Release 1.53.0

[SVN r82734]
Merge string_ref doc changes to release
2025-10-17 18:55:20 +02:00 · 2013-02-04 18:11:49 +00:00 · 2013-01-14 16:34:16 +00:00 · 2012-12-17 14:36:31 +00:00 · 2012-12-11 16:41:54 +00:00 · 2012-10-03 23:09:58 +00:00
13 changed files with 1890 additions and 127 deletions
--- a/doc/Jamfile.v2
+++ b/doc/Jamfile.v2
@@ -43,7 +43,7 @@ using quickbook ;
 path-constant boost-images : ../../../doc/src/images ;

 xml declval : declval.qbk ;
-boostbook standalone
+boostbook standalone_declval
    :
        declval
    :
@@ -62,7 +62,22 @@ boostbook standalone
        
     ;

+xml string_ref : string_ref.qbk ;
+boostbook standalone_string_ref
+    :
+        string_ref
+    :
+        # File name of HTML output:
+        <xsl:param>root.filename=string_ref
+        # How far down we chunk nested sections, basically all of them:
+        <xsl:param>chunk.section.depth=0
+        # Don't put the first section on the same page as the TOC:
+        <xsl:param>chunk.first.sections=0
+        # How far down sections get TOC's
+        <xsl:param>toc.section.depth=1
+        # Max depth in each TOC:
+        <xsl:param>toc.max.depth=1
+        # How far down we go with TOC's
+        <xsl:param>generate.section.toc.level=1

-
-
-
+     ;
--- a/doc/html/string_ref.html
+++ b/doc/html/string_ref.html
@@ -0,0 +1,280 @@
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
+<title>String_Ref</title>
+<link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css">
+<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
+<link rel="home" href="string_ref.html" title="String_Ref">
+</head>
+<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
+<table cellpadding="2" width="100%"><tr>
+<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../boost.png"></td>
+<td align="center"><a href="../../../../index.html">Home</a></td>
+<td align="center"><a href="../../../../libs/libraries.htm">Libraries</a></td>
+<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
+<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
+<td align="center"><a href="../../../../more/index.htm">More</a></td>
+</tr></table>
+<hr>
+<div class="spirit-nav"></div>
+<div class="article">
+<div class="titlepage">
+<div>
+<div><h2 class="title">
+<a name="string_ref"></a>String_Ref</h2></div>
+<div><div class="authorgroup"><div class="author"><h3 class="author">
+<span class="firstname">Marshall</span> <span class="surname">Clow</span>
+</h3></div></div></div>
+<div><p class="copyright">Copyright &#169; 2012 Marshall Clow</p></div>
+<div><div class="legalnotice">
+<a name="string_ref.legal"></a><p>
+        Distributed under the Boost Software License, Version 1.0. (See accompanying
+        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
+      </p>
+</div></div>
+</div>
+<hr>
+</div>
+<div class="toc">
+<p><b>Table of Contents</b></p>
+<dl>
+<dt><span class="section"><a href="string_ref.html#string_ref.overview">Overview</a></span></dt>
+<dt><span class="section"><a href="string_ref.html#string_ref.examples">Examples</a></span></dt>
+<dt><span class="section"><a href="string_ref.html#string_ref.reference">Reference </a></span></dt>
+<dt><span class="section"><a href="string_ref.html#string_ref.history">History</a></span></dt>
+</dl>
+</div>
+<div class="section string_ref_overview">
+<div class="titlepage"><div><div><h2 class="title" style="clear: both">
+<a name="string_ref.overview"></a><a class="link" href="string_ref.html#string_ref.overview" title="Overview">Overview</a>
+</h2></div></div></div>
+<p>
+      Boost.StringRef is an implementation of Jeffrey Yaskin's <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3442.html" target="_top">N3442:
+      string_ref: a non-owning reference to a string</a>.
+    </p>
+<p>
+      When you are parsing/processing strings from some external source, frequently
+      you want to pass a piece of text to a procedure for specialized processing.
+      The canonical way to do this is as a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code>,
+      but that has certain drawbacks:
+    </p>
+<p>
+      1) If you are processing a buffer of text (say a HTTP response or the contents
+      of a file), then you have to create the string from the text you want to pass,
+      which involves memory allocation and copying of data.
+    </p>
+<p>
+      2) if a routine receives a constant <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code>
+      and wants to pass a portion of that string to another routine, then it must
+      create a new string of that substring.
+    </p>
+<p>
+      3) A routine receives a constant <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code>
+      and wants to return a portion of the string, then it must create a new string
+      to return.
+    </p>
+<p>
+      <code class="computeroutput"><span class="identifier">string_ref</span></code> is designed to solve
+      these efficiency problems. A <code class="computeroutput"><span class="identifier">string_ref</span></code>
+      is a read-only reference to a contiguous sequence of characters, and provides
+      much of the functionality of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code>.
+      A <code class="computeroutput"><span class="identifier">string_ref</span></code> is cheap to create,
+      copy and pass by value, because it does not actually own the storage that it
+      points to.
+    </p>
+<p>
+      A <code class="computeroutput"><span class="identifier">string_ref</span></code> is implemented
+      as a small struct that contains a pointer to the start of the character data
+      and a count. A <code class="computeroutput"><span class="identifier">string_ref</span></code> is
+      cheap to create and cheap to copy.
+    </p>
+<p>
+      <code class="computeroutput"><span class="identifier">string_ref</span></code> acts as a container;
+      it includes all the methods that you would expect in a container, including
+      iteration support, <code class="computeroutput"><span class="keyword">operator</span> <span class="special">[]</span></code>,
+      <code class="computeroutput"><span class="identifier">at</span></code> and <code class="computeroutput"><span class="identifier">size</span></code>.
+      It can be used with any of the iterator-based algorithms in the STL - as long
+      as you don't need to change the underlying data (<code class="computeroutput"><span class="identifier">sort</span></code>
+      and <code class="computeroutput"><span class="identifier">remove</span></code>, for example, will
+      not work)
+    </p>
+<p>
+      Besides generic container functionality, <code class="computeroutput"><span class="identifier">string_ref</span></code>
+      provides a subset of the interface of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code>.
+      This makes it easy to replace parameters of type <code class="computeroutput"><span class="keyword">const</span>
+      <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">&amp;</span></code>
+      with <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">string_ref</span></code>. Like <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code>,
+      <code class="computeroutput"><span class="identifier">string_ref</span></code> has a static member
+      variable named <code class="computeroutput"><span class="identifier">npos</span></code> to denote
+      the result of failed searches, and to mean "the end".
+    </p>
+<p>
+      Because a <code class="computeroutput"><span class="identifier">string_ref</span></code> does not
+      own the data that it "points to", it introduces lifetime issues into
+      code that uses it. The programmer must ensure that the data that a <code class="computeroutput"><span class="identifier">string_ref</span></code> refers to exists as long as the
+      <code class="computeroutput"><span class="identifier">string_ref</span></code> does.
+    </p>
+</div>
+<div class="section string_ref_examples">
+<div class="titlepage"><div><div><h2 class="title" style="clear: both">
+<a name="string_ref.examples"></a><a class="link" href="string_ref.html#string_ref.examples" title="Examples">Examples</a>
+</h2></div></div></div>
+<p>
+      Integrating <code class="computeroutput"><span class="identifier">string_ref</span></code> into
+      your code is fairly simple. Wherever you pass a <code class="computeroutput"><span class="keyword">const</span>
+      <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">&amp;</span></code>
+      or <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code> as a parameter, that's a candidate
+      for passing a <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">string_ref</span></code>.
+    </p>
+<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">extract_part</span> <span class="special">(</span> <span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">&amp;</span><span class="identifier">bar</span> <span class="special">)</span> <span class="special">{</span>
+    <span class="keyword">return</span> <span class="identifier">bar</span><span class="special">.</span><span class="identifier">substr</span> <span class="special">(</span> <span class="number">2</span><span class="special">,</span> <span class="number">3</span> <span class="special">);</span>
+    <span class="special">}</span>
+
+<span class="keyword">if</span> <span class="special">(</span> <span class="identifier">extract_part</span> <span class="special">(</span> <span class="string">"ABCDEFG"</span> <span class="special">).</span><span class="identifier">front</span><span class="special">()</span> <span class="special">==</span> <span class="string">"C"</span> <span class="special">)</span> <span class="special">{</span> <span class="comment">/* do something */</span> <span class="special">}</span>
+</pre>
+<p>
+      Let's figure out what happens in this (contrived) example.
+    </p>
+<p>
+      First, a temporary string is created from the string literal <code class="computeroutput"><span class="string">"ABCDEFG"</span></code>, and it is passed (by reference)
+      to the routine <code class="computeroutput"><span class="identifier">extract_part</span></code>.
+      Then a second string is created in the call <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">::</span><span class="identifier">substr</span></code>
+      and returned to <code class="computeroutput"><span class="identifier">extract_part</span></code>
+      (this copy may be elided by RVO). Then <code class="computeroutput"><span class="identifier">extract_part</span></code>
+      returns that string back to the caller (again this copy may be elided). The
+      first temporary string is deallocated, and <code class="computeroutput"><span class="identifier">front</span></code>
+      is called on the second string, and then it is deallocated as well.
+    </p>
+<p>
+      Two <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code>s are created, and two copy operations.
+      That's (potentially) four memory allocations and deallocations, and the associated
+      copying of data.
+    </p>
+<p>
+      Now let's look at the same code with <code class="computeroutput"><span class="identifier">string_ref</span></code>:
+    </p>
+<pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">string_ref</span> <span class="identifier">extract_part</span> <span class="special">(</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">string_ref</span> <span class="identifier">bar</span> <span class="special">)</span> <span class="special">{</span>
+    <span class="keyword">return</span> <span class="identifier">bar</span><span class="special">.</span><span class="identifier">substr</span> <span class="special">(</span> <span class="number">2</span><span class="special">,</span> <span class="number">3</span> <span class="special">);</span>
+    <span class="special">}</span>
+
+<span class="keyword">if</span> <span class="special">(</span> <span class="identifier">extract_part</span> <span class="special">(</span> <span class="string">"ABCDEFG"</span> <span class="special">).</span><span class="identifier">front</span><span class="special">()</span> <span class="special">==</span> <span class="string">"C"</span> <span class="special">)</span> <span class="special">{</span> <span class="comment">/* do something */</span> <span class="special">}</span>
+</pre>
+<p>
+      No memory allocations. No copying of character data. No changes to the code
+      other than the types. There are two <code class="computeroutput"><span class="identifier">string_ref</span></code>s
+      created, and two <code class="computeroutput"><span class="identifier">string_ref</span></code>s
+      copied, but those are cheap operations.
+    </p>
+</div>
+<div class="section string_ref_reference">
+<div class="titlepage"><div><div><h2 class="title" style="clear: both">
+<a name="string_ref.reference"></a><a class="link" href="string_ref.html#string_ref.reference" title="Reference">Reference </a>
+</h2></div></div></div>
+<p>
+      The header file "string_ref.hpp" defines a template <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">basic_string_ref</span></code>,
+      and four specializations - for <code class="computeroutput"><span class="keyword">char</span></code>
+      / <code class="computeroutput"><span class="keyword">wchar_t</span></code> / <code class="computeroutput"><span class="identifier">char16_t</span></code>
+      / <code class="computeroutput"><span class="identifier">char32_t</span></code> .
+    </p>
+<p>
+      <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">utility</span><span class="special">/</span><span class="identifier">string_ref</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
+    </p>
+<p>
+      Construction and copying:
+    </p>
+<pre class="programlisting"><span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">basic_string_ref</span> <span class="special">();</span>    <span class="comment">// Constructs an empty string_ref</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">basic_string_ref</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">charT</span><span class="special">*</span> <span class="identifier">str</span><span class="special">);</span> <span class="comment">// Constructs from a NULL-terminated string</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">basic_string_ref</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">charT</span><span class="special">*</span> <span class="identifier">str</span><span class="special">,</span> <span class="identifier">size_type</span> <span class="identifier">len</span><span class="special">);</span> <span class="comment">// Constructs from a pointer, length pair</span>
+<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Allocator</span><span class="special">&gt;</span>
+<span class="identifier">basic_string_ref</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_string</span><span class="special">&lt;</span><span class="identifier">charT</span><span class="special">,</span> <span class="identifier">traits</span><span class="special">,</span> <span class="identifier">Allocator</span><span class="special">&gt;&amp;</span> <span class="identifier">str</span><span class="special">);</span> <span class="comment">// Constructs from a std::string</span>
+<span class="identifier">basic_string_ref</span> <span class="special">(</span><span class="keyword">const</span> <span class="identifier">basic_string_ref</span> <span class="special">&amp;</span><span class="identifier">rhs</span><span class="special">);</span>
+<span class="identifier">basic_string_ref</span><span class="special">&amp;</span> <span class="keyword">operator</span><span class="special">=(</span><span class="keyword">const</span> <span class="identifier">basic_string_ref</span> <span class="special">&amp;</span><span class="identifier">rhs</span><span class="special">);</span>
+</pre>
+<p>
+      <code class="computeroutput"><span class="identifier">string_ref</span></code> does not define
+      a move constructor nor a move-assignment operator because copying a <code class="computeroutput"><span class="identifier">string_ref</span></code> is just a cheap as moving one.
+    </p>
+<p>
+      Basic container-like functions:
+    </p>
+<pre class="programlisting"><span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">size_type</span> <span class="identifier">size</span><span class="special">()</span>     <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">size_type</span> <span class="identifier">length</span><span class="special">()</span>   <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">size_type</span> <span class="identifier">max_size</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="keyword">bool</span> <span class="identifier">empty</span><span class="special">()</span>         <span class="keyword">const</span> <span class="special">;</span>
+
+<span class="comment">// All iterators are const_iterators</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">const_iterator</span>  <span class="identifier">begin</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">const_iterator</span> <span class="identifier">cbegin</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">const_iterator</span>    <span class="identifier">end</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">const_iterator</span>   <span class="identifier">cend</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">const_reverse_iterator</span>         <span class="identifier">rbegin</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">const_reverse_iterator</span>        <span class="identifier">crbegin</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">const_reverse_iterator</span>           <span class="identifier">rend</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">const_reverse_iterator</span>          <span class="identifier">crend</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span>
+</pre>
+<p>
+      Access to the individual elements (all of which are const):
+    </p>
+<pre class="programlisting"><span class="identifier">BOOST_CONSTEXPR</span> <span class="keyword">const</span> <span class="identifier">charT</span><span class="special">&amp;</span> <span class="keyword">operator</span><span class="special">[](</span><span class="identifier">size_type</span> <span class="identifier">pos</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="keyword">const</span> <span class="identifier">charT</span><span class="special">&amp;</span> <span class="identifier">at</span><span class="special">(</span><span class="identifier">size_t</span> <span class="identifier">pos</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="keyword">const</span> <span class="identifier">charT</span><span class="special">&amp;</span> <span class="identifier">front</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="keyword">const</span> <span class="identifier">charT</span><span class="special">&amp;</span> <span class="identifier">back</span><span class="special">()</span>  <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">BOOST_CONSTEXPR</span> <span class="keyword">const</span> <span class="identifier">charT</span><span class="special">*</span> <span class="identifier">data</span><span class="special">()</span>  <span class="keyword">const</span> <span class="special">;</span>
+</pre>
+<p>
+      Modifying the <code class="computeroutput"><span class="identifier">string_ref</span></code> (but
+      not the underlying data):
+    </p>
+<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">clear</span><span class="special">();</span>
+<span class="keyword">void</span> <span class="identifier">remove_prefix</span><span class="special">(</span><span class="identifier">size_type</span> <span class="identifier">n</span><span class="special">);</span>
+<span class="keyword">void</span> <span class="identifier">remove_suffix</span><span class="special">(</span><span class="identifier">size_type</span> <span class="identifier">n</span><span class="special">);</span>
+</pre>
+<p>
+      Searching:
+    </p>
+<pre class="programlisting"><span class="identifier">size_type</span> <span class="identifier">find</span><span class="special">(</span><span class="identifier">basic_string_ref</span> <span class="identifier">s</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">size_type</span> <span class="identifier">find</span><span class="special">(</span><span class="identifier">charT</span> <span class="identifier">c</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">size_type</span> <span class="identifier">rfind</span><span class="special">(</span><span class="identifier">basic_string_ref</span> <span class="identifier">s</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">size_type</span> <span class="identifier">rfind</span><span class="special">(</span><span class="identifier">charT</span> <span class="identifier">c</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">size_type</span> <span class="identifier">find_first_of</span><span class="special">(</span><span class="identifier">charT</span> <span class="identifier">c</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">size_type</span> <span class="identifier">find_last_of</span> <span class="special">(</span><span class="identifier">charT</span> <span class="identifier">c</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+
+<span class="identifier">size_type</span> <span class="identifier">find_first_of</span><span class="special">(</span><span class="identifier">basic_string_ref</span> <span class="identifier">s</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">size_type</span> <span class="identifier">find_last_of</span><span class="special">(</span><span class="identifier">basic_string_ref</span> <span class="identifier">s</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">size_type</span> <span class="identifier">find_first_not_of</span><span class="special">(</span><span class="identifier">basic_string_ref</span> <span class="identifier">s</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">size_type</span> <span class="identifier">find_first_not_of</span><span class="special">(</span><span class="identifier">charT</span> <span class="identifier">c</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">size_type</span> <span class="identifier">find_last_not_of</span><span class="special">(</span><span class="identifier">basic_string_ref</span> <span class="identifier">s</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="identifier">size_type</span> <span class="identifier">find_last_not_of</span><span class="special">(</span><span class="identifier">charT</span> <span class="identifier">c</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+</pre>
+<p>
+      String-like operations:
+    </p>
+<pre class="programlisting"><span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">basic_string_ref</span> <span class="identifier">substr</span><span class="special">(</span><span class="identifier">size_type</span> <span class="identifier">pos</span><span class="special">,</span> <span class="identifier">size_type</span> <span class="identifier">n</span><span class="special">=</span><span class="identifier">npos</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span> <span class="comment">// Creates a new string_ref</span>
+<span class="keyword">bool</span> <span class="identifier">starts_with</span><span class="special">(</span><span class="identifier">charT</span> <span class="identifier">c</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="keyword">bool</span> <span class="identifier">starts_with</span><span class="special">(</span><span class="identifier">basic_string_ref</span> <span class="identifier">x</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="keyword">bool</span> <span class="identifier">ends_with</span><span class="special">(</span><span class="identifier">charT</span> <span class="identifier">c</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+<span class="keyword">bool</span> <span class="identifier">ends_with</span><span class="special">(</span><span class="identifier">basic_string_ref</span> <span class="identifier">x</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span>
+</pre>
+</div>
+<div class="section string_ref_history">
+<div class="titlepage"><div><div><h2 class="title" style="clear: both">
+<a name="string_ref.history"></a><a class="link" href="string_ref.html#string_ref.history" title="History">History</a>
+</h2></div></div></div>
+<h4>
+<a name="string_ref.history.h0"></a>
+      <span><a name="string_ref.history.boost_1_53"></a></span><a class="link" href="string_ref.html#string_ref.history.boost_1_53">boost
+      1.53</a>
+    </h4>
+<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
+          Introduced
+        </li></ul></div>
+</div>
+</div>
+<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
+<td align="left"><p><small>Last revised: January 14, 2013 at 16:24:14 GMT</small></p></td>
+<td align="right"><div class="copyright-footer"></div></td>
+</tr></table>
+<hr>
+<div class="spirit-nav"></div>
+</body>
+</html>
--- a/doc/string_ref.qbk
+++ b/doc/string_ref.qbk
@@ -0,0 +1,167 @@
+[/
+ / Copyright (c) 2012 Marshall Clow
+ /
+ / Distributed under the Boost Software License, Version 1.0. (See accompanying
+ / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ /]
+
+[article String_Ref
+    [quickbook 1.5]
+    [authors [Clow, Marshall]]
+    [copyright 2012 Marshall Clow]
+    [license
+        Distributed under the Boost Software License, Version 1.0.
+        (See accompanying file LICENSE_1_0.txt or copy at
+        [@http://www.boost.org/LICENSE_1_0.txt])
+    ]
+]
+
+[/===============]
+[section Overview]
+[/===============]
+
+Boost.StringRef is an implementation of Jeffrey Yaskin's [@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3442.html N3442:
+string_ref: a non-owning reference to a string]. 
+
+When you are parsing/processing strings from some external source, frequently you want to pass a piece of text to a procedure for specialized processing. The canonical way to do this is as a `std::string`, but that has certain drawbacks:
+
+1) If you are processing a buffer of text (say a HTTP response or the contents of a file), then you have to create the string from the text you want to pass, which involves memory allocation and copying of data.
+
+2) if a routine receives a constant `std::string` and wants to pass a portion of that string to another routine, then it must create a new string of that substring.
+
+3) A routine receives a constant `std::string` and wants to return a portion of the string, then it must create a new string to return.
+
+`string_ref` is designed to solve these efficiency problems. A `string_ref` is a read-only reference to a contiguous sequence of characters, and provides much of the functionality of `std::string`. A `string_ref` is cheap to create, copy and pass by value, because it does not actually own the storage that it points to. 
+
+A `string_ref` is implemented as a small struct that contains a pointer to the start of the character data and a count. A `string_ref` is cheap to create and cheap to copy.
+
+`string_ref` acts as a container; it includes all the methods that you would expect in a container, including iteration support, `operator []`, `at` and `size`. It can be used with any of the iterator-based algorithms in the STL - as long as you don't need to change the underlying data (`sort` and `remove`, for example, will not work)
+
+Besides generic container functionality, `string_ref` provides a subset of the interface of `std::string`. This makes it easy to replace parameters of type `const std::string &` with `boost::string_ref`. Like `std::string`, `string_ref` has a static member variable named `npos` to denote the result of failed searches, and to mean "the end".
+
+Because a `string_ref` does not own the data that it "points to", it introduces lifetime issues into code that uses it. The programmer must ensure that the data that a `string_ref` refers to exists as long as the `string_ref` does.
+
+[endsect]
+
+
+[/===============]
+[section Examples]
+[/===============]
+
+Integrating `string_ref` into your code is fairly simple. Wherever you pass a `const std::string &` or `std::string` as a parameter, that's a candidate for passing a `boost::string_ref`.
+
+    std::string extract_part ( const std::string &bar ) {
+        return bar.substr ( 2, 3 );
+        }
+        
+    if ( extract_part ( "ABCDEFG" ).front() == "C" ) { /* do something */ }
+    
+Let's figure out what happens in this (contrived) example.
+
+First, a temporary string is created from the string literal `"ABCDEFG"`, and it is passed (by reference) to the routine `extract_part`. Then a second string is created in the call `std::string::substr` and returned to `extract_part` (this copy may be elided by RVO). Then `extract_part` returns that string back to the caller (again this copy may be elided). The first temporary string is deallocated, and `front` is called on the second string, and then it is deallocated as well.
+
+Two `std::string`s are created, and two copy operations. That's (potentially) four memory allocations and deallocations, and the associated copying of data.
+
+Now let's look at the same code with `string_ref`:
+
+    boost::string_ref extract_part ( boost::string_ref bar ) {
+        return bar.substr ( 2, 3 );
+        }
+        
+    if ( extract_part ( "ABCDEFG" ).front() == "C" ) { /* do something */ }
+
+No memory allocations. No copying of character data. No changes to the code other than the types. There are two `string_ref`s created, and two `string_ref`s copied, but those are cheap operations.
+
+[endsect]
+
+
+[/=================]
+[section:reference Reference ]
+[/=================]
+
+The header file "string_ref.hpp" defines a template `boost::basic_string_ref`, and four specializations - for `char` / `wchar_t` / `char16_t` / `char32_t` .
+
+`#include <boost/utility/string_ref.hpp>`
+
+Construction and copying:
+
+    BOOST_CONSTEXPR basic_string_ref ();    // Constructs an empty string_ref
+    BOOST_CONSTEXPR basic_string_ref(const charT* str); // Constructs from a NULL-terminated string
+    BOOST_CONSTEXPR basic_string_ref(const charT* str, size_type len); // Constructs from a pointer, length pair
+    template<typename Allocator>
+    basic_string_ref(const std::basic_string<charT, traits, Allocator>& str); // Constructs from a std::string
+    basic_string_ref (const basic_string_ref &rhs);
+    basic_string_ref& operator=(const basic_string_ref &rhs);
+
+`string_ref` does not define a move constructor nor a move-assignment operator because copying a `string_ref` is just a cheap as moving one.
+
+Basic container-like functions:
+
+    BOOST_CONSTEXPR size_type size()     const ;
+    BOOST_CONSTEXPR size_type length()   const ;
+    BOOST_CONSTEXPR size_type max_size() const ;
+    BOOST_CONSTEXPR bool empty()         const ;
+    
+    // All iterators are const_iterators
+    BOOST_CONSTEXPR const_iterator  begin() const ;
+    BOOST_CONSTEXPR const_iterator cbegin() const ;
+    BOOST_CONSTEXPR const_iterator    end() const ;
+    BOOST_CONSTEXPR const_iterator   cend() const ;
+    const_reverse_iterator         rbegin() const ;
+    const_reverse_iterator        crbegin() const ;
+    const_reverse_iterator           rend() const ;
+    const_reverse_iterator          crend() const ;
+
+Access to the individual elements (all of which are const):
+
+    BOOST_CONSTEXPR const charT& operator[](size_type pos) const ;
+    const charT& at(size_t pos) const ;
+    BOOST_CONSTEXPR const charT& front() const ;
+    BOOST_CONSTEXPR const charT& back()  const ;
+    BOOST_CONSTEXPR const charT* data()  const ;
+
+Modifying the `string_ref` (but not the underlying data):
+
+    void clear();
+    void remove_prefix(size_type n);
+    void remove_suffix(size_type n);
+
+Searching:
+
+    size_type find(basic_string_ref s) const ;
+    size_type find(charT c) const ;
+    size_type rfind(basic_string_ref s) const ;
+    size_type rfind(charT c) const ;
+    size_type find_first_of(charT c) const ;
+    size_type find_last_of (charT c) const ;
+        
+    size_type find_first_of(basic_string_ref s) const ;
+    size_type find_last_of(basic_string_ref s) const ;
+    size_type find_first_not_of(basic_string_ref s) const ;
+    size_type find_first_not_of(charT c) const ;
+    size_type find_last_not_of(basic_string_ref s) const ;
+    size_type find_last_not_of(charT c) const ;
+
+String-like operations:
+
+    BOOST_CONSTEXPR basic_string_ref substr(size_type pos, size_type n=npos) const ; // Creates a new string_ref
+    bool starts_with(charT c) const ;
+    bool starts_with(basic_string_ref x) const ;
+    bool ends_with(charT c) const ;
+    bool ends_with(basic_string_ref x) const ;
+
+[endsect]
+
+[/===============]
+[section History]
+[/===============]
+
+[heading boost 1.53]
+* Introduced
+    
+
+[endsect]
+
+
+
+
--- a/include/boost/detail/call_traits.hpp
+++ b/include/boost/detail/call_traits.hpp
@@ -24,6 +24,7 @@
 #include <cstddef>

 #include <boost/type_traits/is_arithmetic.hpp>
+#include <boost/type_traits/is_enum.hpp>
 #include <boost/type_traits/is_pointer.hpp>
 #include <boost/detail/workaround.hpp>

@@ -43,20 +44,26 @@ struct ct_imp2<T, true>
   typedef const T param_type;
 };

-template <typename T, bool isp, bool b1>
+template <typename T, bool isp, bool b1, bool b2>
 struct ct_imp
 {
   typedef const T& param_type;
 };

-template <typename T, bool isp>
-struct ct_imp<T, isp, true>
+template <typename T, bool isp, bool b2>
+struct ct_imp<T, isp, true, b2>
 {
   typedef typename ct_imp2<T, sizeof(T) <= sizeof(void*)>::param_type param_type;
 };

-template <typename T, bool b1>
-struct ct_imp<T, true, b1>
+template <typename T, bool isp, bool b1>
+struct ct_imp<T, isp, b1, true>
+{
+   typedef typename ct_imp2<T, sizeof(T) <= sizeof(void*)>::param_type param_type;
+};
+
+template <typename T, bool b1, bool b2>
+struct ct_imp<T, true, b1, b2>
 {
   typedef const T param_type;
 };
@@ -79,7 +86,8 @@ public:
   typedef typename boost::detail::ct_imp<
      T,
      ::boost::is_pointer<T>::value,
-      ::boost::is_arithmetic<T>::value
+      ::boost::is_arithmetic<T>::value,
+      ::boost::is_enum<T>::value
   >::param_type param_type;
 };

--- a/include/boost/utility/detail/result_of_iterate.hpp
+++ b/include/boost/utility/detail/result_of_iterate.hpp
@@ -5,6 +5,11 @@
 //  1.0. (See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt)

+//  Copyright Daniel Walker, Eric Niebler, Michel Morin 2008-2012.
+//  Use, modification and distribution is subject to the Boost Software
+//  License, Version 1.0. (See accompanying file LICENSE_1_0.txt or
+//  copy at http://www.boost.org/LICENSE_1_0.txt)
+
 // For more information, see http://www.boost.org/libs/utility
 #if !defined(BOOST_PP_IS_ITERATING)
 # error Boost result_of - do not include this file!
@@ -18,31 +23,29 @@
 #endif

 #if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
-template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
-         BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
+template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
 struct tr1_result_of<F(BOOST_RESULT_OF_ARGS)>
    : mpl::if_<
          mpl::or_< is_pointer<F>, is_member_function_pointer<F> >
        , boost::detail::tr1_result_of_impl<
-            typename remove_cv<F>::type, 
-            typename remove_cv<F>::type(BOOST_RESULT_OF_ARGS), 
+            typename remove_cv<F>::type,
+            typename remove_cv<F>::type(BOOST_RESULT_OF_ARGS),
            (boost::detail::has_result_type<F>::value)>
        , boost::detail::tr1_result_of_impl<
            F,
-            F(BOOST_RESULT_OF_ARGS), 
+            F(BOOST_RESULT_OF_ARGS),
            (boost::detail::has_result_type<F>::value)> >::type { };
 #endif

-#if !defined(BOOST_NO_DECLTYPE) && defined(BOOST_RESULT_OF_USE_DECLTYPE)
+#ifdef BOOST_RESULT_OF_USE_DECLTYPE

 // Uses declval following N3225 20.7.7.6 when F is not a pointer.
-template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
-         BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
+template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
 struct result_of<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>
    : mpl::if_<
-          mpl::or_< is_pointer<F>, is_member_function_pointer<F> >
+          is_member_function_pointer<F>
        , detail::tr1_result_of_impl<
-            typename remove_cv<F>::type, 
+            typename remove_cv<F>::type,
            typename remove_cv<F>::type(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), false
          >
        , detail::cpp0x_result_of_impl<
@@ -53,53 +56,119 @@ struct result_of<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>

 namespace detail {

-template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
-         BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
-struct cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T))>
+#ifdef BOOST_NO_SFINAE_EXPR
+
+template<typename F>
+struct BOOST_PP_CAT(result_of_callable_fun_2_, BOOST_PP_ITERATION());
+
+template<typename R BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(), typename T)>
+struct BOOST_PP_CAT(result_of_callable_fun_2_, BOOST_PP_ITERATION())<R(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(), T))> {
+    R operator()(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(), T)) const;
+    typedef result_of_private_type const &(*pfn_t)(...);
+    operator pfn_t() const volatile;
+};
+
+template<typename F>
+struct BOOST_PP_CAT(result_of_callable_fun_, BOOST_PP_ITERATION());
+
+template<typename F>
+struct BOOST_PP_CAT(result_of_callable_fun_, BOOST_PP_ITERATION())<F *>
+  : BOOST_PP_CAT(result_of_callable_fun_2_, BOOST_PP_ITERATION())<F>
+{};
+
+template<typename F>
+struct BOOST_PP_CAT(result_of_callable_fun_, BOOST_PP_ITERATION())<F &>
+  : BOOST_PP_CAT(result_of_callable_fun_2_, BOOST_PP_ITERATION())<F>
+{};
+
+template<typename F>
+struct BOOST_PP_CAT(result_of_select_call_wrapper_type_, BOOST_PP_ITERATION())
+  : mpl::eval_if<
+        is_class<typename remove_reference<F>::type>,
+        result_of_wrap_callable_class<F>,
+        mpl::identity<BOOST_PP_CAT(result_of_callable_fun_, BOOST_PP_ITERATION())<typename remove_cv<F>::type> >
+    >
+{};
+
+template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(), typename T)>
+struct BOOST_PP_CAT(result_of_is_callable_, BOOST_PP_ITERATION()) {
+    typedef typename BOOST_PP_CAT(result_of_select_call_wrapper_type_, BOOST_PP_ITERATION())<F>::type wrapper_t;
+    static const bool value = (
+        sizeof(result_of_no_type) == sizeof(detail::result_of_is_private_type(
+            (boost::declval<wrapper_t>()(BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_ITERATION(), boost::declval<T, >() BOOST_PP_INTERCEPT)), result_of_weird_type())
+        ))
+    );
+    typedef mpl::bool_<value> type;
+};
+
+template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
+struct cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), true>
+    : lazy_enable_if<
+          BOOST_PP_CAT(result_of_is_callable_, BOOST_PP_ITERATION())<F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(), T)>
+        , cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), false>
+      >
+{};
+
+template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
+struct cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), false>
 {
  typedef decltype(
    boost::declval<F>()(
-      BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_ITERATION(), declval<T, >() BOOST_PP_INTERCEPT)
+      BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_ITERATION(), boost::declval<T, >() BOOST_PP_INTERCEPT)
    )
  ) type;
 };

-} // namespace detail 
+#else // BOOST_NO_SFINAE_EXPR

-#else // defined(BOOST_NO_DECLTYPE)
+template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
+struct cpp0x_result_of_impl<F(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)),
+                            typename result_of_always_void<decltype(
+                                boost::declval<F>()(
+                                    BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_ITERATION(), boost::declval<T, >() BOOST_PP_INTERCEPT)
+                                )
+                            )>::type> {
+  typedef decltype(
+    boost::declval<F>()(
+      BOOST_PP_ENUM_BINARY_PARAMS(BOOST_PP_ITERATION(), boost::declval<T, >() BOOST_PP_INTERCEPT)
+    )
+  ) type;
+};
+
+#endif // BOOST_NO_SFINAE_EXPR
+
+} // namespace detail
+
+#else // defined(BOOST_RESULT_OF_USE_DECLTYPE)

 #if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
-template<typename F BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
-         BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
+template<typename F BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
 struct result_of<F(BOOST_RESULT_OF_ARGS)>
    : tr1_result_of<F(BOOST_RESULT_OF_ARGS)> { };
 #endif

-#endif // defined(BOOST_NO_DECLTYPE)
+#endif // defined(BOOST_RESULT_OF_USE_DECLTYPE)

 #undef BOOST_RESULT_OF_ARGS

-#if BOOST_PP_ITERATION() >= 1 
+#if BOOST_PP_ITERATION() >= 1

 namespace detail {

-template<typename R,  typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
-         BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
+template<typename R,  typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
 struct tr1_result_of_impl<R (*)(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), FArgs, false>
 {
  typedef R type;
 };

-template<typename R,  typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
-         BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
+template<typename R,  typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
 struct tr1_result_of_impl<R (&)(BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),T)), FArgs, false>
 {
  typedef R type;
 };

 #if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
-template<typename R, typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
-         BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
+template<typename R, typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
 struct tr1_result_of_impl<R (T0::*)
                     (BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_PP_ITERATION(),T)),
                 FArgs, false>
@@ -107,8 +176,7 @@ struct tr1_result_of_impl<R (T0::*)
  typedef R type;
 };

-template<typename R, typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
-         BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
+template<typename R, typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
 struct tr1_result_of_impl<R (T0::*)
                     (BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_PP_ITERATION(),T))
                     const,
@@ -117,8 +185,7 @@ struct tr1_result_of_impl<R (T0::*)
  typedef R type;
 };

-template<typename R, typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
-         BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
+template<typename R, typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
 struct tr1_result_of_impl<R (T0::*)
                     (BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_PP_ITERATION(),T))
                     volatile,
@@ -127,8 +194,7 @@ struct tr1_result_of_impl<R (T0::*)
  typedef R type;
 };

-template<typename R, typename FArgs BOOST_PP_COMMA_IF(BOOST_PP_ITERATION())
-         BOOST_PP_ENUM_PARAMS(BOOST_PP_ITERATION(),typename T)>
+template<typename R, typename FArgs BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_ITERATION(),typename T)>
 struct tr1_result_of_impl<R (T0::*)
                     (BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_PP_ITERATION(),T))
                     const volatile,
--- a/include/boost/utility/result_of.hpp
+++ b/include/boost/utility/result_of.hpp
@@ -10,24 +10,48 @@
 #define BOOST_RESULT_OF_HPP

 #include <boost/config.hpp>
-#include <boost/preprocessor/iteration/iterate.hpp> 
-#include <boost/preprocessor/punctuation/comma_if.hpp> 
-#include <boost/preprocessor/repetition/enum_params.hpp> 
-#include <boost/preprocessor/repetition/enum_binary_params.hpp> 
-#include <boost/preprocessor/repetition/enum_shifted_params.hpp> 
-#include <boost/preprocessor/facilities/intercept.hpp> 
+#include <boost/preprocessor/cat.hpp>
+#include <boost/preprocessor/iteration/iterate.hpp>
+#include <boost/preprocessor/repetition/enum_params.hpp>
+#include <boost/preprocessor/repetition/enum_trailing_params.hpp>
+#include <boost/preprocessor/repetition/enum_binary_params.hpp>
+#include <boost/preprocessor/repetition/enum_shifted_params.hpp>
+#include <boost/preprocessor/facilities/intercept.hpp>
 #include <boost/detail/workaround.hpp>
 #include <boost/mpl/has_xxx.hpp>
 #include <boost/mpl/if.hpp>
+#include <boost/mpl/eval_if.hpp>
 #include <boost/mpl/bool.hpp>
+#include <boost/mpl/identity.hpp>
 #include <boost/mpl/or.hpp>
+#include <boost/type_traits/is_class.hpp>
 #include <boost/type_traits/is_pointer.hpp>
 #include <boost/type_traits/is_member_function_pointer.hpp>
 #include <boost/type_traits/remove_cv.hpp>
+#include <boost/type_traits/remove_reference.hpp>
 #include <boost/utility/declval.hpp>
+#include <boost/utility/enable_if.hpp>

 #ifndef BOOST_RESULT_OF_NUM_ARGS
-#  define BOOST_RESULT_OF_NUM_ARGS 10
+#  define BOOST_RESULT_OF_NUM_ARGS 16
+#endif
+
+// Use the decltype-based version of result_of by default if the compiler
+// supports N3276 <http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2011/n3276.pdf>.
+// The user can force the choice by defining either BOOST_RESULT_OF_USE_DECLTYPE or
+// BOOST_RESULT_OF_USE_TR1, but not both!
+#if defined(BOOST_RESULT_OF_USE_DECLTYPE) && defined(BOOST_RESULT_OF_USE_TR1)
+#  error Both BOOST_RESULT_OF_USE_DECLTYPE and BOOST_RESULT_OF_USE_TR1 cannot be defined at the same time.
+#endif
+
+#ifndef BOOST_RESULT_OF_USE_TR1
+#  ifndef BOOST_RESULT_OF_USE_DECLTYPE
+#    ifndef BOOST_NO_CXX11_DECLTYPE_N3276 // this implies !defined(BOOST_NO_CXX11_DECLTYPE)
+#      define BOOST_RESULT_OF_USE_DECLTYPE
+#    else
+#      define BOOST_RESULT_OF_USE_TR1
+#    endif
+#  endif
 #endif

 namespace boost {
@@ -41,7 +65,67 @@ namespace detail {
 BOOST_MPL_HAS_XXX_TRAIT_DEF(result_type)

 template<typename F, typename FArgs, bool HasResultType> struct tr1_result_of_impl;
-template<typename F> struct cpp0x_result_of_impl;
+
+#ifdef BOOST_NO_SFINAE_EXPR
+
+struct result_of_private_type {};
+
+struct result_of_weird_type {
+  friend result_of_private_type operator,(result_of_private_type, result_of_weird_type);
+};
+
+typedef char result_of_yes_type;      // sizeof(result_of_yes_type) == 1
+typedef char (&result_of_no_type)[2]; // sizeof(result_of_no_type)  == 2
+
+template<typename T>
+result_of_no_type result_of_is_private_type(T const &);
+result_of_yes_type result_of_is_private_type(result_of_private_type);
+
+template<typename C>
+struct result_of_callable_class : C {
+    result_of_callable_class();
+    typedef result_of_private_type const &(*pfn_t)(...);
+    operator pfn_t() const volatile;
+};
+
+template<typename C>
+struct result_of_wrap_callable_class {
+  typedef result_of_callable_class<C> type;
+};
+
+template<typename C>
+struct result_of_wrap_callable_class<C const> {
+  typedef result_of_callable_class<C> const type;
+};
+
+template<typename C>
+struct result_of_wrap_callable_class<C volatile> {
+  typedef result_of_callable_class<C> volatile type;
+};
+
+template<typename C>
+struct result_of_wrap_callable_class<C const volatile> {
+  typedef result_of_callable_class<C> const volatile type;
+};
+
+template<typename C>
+struct result_of_wrap_callable_class<C &> {
+  typedef typename result_of_wrap_callable_class<C>::type &type;
+};
+
+template<typename F, bool TestCallability = true> struct cpp0x_result_of_impl;
+
+#else // BOOST_NO_SFINAE_EXPR
+
+template<typename T>
+struct result_of_always_void
+{
+  typedef void type;
+};
+
+template<typename F, typename Enable = void> struct cpp0x_result_of_impl {};
+
+#endif // BOOST_NO_SFINAE_EXPR

 template<typename F>
 struct result_of_void_impl
--- a/include/boost/utility/string_ref.hpp
+++ b/include/boost/utility/string_ref.hpp
@@ -0,0 +1,386 @@
+/* 
+   Copyright (c) Marshall Clow 2012-2012.
+
+   Distributed under the Boost Software License, Version 1.0. (See accompanying
+   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+    For more information, see http://www.boost.org
+    
+    Based on the StringRef implementation in LLVM (http://llvm.org) and
+    N3422 by Jeffrey Yasskin
+        http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3442.html
+
+*/
+
+#ifndef BOOST_STRING_REF_HPP
+#define BOOST_STRING_REF_HPP
+
+#include <boost/config.hpp>
+#include <boost/detail/workaround.hpp>
+
+#include <stdexcept>
+#include <algorithm>
+#include <functional>
+#include <string>
+
+namespace boost {
+    
+    namespace detail {
+    //  A helper functor because sometimes we don't have lambdas
+        template <typename charT, typename traits>
+        class string_ref_traits_eq {
+        public:
+            string_ref_traits_eq ( charT ch ) : ch_(ch) {}
+            bool operator () ( charT val ) const { return traits::eq ( ch_, val ); }
+            charT ch_;
+            };
+        }
+    
+    template<typename charT, typename traits> class basic_string_ref;
+    typedef basic_string_ref<char,     std::char_traits<char> >        string_ref;
+    typedef basic_string_ref<wchar_t,  std::char_traits<wchar_t> >    wstring_ref;
+
+#ifndef BOOST_NO_CXX11_CHAR16_T
+    typedef basic_string_ref<char16_t, std::char_traits<char16_t> > u16string_ref;
+#endif
+
+#ifndef BOOST_NO_CXX11_CHAR32_T
+    typedef basic_string_ref<char32_t, std::char_traits<char32_t> > u32string_ref;
+#endif
+    
+    template<typename charT, typename traits>
+    class basic_string_ref {
+    public:
+        // types
+        typedef charT value_type;
+        typedef const charT* pointer;
+        typedef const charT& reference;
+        typedef const charT& const_reference;
+        typedef pointer const_iterator; // impl-defined
+        typedef const_iterator iterator;
+        typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+        typedef const_reverse_iterator reverse_iterator;
+        typedef std::size_t size_type;
+        typedef ptrdiff_t difference_type;
+        static BOOST_CONSTEXPR_OR_CONST size_type npos = size_type(-1);
+        
+        // construct/copy
+        BOOST_CONSTEXPR basic_string_ref ()
+            : ptr_(NULL), len_(0) {}
+
+        BOOST_CONSTEXPR basic_string_ref (const basic_string_ref &rhs)
+            : ptr_(rhs.ptr_), len_(rhs.len_) {}
+
+        basic_string_ref& operator=(const basic_string_ref &rhs) {
+            ptr_ = rhs.ptr_;
+            len_ = rhs.len_;
+            return *this;
+            }
+            
+        basic_string_ref(const charT* str)
+            : ptr_(str), len_(traits::length(str)) {}
+
+        template<typename Allocator>
+        basic_string_ref(const std::basic_string<charT, traits, Allocator>& str)
+            : ptr_(str.data()), len_(str.length()) {}
+
+        BOOST_CONSTEXPR basic_string_ref(const charT* str, size_type len)
+            : ptr_(str), len_(len) {}
+
+#ifndef BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
+        template<typename Allocator>
+        explicit operator std::basic_string<charT, traits, Allocator>() const {
+            return std::basic_string<charT, traits, Allocator> ( ptr_, len_ );
+            }
+#endif
+        
+        // iterators
+        BOOST_CONSTEXPR const_iterator   begin() const { return ptr_; }
+        BOOST_CONSTEXPR const_iterator  cbegin() const { return ptr_; }
+        BOOST_CONSTEXPR const_iterator     end() const { return ptr_ + len_; }
+        BOOST_CONSTEXPR const_iterator    cend() const { return ptr_ + len_; }
+                const_reverse_iterator  rbegin() const { return const_reverse_iterator (end()); }
+                const_reverse_iterator crbegin() const { return const_reverse_iterator (end()); }
+                const_reverse_iterator    rend() const { return const_reverse_iterator (begin()); }
+                const_reverse_iterator   crend() const { return const_reverse_iterator (begin()); }
+        
+        // capacity
+        BOOST_CONSTEXPR size_type size()     const { return len_; }
+        BOOST_CONSTEXPR size_type length()   const { return len_; }
+        BOOST_CONSTEXPR size_type max_size() const { return len_; }
+        BOOST_CONSTEXPR bool empty()         const { return len_ == 0; }
+        
+        // element access
+        BOOST_CONSTEXPR const charT& operator[](size_type pos) const { return ptr_[pos]; }
+
+        const charT& at(size_t pos) const {
+            if ( pos >= len_ )
+                throw std::out_of_range ( "boost::string_ref::at" );
+            return ptr_[pos];
+            }
+            
+        BOOST_CONSTEXPR const charT& front() const { return ptr_[0]; }
+        BOOST_CONSTEXPR const charT& back()  const { return ptr_[len_-1]; }
+        BOOST_CONSTEXPR const charT* data()  const { return ptr_; }
+        
+        // modifiers
+        void clear() { len_ = 0; }
+        void remove_prefix(size_type n) {
+            if ( n > len_ )
+                n = len_;
+            ptr_ += n;
+            len_ -= n;
+            }
+            
+        void remove_suffix(size_type n) {
+            if ( n > len_ )
+                n = len_;
+            len_ -= n;
+            }
+            
+        
+        // basic_string_ref string operations
+        BOOST_CONSTEXPR
+        basic_string_ref substr(size_type pos, size_type n=npos) const {
+#if BOOST_WORKAROUND(BOOST_MSVC, <= 1600)
+            // Looks like msvc 8 and 9 have a codegen bug when one branch of
+            // a conditional operator is a throw expression. -EAN 2012/12/04
+            if ( pos > size()) throw std::out_of_range ( "string_ref::substr" );
+            if ( n == npos || pos + n > size()) n = size () - pos;
+            return basic_string_ref ( data() + pos, n );
+#else
+            return pos > size() ? throw std::out_of_range ( "string_ref::substr" ) :
+                basic_string_ref ( data() + pos, n == npos || pos + n > size() ? size() - pos : n );
+#endif
+            }
+        
+        int compare(basic_string_ref x) const {
+            int cmp = traits::compare ( ptr_, x.ptr_, (std::min)(len_, x.len_));
+            return cmp != 0 ? cmp : ( len_ == x.len_ ? 0 : len_ < x.len_ ? -1 : 1 );
+            }
+        
+        bool starts_with(charT c) const { return !empty() && traits::eq ( c, front()); }
+        bool starts_with(basic_string_ref x) const {
+            return len_ >= x.len_ && traits::compare ( ptr_, x.ptr_, x.len_ ) == 0;
+            }
+        
+        bool ends_with(charT c) const { return !empty() && traits::eq ( c, back()); }
+        bool ends_with(basic_string_ref x) const {
+            return len_ >= x.len_ && traits::compare ( ptr_ + len_ - x.len_, x.ptr_, x.len_ ) == 0;
+            }
+
+        size_type find(basic_string_ref s) const {
+            const_iterator iter = std::search ( this->cbegin (), this->cend (), 
+                                                s.cbegin (), s.cend (), traits::eq );
+            return iter = this->cend () ? npos : std::distance ( this->cbegin (), iter );
+            }
+        
+        size_type find(charT c) const {
+            const_iterator iter = std::find_if ( this->cbegin (), this->cend (), 
+                                    detail::string_ref_traits_eq<charT, traits> ( c ));
+            return iter == this->cend () ? npos : std::distance ( this->cbegin (), iter );
+            }
+                        
+        size_type rfind(basic_string_ref s) const {
+            const_reverse_iterator iter = std::search ( this->crbegin (), this->crend (), 
+                                                s.crbegin (), s.crend (), traits::eq );
+            return iter == this->crend () ? npos : reverse_distance ( this->crbegin (), iter );
+            }
+
+        size_type rfind(charT c) const {
+            const_reverse_iterator iter = std::find_if ( this->crbegin (), this->crend (), 
+                                    detail::string_ref_traits_eq<charT, traits> ( c ));
+            return iter == this->crend () ? npos : reverse_distance ( this->crbegin (), iter );
+            }
+        
+        size_type find_first_of(charT c) const { return  find (c); }
+        size_type find_last_of (charT c) const { return rfind (c); }
+        
+        size_type find_first_of(basic_string_ref s) const {
+            const_iterator iter = std::find_first_of 
+            	( this->cbegin (), this->cend (), s.cbegin (), s.cend (), traits::eq );
+            return iter == this->cend () ? npos : std::distance ( this->cbegin (), iter );
+            }
+        
+        size_type find_last_of(basic_string_ref s) const {
+            const_reverse_iterator iter = std::find_first_of 
+                ( this->crbegin (), this->crend (), s.cbegin (), s.cend (), traits::eq );
+            return iter == this->crend () ? npos : reverse_distance ( this->crbegin (), iter);
+            }
+        
+        size_type find_first_not_of(basic_string_ref s) const {
+        	const_iterator iter = find_not_of ( this->cbegin (), this->cend (), s );
+            return iter == this->cend () ? npos : std::distance ( this->cbegin (), iter );
+            }
+        
+        size_type find_first_not_of(charT c) const {
+            for ( const_iterator iter = this->cbegin (); iter != this->cend (); ++iter )
+                if ( !traits::eq ( c, *iter ))
+                    return std::distance ( this->cbegin (), iter );
+            return npos;
+            }
+        
+        size_type find_last_not_of(basic_string_ref s) const {
+        	const_reverse_iterator iter = find_not_of ( this->crbegin (), this->crend (), s );
+            return iter == this->crend () ? npos : reverse_distance ( this->crbegin (), iter );
+            }
+        
+        size_type find_last_not_of(charT c) const {
+            for ( const_reverse_iterator iter = this->crbegin (); iter != this->crend (); ++iter )
+                if ( !traits::eq ( c, *iter ))
+                    return reverse_distance ( this->crbegin (), iter );
+            return npos;
+            }
+
+    private:
+        template <typename r_iter>
+        size_type reverse_distance ( r_iter first, r_iter last ) const {
+            return len_ - 1 - std::distance ( first, last );
+            }
+        
+        template <typename Iterator>
+        Iterator find_not_of ( Iterator first, Iterator last, basic_string_ref s ) const {
+			for ( ; first != last ; ++first )
+				if ( 0 == traits::find ( s.ptr_, s.len_, *first ))
+					return first;
+			return last;
+			}
+		
+       		
+        
+        const charT *ptr_;
+        std::size_t len_;
+        };
+    
+    // Comparison operators
+    template<typename charT, typename traits>
+    bool operator==(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        if ( x.size () != y.size ()) return false;
+        return x.compare(y) == 0;
+        }
+    
+    template<typename charT, typename traits>
+    bool operator!=(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        if ( x.size () != y.size ()) return true;
+        return x.compare(y) != 0;
+        }
+
+    template<typename charT, typename traits>
+    bool operator<(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        return x.compare(y) < 0;
+        }
+
+    template<typename charT, typename traits>
+    bool operator>(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        return x.compare(y) > 0;
+        }
+
+    template<typename charT, typename traits>
+    bool operator<=(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        return x.compare(y) <= 0;
+        }
+
+    template<typename charT, typename traits>
+    bool operator>=(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        return x.compare(y) >= 0;
+        }
+
+    
+    // Inserter
+    template<class charT, class traits>
+    std::basic_ostream<charT, traits>&
+    operator<<(std::basic_ostream<charT, traits>& os, const basic_string_ref<charT,traits>& str) {
+#ifdef BOOST_NO_CXX11_RANGE_BASED_FOR
+        for ( typename basic_string_ref<charT, traits>::const_iterator iter = str.begin (); iter != str.end (); ++iter )
+            os << *iter;
+#else
+        for ( charT x : str )
+            os << x;
+#endif
+        return os;
+        }
+    
+#if 0
+    // numeric conversions
+    //
+    //  These are short-term implementations.
+    //  In a production environment, I would rather avoid the copying.
+    //
+    int stoi (string_ref str, size_t* idx=0, int base=10) {
+        return std::stoi ( std::string(str), idx, base );
+        }
+    
+    long stol (string_ref str, size_t* idx=0, int base=10) {
+        return std::stol ( std::string(str), idx, base );
+        }
+        
+    unsigned long stoul (string_ref str, size_t* idx=0, int base=10) {
+        return std::stoul ( std::string(str), idx, base );
+        }
+        
+    long long stoll (string_ref str, size_t* idx=0, int base=10) {
+        return std::stoll ( std::string(str), idx, base );
+        }
+    
+    unsigned long long stoull (string_ref str, size_t* idx=0, int base=10) {
+        return std::stoull ( std::string(str), idx, base );
+        }
+    
+    float stof (string_ref str, size_t* idx=0) {
+        return std::stof ( std::string(str), idx );
+        }
+        
+    double stod (string_ref str, size_t* idx=0) {
+        return std::stod ( std::string(str), idx );
+        }
+        
+    long double stold (string_ref str, size_t* idx=0)  {
+        return std::stold ( std::string(str), idx );
+        }
+    
+    int  stoi (wstring_ref str, size_t* idx=0, int base=10) {
+        return std::stoi ( std::wstring(str), idx, base );
+        }
+        
+    long stol (wstring_ref str, size_t* idx=0, int base=10) {
+        return std::stol ( std::wstring(str), idx, base );
+        }
+        
+    unsigned long stoul (wstring_ref str, size_t* idx=0, int base=10) {
+        return std::stoul ( std::wstring(str), idx, base );
+        }
+        
+    long long stoll (wstring_ref str, size_t* idx=0, int base=10) {
+        return std::stoll ( std::wstring(str), idx, base );
+        }
+        
+    unsigned long long stoull (wstring_ref str, size_t* idx=0, int base=10) {
+        return std::stoull ( std::wstring(str), idx, base );
+        }
+    
+    float  stof (wstring_ref str, size_t* idx=0) {
+        return std::stof ( std::wstring(str), idx );
+        }
+        
+    double stod (wstring_ref str, size_t* idx=0) {
+        return std::stod ( std::wstring(str), idx );
+        }
+        
+    long double stold (wstring_ref str, size_t* idx=0) {
+        return std::stold ( std::wstring(str), idx );
+        }
+#endif
+
+}
+
+#if 0
+namespace std {
+    // Hashing
+    template<> struct hash<boost::string_ref>;
+    template<> struct hash<boost::u16string_ref>;
+    template<> struct hash<boost::u32string_ref>;
+    template<> struct hash<boost::wstring_ref>;
+}
+#endif
+
+#endif
--- a/index.html
+++ b/index.html
@@ -28,7 +28,9 @@
 				<a href="swap.html">swap</a><br>
 				<a href="throw_exception.html">throw_exception</a><br>
 				<a href="utility.htm">utility</a><br>
-                <a href="value_init.htm">value_init</a></p>
+            <a href="doc/html/string_ref.html">string_ref</a><br>
+            <a href="value_init.htm">value_init</a>
+         </p>
 		</blockquote>
 		<hr>
 		<p>&copy; Copyright Beman Dawes, 2001</p>
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -31,6 +31,8 @@ test-suite utility
        [ run ../ref_test.cpp ../../test/build//boost_test_exec_monitor/<link>static ]
        [ compile result_of_test.cpp ]
        [ run ../shared_iterator_test.cpp ]
+        [ run string_ref_test1.cpp ]
+        [ run string_ref_test2.cpp ]
        [ run ../value_init_test.cpp ]
        [ run ../value_init_workaround_test.cpp ]
        [ run ../initialized_test.cpp ]
--- a/test/result_of_test.cpp
+++ b/test/result_of_test.cpp
@@ -5,7 +5,7 @@
 //  1.0. (See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt)

-#define BOOST_RESULT_OF_USE_DECLTYPE
+#include <boost/config.hpp>

 // For more information, see http://www.boost.org/libs/utility
 #include <boost/utility/result_of.hpp>
@@ -62,6 +62,9 @@ struct int_result_type_and_float_result_of_and_char_return_template
  char operator()(char);
 };

+template<typename T>
+struct cv_overload_check {};
+
 struct result_of_member_function_template
 {
  template<typename F> struct result;
@@ -69,13 +72,13 @@ struct result_of_member_function_template
  template<typename This, typename That> struct result<This(That)> { typedef That type; };
  template<class T> typename result<result_of_member_function_template(T)>::type operator()(T);

-  template<typename This, typename That> struct result<const This(That)> { typedef const That type; };
+  template<typename This, typename That> struct result<const This(That)> { typedef cv_overload_check<const That> type; };
  template<class T> typename result<const result_of_member_function_template(T)>::type operator()(T) const;

-  template<typename This, typename That> struct result<volatile This(That)> { typedef volatile That type; };
+  template<typename This, typename That> struct result<volatile This(That)> { typedef cv_overload_check<volatile That> type; };
  template<class T> typename result<volatile result_of_member_function_template(T)>::type operator()(T) volatile;

-  template<typename This, typename That> struct result<const volatile This(That)> { typedef const volatile That type; };
+  template<typename This, typename That> struct result<const volatile This(That)> { typedef cv_overload_check<const volatile That> type; };
  template<class T> typename result<const volatile result_of_member_function_template(T)>::type operator()(T) const volatile;

  template<typename This, typename That> struct result<This(That &, That)> { typedef That & type; };
@@ -91,14 +94,17 @@ struct result_of_member_function_template
  template<class T> typename result<result_of_member_function_template(T const volatile &, T)>::type operator()(T const volatile &, T);
 };

-struct no_result_type_or_result_of
+struct no_result_type_or_result
 {
-  int operator()(double);
-  short operator()(double) const;
-  unsigned int operator()();
-  unsigned short operator()() volatile;
-  const unsigned short operator()() const volatile;
-#if !defined(BOOST_NO_RVALUE_REFERENCES)
+  short operator()(double);
+  cv_overload_check<const short> operator()(double) const;
+  cv_overload_check<volatile short> operator()(double) volatile;
+  cv_overload_check<const volatile short> operator()(double) const volatile;
+  int operator()();
+  cv_overload_check<const int> operator()() const;
+  cv_overload_check<volatile int> operator()() volatile;
+  cv_overload_check<const volatile int> operator()() const volatile;
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
  short operator()(int&&);
  int operator()(int&);
  long operator()(int const&);
@@ -106,20 +112,44 @@ struct no_result_type_or_result_of
 };

 template<typename T>
-struct no_result_type_or_result_of_template
+struct no_result_type_or_result_template
 {
-  int operator()(double);
-  short operator()(double) const;
-  unsigned int operator()();
-  unsigned short operator()() volatile;
-  const unsigned short operator()() const volatile;
-#if !defined(BOOST_NO_RVALUE_REFERENCES)
+  short operator()(double);
+  cv_overload_check<const short> operator()(double) const;
+  cv_overload_check<volatile short> operator()(double) volatile;
+  cv_overload_check<const volatile short> operator()(double) const volatile;
+  int operator()();
+  cv_overload_check<const int> operator()() const;
+  cv_overload_check<volatile int> operator()() volatile;
+  cv_overload_check<const volatile int> operator()() const volatile;
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
  short operator()(int&&);
  int operator()(int&);
  long operator()(int const&);
 #endif
 };

+// sfinae_tests are derived from example code from Joel de Guzman,
+// which demonstrated the interaction between result_of and SFINAE.
+template <typename F, typename Arg>
+typename boost::result_of<F(Arg const&)>::type
+sfinae_test(F f, Arg const& arg)
+{
+    return f(arg);
+}
+
+template <typename F, typename Arg>
+typename boost::result_of<F(Arg&)>::type
+sfinae_test(F f, Arg& arg)
+{
+    return f(arg);
+}
+
+int sfinae_test_f(int& i)
+{
+    return i;
+}
+
 struct X {};

 int main()
@@ -130,6 +160,10 @@ int main()
  typedef int (&func_ref)(float, double);
  typedef int (*func_ptr_0)();
  typedef int (&func_ref_0)();
+  typedef void (*func_ptr_void)(float, double);
+  typedef void (&func_ref_void)(float, double);
+  typedef void (*func_ptr_void_0)();
+  typedef void (&func_ref_void_0)();
  typedef int (X::*mem_func_ptr)(float);
  typedef int (X::*mem_func_ptr_c)(float) const;
  typedef int (X::*mem_func_ptr_v)(float) volatile;
@@ -157,7 +191,7 @@ int main()

  // Prior to decltype, result_of could not deduce the return type
  // nullary function objects unless they exposed a result_type.
-#if !defined(BOOST_NO_DECLTYPE)
+#if defined(BOOST_RESULT_OF_USE_DECLTYPE)
  BOOST_STATIC_ASSERT((is_same<result_of<int_result_of(void)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of(void)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<int_result_of_template<void>(void)>::type, int>::value));
@@ -169,14 +203,11 @@ int main()
  BOOST_STATIC_ASSERT((is_same<result_of<volatile int_result_of_template<void>(void)>::type, void>::value));
 #endif

-  BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_type_and_float_result_of_and_char_return(char)>::type, int>::value));
-  BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_type_and_float_result_of_and_char_return_template<void>(char)>::type, int>::value));
-
  // Prior to decltype, result_of ignored a nested result<> if
  // result_type was defined. After decltype, result_of deduces the
  // actual return type of the function object, ignoring both
  // result<> and result_type.
-#if !defined(BOOST_NO_DECLTYPE)
+#if defined(BOOST_RESULT_OF_USE_DECLTYPE)
  BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return(char)>::type, char>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return_template<void>(char)>::type, char>::value));
 #else
@@ -184,41 +215,52 @@ int main()
  BOOST_STATIC_ASSERT((is_same<result_of<int_result_type_and_float_result_of_and_char_return_template<void>(char)>::type, int>::value));
 #endif

+  BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_type_and_float_result_of_and_char_return(char)>::type, int>::value));
+  BOOST_STATIC_ASSERT((is_same<tr1_result_of<int_result_type_and_float_result_of_and_char_return_template<void>(char)>::type, int>::value));
+
  BOOST_STATIC_ASSERT((is_same<result_of<func_ptr(char, float)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<func_ref(char, float)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<func_ptr_0()>::type, int>::value)); 
  BOOST_STATIC_ASSERT((is_same<result_of<func_ref_0()>::type, int>::value)); 
+  BOOST_STATIC_ASSERT((is_same<result_of<func_ptr_void(char, float)>::type, void>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<func_ref_void(char, float)>::type, void>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<func_ptr_void_0()>::type, void>::value)); 
+  BOOST_STATIC_ASSERT((is_same<result_of<func_ref_void_0()>::type, void>::value)); 
  BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr(X,char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_c(X,char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_v(X,char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_cv(X,char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<mem_func_ptr_0(X)>::type, int>::value)); 
-  BOOST_STATIC_ASSERT((is_same<result_of<func_ptr(void)>::type, int>::value));

  BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ptr(char, float)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ref(char, float)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ptr_0()>::type, int>::value)); 
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ref_0()>::type, int>::value)); 
+  BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ptr_void(char, float)>::type, void>::value));
+  BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ref_void(char, float)>::type, void>::value));
+  BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ptr_void_0()>::type, void>::value)); 
+  BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ref_void_0()>::type, void>::value)); 
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<mem_func_ptr(X,char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<mem_func_ptr_c(X,char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<mem_func_ptr_v(X,char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<mem_func_ptr_cv(X,char)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<mem_func_ptr_0(X)>::type, int>::value)); 
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ptr(void)>::type, int>::value));
+  BOOST_STATIC_ASSERT((is_same<tr1_result_of<func_ref(void)>::type, int>::value));

  BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(double)>::type, double>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<const result_of_member_function_template(double)>::type, const double>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<volatile result_of_member_function_template(double)>::type, volatile double>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<const volatile result_of_member_function_template(double)>::type, const volatile double>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<const result_of_member_function_template(double)>::type, cv_overload_check<const double> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<volatile result_of_member_function_template(double)>::type, cv_overload_check<volatile double> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<const volatile result_of_member_function_template(double)>::type, cv_overload_check<const volatile double> >::value));
  BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int &, int)>::type, int &>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int const &, int)>::type, int const &>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int volatile &, int)>::type, int volatile &>::value));
  BOOST_STATIC_ASSERT((is_same<result_of<result_of_member_function_template(int const volatile &, int)>::type, int const volatile &>::value));

  BOOST_STATIC_ASSERT((is_same<tr1_result_of<result_of_member_function_template(double)>::type, double>::value));
-  BOOST_STATIC_ASSERT((is_same<tr1_result_of<const result_of_member_function_template(double)>::type, const double>::value));
-  BOOST_STATIC_ASSERT((is_same<tr1_result_of<volatile result_of_member_function_template(double)>::type, volatile double>::value));
-  BOOST_STATIC_ASSERT((is_same<tr1_result_of<const volatile result_of_member_function_template(double)>::type, const volatile double>::value));
+  BOOST_STATIC_ASSERT((is_same<tr1_result_of<const result_of_member_function_template(double)>::type, cv_overload_check<const double> >::value));
+  BOOST_STATIC_ASSERT((is_same<tr1_result_of<volatile result_of_member_function_template(double)>::type, cv_overload_check<volatile double> >::value));
+  BOOST_STATIC_ASSERT((is_same<tr1_result_of<const volatile result_of_member_function_template(double)>::type, cv_overload_check<const volatile double> >::value));
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<result_of_member_function_template(int &, int)>::type, int &>::value));
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<result_of_member_function_template(int const &, int)>::type, int const &>::value));
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<result_of_member_function_template(int volatile &, int)>::type, int volatile &>::value));
@@ -231,26 +273,38 @@ int main()
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<pf_t(int)>::type, int>::value));
  BOOST_STATIC_ASSERT((is_same<tr1_result_of<pf_t const(int)>::type,int>::value));

-#if !defined(BOOST_NO_DECLTYPE)
-  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(double)>::type, int>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(void)>::type, unsigned int>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result_of(double)>::type, short>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result_of(void)>::type, unsigned short>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result_of(void)>::type, const unsigned short>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(double)>::type, int>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(void)>::type, unsigned int>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result_of_template<void>(double)>::type, short>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result_of_template<void>(void)>::type, unsigned short>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result_of_template<void>(void)>::type, const unsigned short>::value));
-#if !defined(BOOST_NO_RVALUE_REFERENCES)
-  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(int&&)>::type, short>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(int&)>::type, int>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of(int const&)>::type, long>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(int&&)>::type, short>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(int&)>::type, int>::value));
-  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_of_template<void>(int const&)>::type, long>::value));
+#if defined(BOOST_RESULT_OF_USE_DECLTYPE)
+  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result(double)>::type, short>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result(double)>::type, cv_overload_check<const short> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result(double)>::type, cv_overload_check<volatile short> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result(double)>::type, cv_overload_check<const volatile short> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result(void)>::type, int>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result(void)>::type, cv_overload_check<const int> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result(void)>::type, cv_overload_check<volatile int> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result(void)>::type, cv_overload_check<const volatile int> >::value));
+
+  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_template<void>(double)>::type, short>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result_template<void>(double)>::type, cv_overload_check<const short> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result_template<void>(double)>::type, cv_overload_check<volatile short> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result_template<void>(double)>::type, cv_overload_check<const volatile short> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_template<void>(void)>::type, int>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<const no_result_type_or_result_template<void>(void)>::type, cv_overload_check<const int> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<volatile no_result_type_or_result_template<void>(void)>::type, cv_overload_check<volatile int> >::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<const volatile no_result_type_or_result_template<void>(void)>::type, cv_overload_check<const volatile int> >::value));
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result(int&&)>::type, short>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result(int&)>::type, int>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result(int const&)>::type, long>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_template<void>(int&&)>::type, short>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_template<void>(int&)>::type, int>::value));
+  BOOST_STATIC_ASSERT((is_same<result_of<no_result_type_or_result_template<void>(int const&)>::type, long>::value));
 #endif
 #endif

+#if defined(BOOST_RESULT_OF_USE_DECLTYPE)
+  int i = 123;
+  sfinae_test(sfinae_test_f, i);
+#endif // defined(BOOST_RESULT_OF_USE_DECLTYPE)
+
  return 0;
 }
--- a/test/string_ref_test1.cpp
+++ b/test/string_ref_test1.cpp
@@ -0,0 +1,111 @@
+/* 
+   Copyright (c) Marshall Clow 2012-2012.
+
+   Distributed under the Boost Software License, Version 1.0. (See accompanying
+   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+    For more information, see http://www.boost.org
+*/
+
+#include <iostream>
+#include <algorithm>
+#include <string>
+
+#include <boost/utility/string_ref.hpp>
+
+
+#include <boost/test/included/test_exec_monitor.hpp>
+
+typedef boost::string_ref string_ref;
+
+//  Should be equal
+void interop ( const std::string &str, string_ref ref ) {
+//  BOOST_CHECK ( str == ref );
+    BOOST_CHECK ( str.size () == ref.size ());
+    BOOST_CHECK ( std::equal ( str.begin (),  str.end (),  ref.begin ()));
+    BOOST_CHECK ( std::equal ( str.rbegin (), str.rend (), ref.rbegin ()));
+    }
+
+void null_tests ( const char *p ) {
+//  All zero-length string-refs should be equal
+    string_ref sr1; // NULL, 0
+    string_ref sr2 ( NULL, 0 );
+    string_ref sr3 ( p, 0 );
+    string_ref sr4 ( p );
+    sr4.clear ();
+    
+    BOOST_CHECK ( sr1 == sr2 );
+    BOOST_CHECK ( sr1 == sr3 );
+    BOOST_CHECK ( sr2 == sr3 );
+    BOOST_CHECK ( sr1 == sr4 );    
+    }
+
+//  make sure that substrings work just like strings
+void test_substr ( const std::string &str ) {
+    const size_t sz = str.size ();
+    string_ref ref ( str );
+    
+//  Substrings at the end
+    for ( size_t i = 0; i <= sz; ++ i )
+        interop ( str.substr ( i ), ref.substr ( i ));
+        
+//  Substrings at the beginning
+    for ( size_t i = 0; i <= sz; ++ i )
+        interop ( str.substr ( 0, i ), ref.substr ( 0, i ));
+        
+//  All possible substrings
+    for ( size_t i = 0; i < sz; ++i )
+        for ( size_t j = i; j < sz; ++j )
+            interop ( str.substr ( i, j ), ref.substr ( i, j ));    
+    }
+
+//  make sure that removing prefixes and suffixes work just like strings
+void test_remove ( const std::string &str ) {
+    const size_t sz = str.size ();
+    std::string work;
+    string_ref ref;
+    
+    for ( size_t i = 1; i <= sz; ++i ) {
+      work = str;
+      ref  = str;     
+      while ( ref.size () >= i ) {
+          interop ( work, ref );
+          work.erase ( 0, i );
+          ref.remove_prefix (i);
+          }
+      }
+    
+    for ( size_t i = 1; i < sz; ++ i ) {
+      work = str;
+      ref  = str;     
+      while ( ref.size () >= i ) {
+          interop ( work, ref );
+          work.erase ( work.size () - i, i );
+          ref.remove_suffix (i);
+          }
+      }
+    }
+
+const char *test_strings [] = {
+    "",
+    "1",
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
+    "0123456789",
+    NULL
+    };
+    
+int test_main( int , char* [] ) {
+
+    const char **p = &test_strings[0];
+
+    while ( *p != NULL ) {
+        interop ( *p, *p );
+        test_substr ( *p );
+        test_remove ( *p );
+        null_tests ( *p );
+    
+        p++;
+        }
+
+    return 0;
+    }
--- a/test/string_ref_test2.cpp
+++ b/test/string_ref_test2.cpp
@@ -0,0 +1,256 @@
+/* 
+   Copyright (c) Marshall Clow 2012-2012.
+
+   Distributed under the Boost Software License, Version 1.0. (See accompanying
+   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+    For more information, see http://www.boost.org
+*/
+
+#include <iostream>
+#include <cstring>    // for std::strchr
+
+#include <boost/utility/string_ref.hpp>
+
+#include <boost/test/included/test_exec_monitor.hpp>
+
+typedef boost::string_ref string_ref;
+
+void ends_with ( const char *arg ) {
+    const size_t sz = strlen ( arg );
+    string_ref sr ( arg );
+    string_ref sr2 ( arg );
+    const char *p = arg;
+
+    while ( !*p ) {
+        BOOST_CHECK ( sr.ends_with ( p ));
+        ++p;
+        }
+
+    while ( !sr2.empty ()) {
+        BOOST_CHECK ( sr.ends_with ( sr2 ));
+        sr2.remove_prefix (1);
+        }
+
+    sr2 = arg;
+    while ( !sr2.empty ()) {
+        BOOST_CHECK ( sr.ends_with ( sr2 ));
+        sr2.remove_prefix (1);
+        }
+
+    char ch = sz == 0 ? '\0' : arg [ sz - 1 ];
+    sr2 = arg;
+    if ( sz > 0 )
+      BOOST_CHECK ( sr2.ends_with ( ch ));
+    BOOST_CHECK ( !sr2.ends_with ( ++ch ));
+    BOOST_CHECK ( sr2.ends_with ( string_ref ()));
+    }
+    
+void starts_with ( const char *arg ) {
+    const size_t sz = strlen ( arg );
+    string_ref sr  ( arg );
+    string_ref sr2 ( arg );
+    const char *p = arg + std::strlen ( arg ) - 1;
+    while ( p >= arg ) {
+        std::string foo ( arg, p + 1 );
+        BOOST_CHECK ( sr.starts_with ( foo ));
+        --p;
+        }
+
+    while ( !sr2.empty ()) {
+        BOOST_CHECK ( sr.starts_with ( sr2 ));
+        sr2.remove_suffix (1);
+        }
+
+    char ch = *arg;
+    sr2 = arg;
+  if ( sz > 0 )
+    BOOST_CHECK ( sr2.starts_with ( ch ));
+    BOOST_CHECK ( !sr2.starts_with ( ++ch ));
+    BOOST_CHECK ( sr2.starts_with ( string_ref ()));
+    }
+
+void reverse ( const char *arg ) {
+//  Round trip
+    string_ref sr1 ( arg );
+    std::string string1 ( sr1.rbegin (), sr1.rend ());
+    string_ref sr2 ( string1 );
+    std::string string2 ( sr2.rbegin (), sr2.rend ());
+
+    BOOST_CHECK ( std::equal ( sr2.rbegin (), sr2.rend (), arg ));
+    BOOST_CHECK ( string2 == arg );
+    BOOST_CHECK ( std::equal ( sr1.begin (), sr1.end (), string2.begin ()));
+    }
+
+//	This helper function eliminates signed vs. unsigned warnings
+string_ref::size_type ptr_diff ( const char *res, const char *base ) {
+	BOOST_CHECK ( res >= base );
+	return static_cast<string_ref::size_type> ( res - base );
+	}
+
+void find ( const char *arg ) {
+    string_ref sr1;
+    string_ref sr2;
+    const char *p;
+
+//  Look for each character in the string(searching from the start)
+  p = arg;
+  sr1 = arg;
+  while ( *p ) {
+    string_ref::size_type pos = sr1.find(*p);
+    BOOST_CHECK ( pos != string_ref::npos && ( pos <= ptr_diff ( p, arg )));
+    ++p;
+    }
+  
+//  Look for each character in the string (searching from the end)
+    p = arg;
+    sr1 = arg;
+    while ( *p ) {
+    string_ref::size_type pos = sr1.rfind(*p);
+    BOOST_CHECK ( pos != string_ref::npos && pos < sr1.size () && ( pos >= ptr_diff ( p, arg )));
+    ++p;
+    }
+
+    sr1 = arg;
+    p = arg;
+//  for all possible chars, see if we find them in the right place.
+//  Note that strchr will/might do the _wrong_ thing if we search for NULL
+    for ( int ch = 1; ch < 256; ++ch ) {
+        string_ref::size_type pos = sr1.find(ch);
+        const char *strp = std::strchr ( arg, ch );
+        BOOST_CHECK (( strp == NULL ) == ( pos == string_ref::npos ));
+        if ( strp != NULL )
+            BOOST_CHECK ( ptr_diff ( strp, arg ) == pos );
+    }
+
+    sr1 = arg;
+    p = arg;
+//  for all possible chars, see if we find them in the right place.
+//  Note that strchr will/might do the _wrong_ thing if we search for NULL
+    for ( int ch = 1; ch < 256; ++ch ) {
+        string_ref::size_type pos = sr1.rfind(ch);
+        const char *strp = std::strrchr ( arg, ch );
+        BOOST_CHECK (( strp == NULL ) == ( pos == string_ref::npos ));
+        if ( strp != NULL )
+            BOOST_CHECK ( ptr_diff ( strp, arg ) == pos );
+    }
+
+
+//  Find everything at the start
+    p = arg;
+    sr1 = arg;
+    while ( !sr1.empty ()) {
+        string_ref::size_type pos = sr1.find(*p);
+        BOOST_CHECK ( pos == 0 );
+        sr1.remove_prefix (1);
+        ++p;
+        }
+
+//  Find everything at the end
+    sr1  = arg;
+    p    = arg + strlen ( arg ) - 1;
+    while ( !sr1.empty ()) {
+        string_ref::size_type pos = sr1.rfind(*p);
+        BOOST_CHECK ( pos == sr1.size () - 1 );
+        sr1.remove_suffix (1);
+        --p;
+        }
+        
+//  Find everything at the start
+    sr1  = arg;
+    p    = arg;
+    while ( !sr1.empty ()) {
+        string_ref::size_type pos = sr1.find_first_of(*p);
+        BOOST_CHECK ( pos == 0 );
+        sr1.remove_prefix (1);
+        ++p;
+        }
+
+
+//  Find everything at the end
+    sr1  = arg;
+    p    = arg + strlen ( arg ) - 1;
+    while ( !sr1.empty ()) {
+        string_ref::size_type pos = sr1.find_last_of(*p);
+        BOOST_CHECK ( pos == sr1.size () - 1 );
+        sr1.remove_suffix (1);
+        --p;
+        }
+        
+//  Basic sanity checking for "find_first_of / find_first_not_of"
+    sr1 = arg;
+    sr2 = arg;
+    while ( !sr1.empty() ) {
+        BOOST_CHECK ( sr1.find_first_of ( sr2 )     == 0 );
+        BOOST_CHECK ( sr1.find_first_not_of ( sr2 ) == string_ref::npos );
+        sr1.remove_prefix ( 1 );
+        }
+
+    p = arg;
+    sr1 = arg;
+    while ( *p ) {
+        string_ref::size_type pos1 = sr1.find_first_of(*p);
+        string_ref::size_type pos2 = sr1.find_first_not_of(*p);
+        BOOST_CHECK ( pos1 != string_ref::npos && pos1 < sr1.size () && pos1 <= ptr_diff ( p, arg ));
+        if ( pos2 != string_ref::npos ) {
+            for ( size_t i = 0 ; i < pos2; ++i )
+                BOOST_CHECK ( sr1[i] == *p );
+            BOOST_CHECK ( sr1 [ pos2 ] != *p );
+            }
+
+        BOOST_CHECK ( pos2 != pos1 );
+        ++p;
+        }
+        
+//  Basic sanity checking for "find_last_of / find_last_not_of"
+    sr1 = arg;
+    sr2 = arg;
+    while ( !sr1.empty() ) {
+        BOOST_CHECK ( sr1.find_last_of ( sr2 )     == ( sr1.size () - 1 ));
+        BOOST_CHECK ( sr1.find_last_not_of ( sr2 ) == string_ref::npos );
+        sr1.remove_suffix ( 1 );
+        }
+
+    p = arg;
+    sr1 = arg;
+    while ( *p ) {
+        string_ref::size_type pos1 = sr1.find_last_of(*p);
+        string_ref::size_type pos2 = sr1.find_last_not_of(*p);
+        BOOST_CHECK ( pos1 != string_ref::npos && pos1 < sr1.size () && pos1 >= ptr_diff ( p, arg ));
+        BOOST_CHECK ( pos2 == string_ref::npos || pos1 < sr1.size ());
+        if ( pos2 != string_ref::npos ) {
+            for ( size_t i = sr1.size () -1 ; i > pos2; --i )
+                BOOST_CHECK ( sr1[i] == *p );
+            BOOST_CHECK ( sr1 [ pos2 ] != *p );
+            }
+         
+        BOOST_CHECK ( pos2 != pos1 );
+        ++p;
+        }
+
+    }
+
+const char *test_strings [] = {
+    "",
+    "0",
+    "abc",
+    "AAA",  // all the same
+    "adsfadadiaef;alkdg;aljt;j agl;sjrl;tjs;lga;lretj;srg[w349u5209dsfadfasdfasdfadsf",
+    "abc\0asdfadsfasf",
+    NULL
+    };
+    
+int test_main( int , char* [] ) {
+    const char **p = &test_strings[0];
+    
+    while ( *p != NULL ) {
+        starts_with ( *p );
+        ends_with ( *p );
+        reverse ( *p );
+        find ( *p );
+
+        p++;
+        }
+
+    return 0;
+    }
--- a/utility.htm
+++ b/utility.htm
@@ -143,7 +143,7 @@ void f() {
                <h2><a name="result_of">Class template
                result_of</a></h2> <p>The class template
                <code>result_of</code> helps determine the type of a
-                call expression. Given an lvalue <code>f</code> of
+                call expression. For example, given an lvalue <code>f</code> of
                type <code>F</code> and lvalues <code>t1</code>,
                <code>t2</code>, ..., <code>t<em>N</em></code> of
                types <code>T1</code>, <code>T2</code>, ...,
@@ -155,22 +155,24 @@ void f() {
                the type <code>F</code> to be a function pointer,
                function reference, member function pointer, or class
                type. By default, <em>N</em> may be any value between 0 and
-                10. To change the upper limit, define the macro
+                16. To change the upper limit, define the macro
                <code>BOOST_RESULT_OF_NUM_ARGS</code> to the maximum
                value for <em>N</em>. Class template <code>result_of</code>
                resides in the header <code>&lt;<a
                href="../../boost/utility/result_of.hpp">boost/utility/result_of.hpp</a>&gt;</code>.</p>

-                <p>If your compiler supports <code>decltype</code>,
-                then you can enable automatic result type deduction by
-                defining the macro <code>BOOST_RESULT_OF_USE_DECLTYPE</code>,
-                as in the following example.</p>
+                <p>If your compiler's support for <code>decltype</code> is
+                adequate, <code>result_of</code> automatically uses it to
+                deduce the type of the call expression, in which case
+                <code>result_of&lt;F(T1, T2, ...,
+                T<em>N</em>)&gt;::type</code> names the type
+                <code>decltype(boost::declval&lt;F&gt;()(boost::declval&lt;T1&gt;(),
+                boost::declval&lt;T2&gt;(), ...,
+                boost::declval&lt;T<em>N</em>&gt;()))</code>, as in the
+                following example.</p>

                <blockquote>
-                <pre>#define BOOST_RESULT_OF_USE_DECLTYPE
-#include &lt;boost/utility/result_of.hpp&gt;
-
-struct functor {
+                <pre>struct functor {
    template&lt;class T&gt;
    T operator()(T x)
    {
@@ -180,21 +182,29 @@ struct functor {

 typedef boost::result_of&lt;
    functor(int)
-&gt;::type type;</pre>
+&gt;::type type; // type is int</pre>
                </blockquote>

-                <p>If <code>decltype</code> is not enabled,
+                <p>You can test whether <code>result_of</code> is using
+                <code>decltype</code> by checking if the macro
+                <code>BOOST_RESULT_OF_USE_DECLTYPE</code> is defined after
+                including <code>result_of.hpp</code>. You can also force
+                <code>result_of</code> to use <code>decltype</code> by
+                defining <code>BOOST_RESULT_OF_USE_DECLTYPE</code> prior
+                to including <code>result_of.hpp</code>.</p>
+
+                <p>If <code>decltype</code> is not used,
                then automatic result type deduction of function
                objects is not possible. Instead, <code>result_of</code>
                uses the following protocol to allow the programmer to
                specify a type. When <code>F</code> is a class type with a
                member type <code>result_type</code>,
                <code>result_of&lt;F(T1, T2, ...,
-                T<em>N</em>)&gt;</code> is
+                T<em>N</em>)&gt;::type</code> is
                <code>F::result_type</code>. When <code>F</code> does
                not contain <code>result_type</code>,
                <code>result_of&lt;F(T1, T2, ...,
-                T<em>N</em>)&gt;</code> is <code>F::result&lt;F(T1,
+                T<em>N</em>)&gt;::type</code> is <code>F::result&lt;F(T1,
                T2, ..., T<em>N</em>)&gt;::type</code> when
                <code><em>N</em> &gt; 0</code> or <code>void</code>
                when <code><em>N</em> = 0</code>. Note that it is the
@@ -221,22 +231,29 @@ typedef boost::result_of&lt;

 typedef boost::result_of&lt;
    functor(int)
-&gt;::type type;</pre>
+&gt;::type type; // type is int</pre>
                </blockquote>

-                <p>In a future
-                release, <code>BOOST_RESULT_OF_USE_DECLTYPE</code>
-                may be enabled by default on compilers that
-                support <code>decltype</code>, so if you use the above
-                protocol please take care to ensure that
-                the <code>result_type</code>
-                and <code>result&lt;&gt;</code> members accurately
-                represent the result type. If you wish to continue to
+                <p>Since <code>decltype</code> is a new language
+                feature recently standardized in C++11,
+                if you are writing a function object
+                to be used with <code>result_of</code>, for
+                maximum portability, you might consider following
+                the above protocol even if your compiler has
+                proper <code>decltype</code> support. If you wish to continue to
                use the protocol on compilers that
-                support <code>decltype</code>,
-                use <code>boost::tr1_result_of</code>, which is also
-                defined
-                in <code>&lt;<a href="../../boost/utility/result_of.hpp">boost/utility/result_of.hpp</a>&gt;</code>.</p>
+                support <code>decltype</code>, there are two options:
+                You can use <code>boost::tr1_result_of</code>, which is also
+                defined in <code>&lt;<a href="../../boost/utility/result_of.hpp">boost/utility/result_of.hpp</a>&gt;</code>.
+                Alternatively, you can define the macro
+                <code>BOOST_RESULT_OF_USE_TR1</code>, which causes
+                <code>result_of</code> to use the protocol described
+                above instead of <code>decltype</code>. If you choose to
+                follow the protocol, take care to ensure that the
+                <code>result_type</code> and
+                <code>result&lt;&gt;</code> members accurately
+                represent the return type of
+                <code>operator()</code> given a call expression.</p>

                <a name="BOOST_NO_RESULT_OF"></a>
                <p>This implementation of <code>result_of</code>
@@ -253,7 +270,322 @@ typedef boost::result_of&lt;
                <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1836.pdf">N1836</a>,
                or, for motivation and design rationale,
                the <code>result_of</code> <a href="http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2003/n1454.html">proposal</a>.</p>
-                Contributed by Doug Gregor.</p>
+
+                <a name="result_of_guidelines">
+                <h3>Usage guidelines for boost::result_of</h3>
+                </a>
+
+                <p>The following are general suggestions about when
+                and how to use <code>boost::result_of</code>.</p>
+
+                <ol>
+                <li> If you are targeting C++11 and are not concerned
+                about portability to non-compliant compilers or
+                previous versions of the standard, then use
+                <code>std::result_of</code>. If <code>std::result_of</code>
+                meets your needs, then there's no reason to stop using
+                it.</li>
+
+                <li> If you are targeting C++11 but may port your code
+                to legacy compilers at some time in the future, then
+                use <code>boost::result_of</code> with
+                <code>decltype</code>. When <code>decltype</code> is
+                used <code>boost::result_of</code>
+                and <code>std::result_of</code> are usually
+                interchangeable. See the documentation on
+                known <a href="#result_of_cxx11_diff">differences</a>
+                between boost::result_of and C++11 result_of.</li>
+
+                <li> If compiler portability is required,
+                use <code>boost::result_of</code> with the TR1 protocol.</li>
+                </ol>
+
+                <p>Regardless of how you
+                configure <code>boost::result_of</code>, it is
+                important to bear in mind that the return type of a
+                function may change depending on its arguments, and
+                additionally, the return type of a member function may
+                change depending on the cv-qualification of the
+                object. <code>boost::result_of</code> must be passed
+                the appropriately cv-qualified types in order to
+                deduce the corresponding return type. For example:
+
+                <blockquote>
+                <pre>struct functor {
+    int& operator()(int);
+    int const& operator()(int) const;
+
+    float& operator()(float&);
+    float const& operator()(float const&);
+};
+
+typedef boost::result_of&lt;
+    functor(int)
+&gt;::type type1; // type1 is int &
+
+typedef boost::result_of&lt;
+    const functor(int)
+&gt;::type type2; // type2 is int const &
+
+typedef boost::result_of&lt;
+    functor(float&)
+&gt;::type type3; // type3 is float &
+
+typedef boost::result_of&lt;
+    functor(float const&)
+&gt;::type type4; // type4 is float const &</pre>
+                </blockquote>
+
+                <a name="result_of_tr1_protocol_guidelines">
+                <h3>Usage guidelines for the TR1 result_of protocol</h3>
+                </a>
+
+                <p>On compliant C++11
+                compilers, <code>boost::result_of</code> can
+                use <code>decltype</code> to deduce the type of any
+                call expression, including calls to function
+                objects. However, on pre-C++11 compilers or on
+                compilers without adequate decltype support,
+                additional scaffolding is needed from function
+                objects as described above. The following are
+                suggestions about how to use the TR1 protocol.</p>
+
+                <ul>
+                    <li>When the return type does not depend on the
+                    argument types or the cv-qualification of the
+                    function object, simply
+                    define <code>result_type</code>. There is no need
+                    to use the <code>result</code> template unless the
+                    return type varies.</li>
+
+                    <li>Use the protocol specified type when defining
+                    function prototypes. This can help ensure the
+                    actual return type does not get out of sync with
+                    the protocol specification. For example:
+
+                   <blockquote>
+                   <pre>struct functor {
+    typedef int result_type;
+    result_type operator()(int);
+};</pre>
+                   </blockquote> </li>
+
+                   <li>Always specify the <code>result</code>
+                   specialization near the corresponding
+                   <code>operator()</code> overload. This can make it
+                   easier to keep the specializations in sync with the
+                   overloads. For example:
+
+                   <blockquote>
+                   <pre>struct functor {
+    template&lt;class&gt; struct result;
+
+    template&lt;class F&gt;
+    struct result&lt;F(int)&gt; {
+        typedef int& type;
+    };
+    result&lt;functor(int)&gt;::type operator()(int);
+
+    template&lt;class F&gt;
+    struct result&lt;const F(int)&gt; {
+        typedef int const& type;
+    };
+    result&lt;const functor(int)&gt;::type operator()(int) const;
+};</pre>
+                   </blockquote> </li>
+
+                   <li>Use type transformations to simplify
+                   the <code>result</code> template specialization. For
+                   example, the following uses
+                   <a href="../type_traits/doc/html/index.html">Boost.TypeTraits</a>
+                   to specialize the <code>result</code> template for
+                   a single <code>operator()</code> that can be called on
+                   both a const and non-const function object with
+                   either an lvalue or rvalue argument.
+
+                   <blockquote>
+                   <pre>struct functor {
+    template&lt;class&gt; struct result;
+
+    template&lt;class F, class T&gt;
+    struct result&lt;F(T)&gt; 
+        : boost::remove_cv&lt;
+              typename boost::remove_reference&lt;T&gt;::type
+          &gt;
+    {};
+
+    template&lt;class T&gt;
+    T operator()(T const&amp; x) const;
+};</pre>
+                   </blockquote></li>
+                </ul>
+
+                <a name="result_of_tr1_diff">
+                <h3>Known differences between boost::result_of and TR1 result_of</h3>
+                </a>
+
+                When using <code>decltype</code>, <code>boost::result_of</code>
+                ignores the TR1 protocol and instead deduces the
+                return type of function objects directly
+                via <code>decltype</code>. In most situations, users
+                will not notice a difference, so long as they use the
+                protocol correctly. The following are situations in
+                which the type deduced
+                by <code>boost::result_of</code> is known to differ depending on
+                whether <code>decltype</code> or the TR1 protocol is
+                used.
+
+                <ul>
+                <li> TR1 protocol misusage
+
+                     <p>When using the TR1
+                     protocol, <code>boost::result_of</code> cannot
+                     detect whether the actual type of a call to a
+                     function object is the same as the type specified
+                     by the protocol, which allows for the possibility
+                     of inadvertent mismatches between the specified
+                     type and the actual type. When
+                     using <code>decltype</code>, these subtle bugs
+                     may result in compilation errors. For example:</p>
+
+                     <blockquote>
+                     <pre>struct functor {
+   typedef short result_type;
+   int operator()(short);
+};
+
+#ifdef BOOST_RESULT_OF_USE_DECLTYPE
+
+BOOST_STATIC_ASSERT((
+   boost::is_same&lt;boost::result_of&lt;functor(short)&gt;::type, int&gt;::value
+)); 
+
+#else
+
+BOOST_STATIC_ASSERT((
+   boost::is_same&lt;boost::result_of&lt;functor(short)&gt;::type, short&gt;::value
+));
+
+#endif</pre>
+                   </blockquote>
+
+                  <p>Note that the user can
+                  force <code>boost::result_of</code> to use the TR1
+                  protocol even on platforms that
+                  support <code>decltype</code> by
+                  defining <code>BOOST_RESULT_OF_USE_TR1</code>.</p></li>
+
+                  <li> Nullary function objects
+
+                       <p>When using the TR1 protocol, <code>boost::result_of</code>
+                       cannot always deduce the type of calls to
+                       nullary function objects, in which case the
+                       type defaults to void. When using <code>decltype</code>,
+                       <code>boost::result_of</code> always gives the actual type of the
+                       call expression. For example:</p>
+
+                       <blockquote>
+                       <pre>struct functor {
+   template&lt;class&gt; struct result {
+       typedef int type;
+   };
+   int operator()();
+};
+
+#ifdef BOOST_RESULT_OF_USE_DECLTYPE
+
+BOOST_STATIC_ASSERT((
+   boost::is_same&lt;boost::result_of&lt;functor()&gt;::type, int&gt;::value
+));
+
+#else
+
+BOOST_STATIC_ASSERT((
+   boost::is_same&lt;boost::result_of&lt;functor()&gt;::type, void&gt;::value
+));
+
+#endif</pre>
+                       </blockquote>
+
+                       <p>Note that there are some workarounds for the
+                       nullary function problem. So long as the return
+                       type does not vary,
+                       <code>result_type</code> can always be used to
+                       specify the return type regardless of arity. If the
+                       return type does vary, then the user can
+                       specialize <code>boost::result_of</code> itself for
+                       nullary calls.</p></li>
+
+                  <li> Non-class prvalues and cv-qualification
+
+                       <p>When using the TR1
+                       protocol, <code>boost::result_of</code> will
+                       report the cv-qualified type specified
+                       by <code>result_type</code> or
+                       the <code>result</code> template regardless of
+                       the actual cv-qualification of the call
+                       expression. When using
+                       <code>decltype</code>, <code>boost::result_of</code>
+                       will report the actual type of the call expression,
+                       which is not cv-qualified when the expression is a
+                       non-class prvalue. For example:</p>
+
+                       <blockquote>
+                       <pre>struct functor {
+   template&lt;class&gt; struct result;
+   template&lt;class F, class T&gt; struct result&lt;F(const T)&gt; {
+       typedef const T type;
+   };
+
+   const short operator()(const short);
+   int const & operator()(int const &);
+};
+
+// Non-prvalue call expressions work the same with or without decltype.
+
+BOOST_STATIC_ASSERT((
+   boost::is_same&lt;
+       boost::result_of&lt;functor(int const &)&gt;::type,
+       int const &
+::value
+));
+
+// Non-class prvalue call expressions are not actually cv-qualified,
+// but only the decltype-based result_of reports this accurately.
+
+#ifdef BOOST_RESULT_OF_USE_DECLTYPE
+
+BOOST_STATIC_ASSERT((
+   boost::is_same&lt;
+       boost::result_of&lt;functor(const short)&gt;::type,
+       short
+::value
+));
+
+#else
+
+BOOST_STATIC_ASSERT((
+   boost::is_same&lt;
+       boost::result_of&lt;functor(const short)&gt;::type,
+       const short
+::value
+));
+
+#endif</pre>
+                       </blockquote></li>
+                </ul>
+
+                <a name="result_of_cxx11_diff">
+                <h3>Known differences between boost::result_of and C++11 result_of</h3>
+                </a>
+
+                <p>When using <code>decltype</code>, <code>boost::result_of</code>
+                implements most of the C++11 result_of
+                specification. One known exception is that
+                <code>boost::result_of</code> does not implement the
+                requirements regarding pointers to member data.</p>
+
+                <p>Created by Doug Gregor. Contributions from Daniel Walker, Eric Niebler, Michel Morin and others</p>

 		<h2>Class templates for the Base-from-Member Idiom</h2>
 		<p>See <a href="base_from_member.html">separate documentation</a>.</p>
Author	SHA1	Message	Date
Marshall Clow	7017915fa0	Release 1.53.0 [SVN r82734]	2013-02-04 18:11:49 +00:00
Marshall Clow	1730c1319b	Merge string_ref doc changes to release [SVN r82490]	2013-01-14 16:34:16 +00:00
Marshall Clow	856b01240a	Merge string_ref to release [SVN r82047]	2012-12-17 14:36:31 +00:00
Marshall Clow	611395441e	Merge deprecated macro change for Boost.Utility to release; no functionality change [SVN r81855]	2012-12-11 16:41:54 +00:00
Eric Niebler	b35ef27b35	add missing close tag [SVN r80835]	2012-10-03 23:09:58 +00:00
Eric Niebler	124f4ea879	result_of: merge [80732] from trunk [SVN r80746]	2012-09-28 22:21:32 +00:00
Eric Niebler	0f43c44e97	result_of: merge [80636],[80654],[80655],[80656],[80712] from trunk [SVN r80713]	2012-09-26 18:52:08 +00:00
Eric Niebler	7d8353f46a	result_of: merge [80445], [80452], [80535], [80550], [80605], [80608] from trunk [SVN r80621]	2012-09-21 18:49:46 +00:00
Daniel Walker	1920623a4f	merged [80550], allowing users to force result_of to use decltype [SVN r80551]	2012-09-17 00:16:36 +00:00
John Maddock	c0cca9e8cc	Merge changes from Trunk. Fixes #5790. [SVN r80433]	2012-09-07 08:49:11 +00:00
Eric Niebler	d63444f22e	merge [77702] to release, fixes #6755 [SVN r80359]	2012-09-02 03:42:37 +00:00
Eric Niebler	1f23425baa	result_of limit bumped to 16, merge [71769] from trunk [SVN r80358]	2012-09-02 03:29:41 +00:00
Eric Niebler	a89b0101fc	boost::result_of uses decltype on compilers that implement N3276, merges [77905], [78195], [80352] from trunk [SVN r80355]	2012-09-01 23:12:32 +00:00