https://gcc.gnu.org/g:597ca24445462f11aaa3f7164a81f2f4f74bb80a
commit r15-7992-g597ca24445462f11aaa3f7164a81f2f4f74bb80a
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Wed Mar 12 11:30:04 2025 +0000
libstdc++: Add lambda example to case transformation docs
libstdc++-v3/ChangeLog:
* doc/xml/manual/strings.xml: Tweak formatting. Add example
using lambda.
* doc/html/manual/strings.html: Regenerate.
Diff:
---
libstdc++-v3/doc/html/manual/strings.html | 19 ++++++++++++++-----
libstdc++-v3/doc/xml/manual/strings.xml | 19 +++++++++++++++----
2 files changed, 29 insertions(+), 9 deletions(-)
diff --git a/libstdc++-v3/doc/html/manual/strings.html
b/libstdc++-v3/doc/html/manual/strings.html
index 34a34dfa980c..5344d0e89238 100644
--- a/libstdc++-v3/doc/html/manual/strings.html
+++ b/libstdc++-v3/doc/html/manual/strings.html
@@ -50,10 +50,12 @@
</pre><p>
<span class="emphasis"><em>Note</em></span> that these calls all
involve the global C locale through the use of the C functions
- <code class="code">toupper/tolower</code>. This is absolutely
guaranteed to work --
- but <span class="emphasis"><em>only</em></span> if the string contains
<span class="emphasis"><em>only</em></span> characters
- from the basic source character set, and there are <span
class="emphasis"><em>only</em></span>
- 96 of those. Which means that not even all English text can be
+ <code class="code">toupper</code>/<code class="code">tolower</code>.
+ This is absolutely guaranteed to work
+ -- but <span class="emphasis"><em>only</em></span> if the string contains
+ <span class="emphasis"><em>only</em></span> characters from the basic
source character set,
+ and there are <span class="emphasis"><em>only</em></span> 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.
@@ -73,7 +75,14 @@
// std::tolower(c) is undefined if c < 0 so cast to unsigned char.
return std::tolower((unsigned char)c);
} </pre><p>(Thanks to James Kanze for assistance and suggestions on all of
this.)
- </p><p>Another common operation is trimming off excess whitespace. Much
+ </p><p>
+ Since C++11 the wrapper can be replaced with a lambda expression,
+ which can perform the conversion to <code class="code">unsigned
char</code> and
+ also ensure the single-argument form of <code
class="code">std::lower</code> is used:
+ </p><pre class="programlisting">
+ std::transform (s.begin(), s.end(), capital_s.begin(),
+ [](unsigned char c) { return std::tolower(c); });
+ </pre><p>Another common operation is trimming off excess whitespace. Much
like transformations, this task is trivial with the use of string's
<code class="code">find</code> family. These examples are broken into
multiple
statements for readability:
diff --git a/libstdc++-v3/doc/xml/manual/strings.xml
b/libstdc++-v3/doc/xml/manual/strings.xml
index 4a63dd964771..58a78d01d239 100644
--- a/libstdc++-v3/doc/xml/manual/strings.xml
+++ b/libstdc++-v3/doc/xml/manual/strings.xml
@@ -66,10 +66,12 @@
<para>
<emphasis>Note</emphasis> that these calls all
involve the global C locale through the use of the C functions
- <code>toupper/tolower</code>. This is absolutely guaranteed to work --
- but <emphasis>only</emphasis> if the string contains
<emphasis>only</emphasis> characters
- from the basic source character set, and there are
<emphasis>only</emphasis>
- 96 of those. Which means that not even all English text can be
+ <code>toupper</code>/<code>tolower</code>.
+ This is absolutely guaranteed to work
+ -- but <emphasis>only</emphasis> if the string contains
+ <emphasis>only</emphasis> characters from the basic source character set,
+ and there are <emphasis>only</emphasis> 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.
@@ -93,6 +95,15 @@
} </programlisting>
<para>(Thanks to James Kanze for assistance and suggestions on all of this.)
</para>
+ <para>
+ Since C++11 the wrapper can be replaced with a lambda expression,
+ which can perform the conversion to <code>unsigned char</code> and
+ also ensure the single-argument form of <code>std::lower</code> is used:
+ </para>
+ <programlisting>
+ std::transform (s.begin(), s.end(), capital_s.begin(),
+ [](unsigned char c) { return std::tolower(c); });
+ </programlisting>
<para>Another common operation is trimming off excess whitespace. Much
like transformations, this task is trivial with the use of string's
<code>find</code> family. These examples are broken into multiple
