto.html,v 1.3 2000/07/11 21:45:07 pme Exp $ -->
|
||||
<!-- $Id: howto.html,v 1.4 2000/07/19 20:20:51 pme Exp $ -->
|
||||
</HEAD>
|
||||
<BODY>
|
||||
|
||||
@ -228,7 +228,7 @@
|
||||
|
||||
void my_new_handler ()
|
||||
{
|
||||
delete safety;
|
||||
delete[] safety;
|
||||
popup_window ("Dude, you are running low on heap memory. You
|
||||
should, like, close some windows, or something.
|
||||
The next time you run out, we're gonna burn!");
|
||||
@ -262,7 +262,7 @@
|
||||
Comments and suggestions are welcome, and may be sent to
|
||||
<A HREF="mailto:pme@sources.redhat.com">Phil Edwards</A> or
|
||||
<A HREF="mailto:gdr@egcs.cygnus.com">Gabriel Dos Reis</A>.
|
||||
<BR> $Id: howto.html,v 1.3 2000/07/11 21:45:07 pme Exp $
|
||||
<BR> $Id: howto.html,v 1.4 2000/07/19 20:20:51 pme Exp $
|
||||
</EM></P>
|
||||
|
||||
|
||||
|
||||
@ -9,7 +9,7 @@
|
||||
<TITLE>libstdc++-v3 HOWTO: Chapter 21</TITLE>
|
||||
<LINK REL="home" HREF="http://sources.redhat.com/libstdc++/docs/21_strings/">
|
||||
<LINK REL=StyleSheet HREF="../lib3styles.css">
|
||||
<!-- $Id: howto.html,v 1.2 2000/07/07 21:13:28 pme Exp $ -->
|
||||
<!-- $Id: howto.html,v 1.3 2000/07/11 21:45:07 pme Exp $ -->
|
||||
</HEAD>
|
||||
<BODY>
|
||||
|
||||
@ -42,7 +42,7 @@
|
||||
are relying on special functons offered by the CString class.
|
||||
</P>
|
||||
<P>Things are not as bad as they seem. In
|
||||
<A HREF="http://egcs.cygnus.com/ml/egcs/1999-04/msg00233.html">this
|
||||
<A HREF="http://gcc.gnu.org/ml/egcs/1999-04/msg00233.html">this
|
||||
message</A>, Joe Buck points out a few very important things:
|
||||
<UL>
|
||||
<LI>The Standard <TT>string</TT> supports all the operations
|
||||
@ -66,7 +66,7 @@
|
||||
#include <string>
|
||||
#include <sstream>
|
||||
|
||||
string f (string& incoming) // incoming is something like "foo N"
|
||||
string f (string& incoming) // incoming is "foo N"
|
||||
{
|
||||
istringstream incoming_stream(incoming);
|
||||
string the_word;
|
||||
@ -88,7 +88,7 @@
|
||||
CString suffers from a common programming error that results in
|
||||
poor performance. Consider the following code:
|
||||
|
||||
CString n_copies_of (const CString& foo, unsigned n)
|
||||
CString n_copies_of (const CString& foo, unsigned n)
|
||||
{
|
||||
CString tmp;
|
||||
for (unsigned i = 0; i < n; i++)
|
||||
@ -158,8 +158,10 @@
|
||||
</P>
|
||||
|
||||
<P>The solution is surprisingly easy. The original answer pages
|
||||
on the GotW website have been removed into cold storage, in
|
||||
preparation for a published book of GotW notes. Before being
|
||||
on the GotW website were removed into cold storage, in
|
||||
preparation for
|
||||
<A HREF="http://cseng.aw.com/bookpage.taf?ISBN=0-201-61562-2">a
|
||||
published book of GotW notes</A>. Before being
|
||||
put on the web, of course, it was posted on Usenet, and that
|
||||
posting containing the answer is <A HREF="gotw29a.txt">available
|
||||
here</A>.
|
||||
@ -170,7 +172,7 @@
|
||||
on why case-insensitive comparisons are not as easy as they seem,
|
||||
and why creating a class is the <EM>wrong</EM> way to go about it in
|
||||
production code. (The GotW answer mentions one of the principle
|
||||
difficulties; this article mentions more.)
|
||||
difficulties; his article mentions more.)
|
||||
</P>
|
||||
<P>Basically, this is "easy" only if you ignore some things,
|
||||
things which may be too important to your program to ignore. (I chose
|
||||
@ -178,6 +180,11 @@
|
||||
that nobody ever called me on it...) The GotW question and answer
|
||||
remain useful instructional tools, however.
|
||||
</P>
|
||||
<P><B>Added September 2000:</B> James Kanze provided a link to a
|
||||
<A HREF="http://www.unicode.org/unicode/reports/tr21/">Unicode
|
||||
Technical Report discussing case handling</A>, which provides some
|
||||
very good information.
|
||||
</P>
|
||||
<P>Return <A HREF="#top">to top of page</A> or
|
||||
<A HREF="../faq/index.html">to the FAQ</A>.
|
||||
</P>
|
||||
@ -204,9 +211,9 @@
|
||||
a more general (but less readable) form of it for parsing command
|
||||
strings and the like. If you compiled and ran this code using it:
|
||||
<PRE>
|
||||
std::list<string> ls;
|
||||
std::list<string> ls;
|
||||
stringtok (ls, " this \t is\t\n a test ");
|
||||
for (std::list<string>::const_iterator i = ls.begin();
|
||||
for (std::list<string>const_iterator i = ls.begin();
|
||||
i != ls.end(); ++i)
|
||||
{
|
||||
std::cerr << ':' << (*i) << ":\n";
|
||||
@ -226,8 +233,9 @@
|
||||
<A HREF="stringtok_std_h.txt">Another version of stringtok is given
|
||||
here</A>, suggested by Chris King and tweaked by Petr Prikryl,
|
||||
and this one uses the
|
||||
transformation functions given below. If you are comfortable with
|
||||
reading the new function names, this version is recommended as an example.
|
||||
transformation functions mentioned below. If you are comfortable
|
||||
with reading the new function names, this version is recommended
|
||||
as an example.
|
||||
</P>
|
||||
<P>Return <A HREF="#top">to top of page</A> or
|
||||
<A HREF="../faq/index.html">to the FAQ</A>.
|
||||
@ -240,30 +248,45 @@
|
||||
to all upper case." The word transformations is especially
|
||||
apt, because the standard template function
|
||||
<TT>transform<></TT> is used.
|
||||
</P>
|
||||
<P>This code will go through some iterations (no pun). Here's the
|
||||
simplistic version usually seen on Usenet:
|
||||
<PRE>
|
||||
#include <string>
|
||||
#include <algorithm>
|
||||
#include <cctype> // old <ctype.h>
|
||||
std::string s ("Some Kind Of Initial Input Goes Here");
|
||||
|
||||
// Change everything into upper case
|
||||
std::transform (s.begin(), s.end(), s.begin(), toupper);
|
||||
|
||||
// Change everything into lower case
|
||||
std::transform (s.begin(), s.end(), s.begin(), tolower);
|
||||
|
||||
// Change everything back into upper case, but store the
|
||||
// result in a different string
|
||||
std::string capital_s;
|
||||
capital_s.reserve(s.size());
|
||||
std::transform (s.begin(), s.end(), capital_s.begin(), tolower); </PRE>
|
||||
#include <string>
|
||||
#include <algorithm>
|
||||
#include <cctype> // old <ctype.h>
|
||||
|
||||
std::string s ("Some Kind Of Initial Input Goes Here");
|
||||
|
||||
// Change everything into upper case
|
||||
std::transform (s.begin(), s.end(), s.begin(), toupper);
|
||||
|
||||
// Change everything into lower case
|
||||
std::transform (s.begin(), s.end(), s.begin(), tolower);
|
||||
|
||||
// Change everything back into upper case, but store the
|
||||
// result in a different string
|
||||
std::string capital_s;
|
||||
capital_s.reserve(s.size());
|
||||
std::transform (s.begin(), s.end(), capital_s.begin(), tolower); </PRE>
|
||||
<SPAN CLASS="larger"><B>Note</B></SPAN> that these calls all involve
|
||||
the global C locale through the use of the C functions
|
||||
<TT>toupper/tolower</TT>. This is absolutely guaranteed to work --
|
||||
but only if you're using English text (bummer). A much better and
|
||||
more portable solution is to use a facet for a particular locale
|
||||
and call its conversion functions. (These are discussed more in
|
||||
Chapter 22.)
|
||||
but <EM>only</EM> if the string contains <EM>only</EM> characters
|
||||
from the basic source character set, and there are <EM>only</EM>
|
||||
96 of those. Which means that not even all English text can be
|
||||
represented (certain British spellings, proper names, and so forth).
|
||||
So, if all your input forevermore consists of only those 96
|
||||
characters (hahahahahaha), then you're done.
|
||||
</P>
|
||||
<P>At minimum, you can write
|
||||
</P>
|
||||
<P>The correct method is to use a facet for a particular locale
|
||||
and call its conversion functions. These are discussed more in
|
||||
Chapter 22; the specific part is
|
||||
<A HREF="../22_locale/howto.html#5">here</A>, which shows the
|
||||
final version of this code. (Thanks to James Kanze for assistance
|
||||
and suggestions on all of this.)
|
||||
</P>
|
||||
<P>Another common operation is trimming off excess whitespace. Much
|
||||
like transformations, this task is trivial with the use of string's
|
||||
@ -297,7 +320,7 @@
|
||||
Comments and suggestions are welcome, and may be sent to
|
||||
<A HREF="mailto:pme@sources.redhat.com">Phil Edwards</A> or
|
||||
<A HREF="mailto:gdr@egcs.cygnus.com">Gabriel Dos Reis</A>.
|
||||
<BR> $Id: howto.html,v 1.2 2000/07/07 21:13:28 pme Exp $
|
||||
<BR> $Id: howto.html,v 1.3 2000/07/11 21:45:07 pme Exp $
|
||||
</EM></P>
|
||||
|
||||
|
||||
|
||||
@ -9,7 +9,7 @@
|
||||
<TITLE>libstdc++-v3 HOWTO: Chapter 22</TITLE>
|
||||
<LINK REL="home" HREF="http://sources.redhat.com/libstdc++/docs/22_locale/">
|
||||
<LINK REL=StyleSheet HREF="../lib3styles.css">
|
||||
<!-- $Id: howto.html,v 1.3 2000/08/25 08:52:56 bkoz Exp $ -->
|
||||
<!-- $Id: howto.html,v 1.4 2000/08/31 01:17:53 bkoz Exp $ -->
|
||||
</HEAD>
|
||||
<BODY>
|
||||
|
||||
@ -27,6 +27,7 @@
|
||||
<LI><A HREF="#2">Nathan Myers on Locales</A>
|
||||
<LI><A HREF="#3">codecvt</A>
|
||||
<LI><A HREF="#4">ctype</A>
|
||||
<LI><A HREF="#5">Correct Transformations</A>
|
||||
</UL>
|
||||
|
||||
<HR>
|
||||
@ -41,6 +42,14 @@
|
||||
Programming Language (3rd Edition)</A>. It is a detailed
|
||||
description of locales and how to use them.
|
||||
</P>
|
||||
<P>He also writes:
|
||||
<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>
|
||||
</P>
|
||||
<P>Return <A HREF="#top">to top of page</A> or
|
||||
<A HREF="../faq/index.html">to the FAQ</A>.
|
||||
</P>
|
||||
@ -92,6 +101,114 @@ functionality are given.
|
||||
<A HREF="../faq/index.html">to the FAQ</A>.
|
||||
</P>
|
||||
|
||||
<HR>
|
||||
<H2><A NAME="5">Correct Transformations</A></H2>
|
||||
<!-- Jumping directly 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
|
||||
<TT> extern "Danish" int tolower (int); </TT>.
|
||||
</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:
|
||||
<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>
|
||||
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 <TT>toupper/tolower</TT> 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:
|
||||
<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) { return std::toupper(c,loc); }
|
||||
private:
|
||||
std::locale const& loc;
|
||||
};
|
||||
|
||||
struct Tolower
|
||||
{
|
||||
Tolower (std::locale const& l) : loc(l) {;}
|
||||
char operator() (char c) { 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("C") );
|
||||
Tolower down ( std::locale("C") );
|
||||
|
||||
// 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>
|
||||
<P>The final version of the code uses <TT>bind2nd</TT> 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>
|
||||
<P>Return <A HREF="#top">to top of page</A> or
|
||||
<A HREF="../faq/index.html">to the FAQ</A>.
|
||||
</P>
|
||||
|
||||
|
||||
|
||||
|
||||
<!-- ####################################################### -->
|
||||
@ -101,7 +218,7 @@ functionality are given.
|
||||
Comments and suggestions are welcome, and may be sent to
|
||||
<A HREF="mailto:pme@sources.redhat.com">Phil Edwards</A> or
|
||||
<A HREF="mailto:gdr@egcs.cygnus.com">Gabriel Dos Reis</A>.
|
||||
<BR> $Id: howto.html,v 1.3 2000/08/25 08:52:56 bkoz Exp $
|
||||
<BR> $Id: howto.html,v 1.4 2000/08/31 01:17:53 bkoz Exp $
|
||||
</EM></P>
|
||||
|
||||
|
||||
|
||||
@ -92,12 +92,13 @@
|
||||
|
||||
<P>We'd also like to thank the folks who have contributed time and
|
||||
energy in testing libstdc++-v3, especially those sending in testsuite
|
||||
evaluations:
|
||||
evaluations and documentation corrections:
|
||||
|
||||
<UL>
|
||||
|
||||
<LI>Levente Farkas
|
||||
<LI>Jürgen Freyh
|
||||
<LI>James Kanze
|
||||
<LI>llewelly <!-- Honest, that's the only name in the messages. -->
|
||||
<LI>Loren James Rittle
|
||||
<LI>George Talbot
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user