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diff --git a/libs/local_function/doc/html/index.html b/libs/local_function/doc/html/index.html new file mode 100644 index 000000000..c33c28fd5 --- /dev/null +++ b/libs/local_function/doc/html/index.html @@ -0,0 +1,235 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>Chapter 1. Boost.LocalFunction 1.0.0</title> +<link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> +<link rel="home" href="index.html" title="Chapter 1. Boost.LocalFunction 1.0.0"> +<link rel="next" href="boost_localfunction/getting_started.html" title="Getting Started"> +</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 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class="legalnotice"> +<a name="boost_localfunction.legal"></a><p> + Distributed under the Boost Software License, Version 1.0 (see accompanying + file LICENSE_1_0.txt or a 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></div> +<div class="toc"> +<p><b>Table of Contents</b></p> +<dl> +<dt><span class="section"><a href="index.html#boost_localfunction.introduction">Introduction</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/getting_started.html">Getting Started</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="boost_localfunction/getting_started.html#boost_localfunction.getting_started.this_documentation">This + Documentation</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/getting_started.html#boost_localfunction.getting_started.compilers_and_platforms">Compilers + and Platforms</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/getting_started.html#boost_localfunction.getting_started.installation">Installation</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="boost_localfunction/tutorial.html">Tutorial</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="boost_localfunction/tutorial.html#boost_localfunction.tutorial.local_functions">Local Functions</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/tutorial.html#boost_localfunction.tutorial.Binding">Binding Variables</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/tutorial.html#boost_localfunction.tutorial.binding_the_object__this_">Binding + the Object <code class="computeroutput"><span class="keyword">this</span></code></a></span></dt> +<dt><span class="section"><a href="boost_localfunction/tutorial.html#boost_localfunction.tutorial.templates">Templates</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html">Advanced Topics</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.default_parameters">Default + Parameters</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.commas_and_symbols_in_macros">Commas + and Symbols in Macros</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.assignments_and_returns">Assignments + and Returns</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.nesting">Nesting</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.accessing_types__concepts__etc_">Accessing + Types (concepts, etc)</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.specifying_types__no_boost_typeof_">Specifying + Types (no Boost.Typeof)</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.inlining">Inlining</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.recursion">Recursion</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.overloading">Overloading</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.exception_specifications">Exception + Specifications</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.storage_classifiers">Storage + Classifiers</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.same_line_expansions">Same + Line Expansions</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/advanced_topics.html#boost_localfunction.advanced_topics.limitations__operators__etc_">Limitations + (operators, etc)</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="boost_localfunction/examples.html">Examples</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="boost_localfunction/examples.html#boost_localfunction.examples.gcc_lambdas__without_c__11_">GCC + Lambdas (without C++11)</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/examples.html#boost_localfunction.examples.constant_blocks">Constant + Blocks</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/examples.html#boost_localfunction.examples.scope_exits">Scope Exits</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/examples.html#boost_localfunction.examples.boost_phoenix_functions">Boost.Phoenix + Functions</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/examples.html#boost_localfunction.examples.closures">Closures</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/examples.html#boost_localfunction.examples.gcc_nested_functions">GCC + Nested Functions</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/examples.html#boost_localfunction.examples.n_papers">N-Papers</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="boost_localfunction/alternatives.html">Annex: Alternatives</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/no_variadic_macros.html">Annex: No Variadic + Macros</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/implementation.html">Annex: Implementation</a></span></dt> +<dt><span class="section"><a href="reference.html">Reference</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="reference.html#header.boost.local_function_hpp">Header <boost/local_function.hpp></a></span></dt> +<dt><span class="section"><a href="reference.html#header.boost.local_function.config_hpp">Header <boost/local_function/config.hpp></a></span></dt> +</dl></dd> +<dt><span class="section"><a href="boost_localfunction/release_notes.html">Release Notes</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/bibliography.html">Bibliography</a></span></dt> +<dt><span class="section"><a href="boost_localfunction/acknowledgments.html">Acknowledgments</a></span></dt> +</dl> +</div> +<p> + This library allows to program functions locally, within other functions, and + directly within the scope where they are needed. + </p> +<div class="section boost_localfunction_introduction"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="boost_localfunction.introduction"></a><a class="link" href="index.html#boost_localfunction.introduction" title="Introduction">Introduction</a> +</h2></div></div></div> +<p> + <span class="emphasis"><em>Local functions</em></span> (a.k.a., <a href="http://en.wikipedia.org/wiki/Nested_function" target="_top"><span class="emphasis"><em>nested + functions</em></span></a>) are a form of <span class="emphasis"><em>information hiding</em></span> + and they are useful for dividing procedural tasks into subtasks which are only + meaningful locally, avoiding cluttering other parts of the program with functions, + variables, etc unrelated to those parts. Therefore, local functions complement + other structuring possibilities such as namespaces and classes. Local functions + are a feature of many programming languages, notably <a href="http://en.wikipedia.org/wiki/Nested_function#An_example" target="_top">Pascal</a> + and <a href="http://en.wikipedia.org/wiki/Nesting_(computing)#In_programming" target="_top">Ada</a>, + yet lacking from <a href="http://www.open-std.org/JTC1/SC22/WG21/docs/standards" target="_top">C++03</a> + (see also <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2511.html" target="_top">[N2511]</a>). + </p> +<p> + Using <a href="http://en.wikipedia.org/wiki/C%2B%2B0x#Lambda_functions_and_expressions" target="_top">C++11 + lambda functions</a>, it is possible to implement local functions by naming + lambda functions assigning them to local variables. For example (see also + <a href="../../example/add_cxx11_lambda.cpp" target="_top"><code class="literal">add_cxx11_lambda.cpp</code></a>): + </p> +<p> +</p> +<pre class="programlisting"><span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span> <span class="special">{</span> <span class="comment">// Some local scope.</span> + <span class="keyword">int</span> <span class="identifier">sum</span> <span class="special">=</span> <span class="number">0</span><span class="special">,</span> <span class="identifier">factor</span> <span class="special">=</span> <span class="number">10</span><span class="special">;</span> <span class="comment">// Variables in scope to bind.</span> + + <span class="keyword">auto</span> <span class="identifier">add</span> <span class="special">=</span> <span class="special">[</span><span class="identifier">factor</span><span class="special">,</span> <span class="special">&</span><span class="identifier">sum</span><span class="special">](</span><span class="keyword">int</span> <span class="identifier">num</span><span class="special">)</span> <span class="special">{</span> <span class="comment">// C++11 only.</span> + <span class="identifier">sum</span> <span class="special">+=</span> <span class="identifier">factor</span> <span class="special">*</span> <span class="identifier">num</span><span class="special">;</span> + <span class="special">};</span> + + <span class="identifier">add</span><span class="special">(</span><span class="number">1</span><span class="special">);</span> <span class="comment">// Call the lambda.</span> + <span class="keyword">int</span> <span class="identifier">nums</span><span class="special">[]</span> <span class="special">=</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="identifier">std</span><span class="special">::</span><span class="identifier">for_each</span><span class="special">(</span><span class="identifier">nums</span><span class="special">,</span> <span class="identifier">nums</span> <span class="special">+</span> <span class="number">2</span><span class="special">,</span> <span class="identifier">add</span><span class="special">);</span> <span class="comment">// Pass it to an algorithm.</span> + + <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">sum</span> <span class="special">==</span> <span class="number">60</span><span class="special">);</span> <span class="comment">// Assert final summation value.</span> + <span class="keyword">return</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">report_errors</span><span class="special">();</span> +<span class="special">}</span> +</pre> +<p> + </p> +<p> + This library allows to program local functions portably between <a href="http://www.open-std.org/JTC1/SC22/WG21/docs/standards" target="_top">C++03</a> + and <a href="http://www.open-std.org/JTC1/SC22/WG21/" target="_top">C++11</a> (and + with performances comparable to lambda functions on <a href="http://www.open-std.org/JTC1/SC22/WG21/" target="_top">C++11</a> + compilers). For example (see also <a href="../../test/add.cpp" target="_top"><code class="literal">add.cpp</code></a>): + </p> +<p> +</p> +<pre class="programlisting"><span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span> <span class="special">{</span> <span class="comment">// Some local scope.</span> + <span class="keyword">int</span> <span class="identifier">sum</span> <span class="special">=</span> <span class="number">0</span><span class="special">,</span> <span class="identifier">factor</span> <span class="special">=</span> <span class="number">10</span><span class="special">;</span> <span class="comment">// Variables in scope to bind.</span> + + <span class="keyword">void</span> <span class="identifier">BOOST_LOCAL_FUNCTION</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">bind</span> <span class="identifier">factor</span><span class="special">,</span> <span class="identifier">bind</span><span class="special">&</span> <span class="identifier">sum</span><span class="special">,</span> <span class="keyword">int</span> <span class="identifier">num</span><span class="special">)</span> <span class="special">{</span> + <span class="identifier">sum</span> <span class="special">+=</span> <span class="identifier">factor</span> <span class="special">*</span> <span class="identifier">num</span><span class="special">;</span> + <span class="special">}</span> <span class="identifier">BOOST_LOCAL_FUNCTION_NAME</span><span class="special">(</span><span class="identifier">add</span><span class="special">)</span> + + <span class="identifier">add</span><span class="special">(</span><span class="number">1</span><span class="special">);</span> <span class="comment">// Call the local function.</span> + <span class="keyword">int</span> <span class="identifier">nums</span><span class="special">[]</span> <span class="special">=</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="identifier">std</span><span class="special">::</span><span class="identifier">for_each</span><span class="special">(</span><span class="identifier">nums</span><span class="special">,</span> <span class="identifier">nums</span> <span class="special">+</span> <span class="number">2</span><span class="special">,</span> <span class="identifier">add</span><span class="special">);</span> <span class="comment">// Pass it to an algorithm.</span> + + <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">sum</span> <span class="special">==</span> <span class="number">60</span><span class="special">);</span> <span class="comment">// Assert final summation value.</span> + <span class="keyword">return</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">report_errors</span><span class="special">();</span> +<span class="special">}</span> +</pre> +<p> + </p> +<p> + This library supports the following features for local functions: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + Local functions can capture, or better <a href="http://en.wikipedia.org/wiki/Name_binding" target="_top"><span class="emphasis"><em>bind</em></span></a>, + any of the variables from the enclosing scope (a function together with + its captured variables is also called a <a href="http://en.wikipedia.org/wiki/Closure_(computer_science)" target="_top"><span class="emphasis"><em>closure</em></span></a>). + </li> +<li class="listitem"> + The local function body is programmed using the usual C++ statement syntax + (as a consequence, compiler errors and debugging retain their usual meaning + and format). + </li> +<li class="listitem"> + Local functions can be passed as template parameters so they can be conveniently + used with STL algorithms and other templates. <sup>[<a name="boost_localfunction.introduction.f0" href="#ftn.boost_localfunction.introduction.f0" class="footnote">1</a>]</sup> + </li> +<li class="listitem"> + However, local functions must be specified within a declarative context + (e.g., at a point in the code where local variables can be declared) thus + they cannot be specified within expressions. <sup>[<a name="boost_localfunction.introduction.f1" href="#ftn.boost_localfunction.introduction.f1" class="footnote">2</a>]</sup> + </li> +</ul></div> +<p> + See the <a class="link" href="boost_localfunction/alternatives.html" title="Annex: Alternatives">Alternatives</a> + section for a comparison between this library, <a href="http://en.wikipedia.org/wiki/C%2B%2B0x#Lambda_functions_and_expressions" target="_top">C++11 + lambda functions</a>, <a href="http://www.boost.org/libs/phoenix" target="_top">Boost.Phoenix</a>, + and other C++ techniques that implement features related to local functions. + </p> +</div> +<div class="footnotes"> +<br><hr width="100" align="left"> +<div class="footnote"><p><sup>[<a id="ftn.boost_localfunction.introduction.f0" href="#boost_localfunction.introduction.f0" class="para">1</a>] </sup> + This is a strength with respect to <a href="http://www.open-std.org/JTC1/SC22/WG21/docs/standards" target="_top">C++03</a> + functors implemented using local classes which cannot be passed as template + parameters (see <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm" target="_top">[N2657]</a> + and the <a class="link" href="boost_localfunction/alternatives.html" title="Annex: Alternatives">Alternatives</a> + section). + </p></div> +<div class="footnote"><p><sup>[<a id="ftn.boost_localfunction.introduction.f1" href="#boost_localfunction.introduction.f1" class="para">2</a>] </sup> + This is a weakness with respect to <a href="http://en.wikipedia.org/wiki/C%2B%2B0x#Lambda_functions_and_expressions" target="_top">C++11 + lambda functions</a> which can instead be specified also within expressions + (see the <a class="link" href="boost_localfunction/alternatives.html" title="Annex: Alternatives">Alternatives</a> + section). + </p></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: April 28, 2012 at 02:07:02 GMT</small></p></td> +<td align="right"><div class="copyright-footer"></div></td> +</tr></table> +<hr> +<div class="spirit-nav"><a accesskey="n" href="boost_localfunction/getting_started.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a></div> +</body> +</html> |