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Reorganized docs. Minor code fix wrt opt refs
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Andrzej Krzemienski
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<div class="toc">
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<p><b>Table of Contents</b></p>
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<dl class="toc">
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<dt><span class="section"><a href="index.html#optional.introduction">Introduction</a></span></dt>
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<dt><span class="section"><a href="boost_optional/quick_start.html">Quick Start</a></span></dt>
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<dt><span class="section"><a href="optional/tutorial.html">Tutorial</a></span></dt>
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<dd><dl>
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<dt><span class="section"><a href="index.html#optional.introduction.problem">Problem</a></span></dt>
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<dt><span class="section"><a href="index.html#optional.introduction.solution">Solution</a></span></dt>
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<dt><span class="section"><a href="boost_optional/tutorial/motivation.html">Motivation</a></span></dt>
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<dt><span class="section"><a href="boost_optional/tutorial/design_overview.html">Design Overview</a></span></dt>
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<dt><span class="section"><a href="boost_optional/tutorial/optional_references.html">Optional
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references</a></span></dt>
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<dt><span class="section"><a href="boost_optional/tutorial/rebinding_semantics_for_assignment_of_optional_references.html">Rebinding
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semantics for assignment of optional references</a></span></dt>
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<dt><span class="section"><a href="boost_optional/tutorial/in_place_factories.html">In-Place
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Factories</a></span></dt>
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<dt><span class="section"><a href="boost_optional/tutorial/a_note_about_optional_bool_.html">A
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note about optional<bool></a></span></dt>
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<dt><span class="section"><a href="boost_optional/tutorial/exception_safety_guarantees.html">Exception
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Safety Guarantees</a></span></dt>
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<dt><span class="section"><a href="boost_optional/tutorial/type_requirements.html">Type requirements</a></span></dt>
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</dl></dd>
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<dt><span class="section"><a href="boost_optional/tutorial.html">Tutorial</a></span></dt>
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<dt><span class="section"><a href="optional/reference.html">Reference</a></span></dt>
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<dd><dl>
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<dt><span class="section"><a href="boost_optional/tutorial.html#boost_optional.tutorial.optional_return_values">Optional
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return values</a></span></dt>
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<dt><span class="section"><a href="boost_optional/tutorial.html#boost_optional.tutorial.optional_data_members">Optional
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data members</a></span></dt>
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<dt><span class="section"><a href="boost_optional/tutorial.html#boost_optional.tutorial.bypassing_unnecessary_default_construction">Bypassing
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unnecessary default construction</a></span></dt>
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<dt><span class="section"><a href="boost_optional/reference/synopsis.html">Synopsis</a></span></dt>
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<dt><span class="section"><a href="boost_optional/reference/detailed_semantics.html">Detailed
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Semantics</a></span></dt>
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</dl></dd>
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<dt><span class="section"><a href="boost_optional/discussion.html">Discussion</a></span></dt>
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<dt><span class="section"><a href="boost_optional/development.html">Development</a></span></dt>
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<dd><dl>
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<dt><span class="section"><a href="boost_optional/development.html#boost_optional.development.the_models">The models</a></span></dt>
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<dt><span class="section"><a href="boost_optional/development.html#boost_optional.development.the_semantics">The semantics</a></span></dt>
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<dt><span class="section"><a href="boost_optional/development.html#boost_optional.development.the_interface">The Interface</a></span></dt>
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</dl></dd>
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<dt><span class="section"><a href="boost_optional/synopsis.html">Synopsis</a></span></dt>
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<dt><span class="section"><a href="boost_optional/detailed_semantics.html">Detailed Semantics</a></span></dt>
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<dt><span class="section"><a href="boost_optional/examples.html">Examples</a></span></dt>
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<dd><dl>
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<dt><span class="section"><a href="boost_optional/examples.html#boost_optional.examples.optional_return_values">Optional
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return values</a></span></dt>
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<dt><span class="section"><a href="boost_optional/examples.html#boost_optional.examples.optional_local_variables">Optional
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local variables</a></span></dt>
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<dt><span class="section"><a href="boost_optional/examples.html#boost_optional.examples.optional_data_members">Optional
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data members</a></span></dt>
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<dt><span class="section"><a href="boost_optional/examples.html#boost_optional.examples.bypassing_expensive_unnecessary_default_construction">Bypassing
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expensive unnecessary default construction</a></span></dt>
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</dl></dd>
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<dt><span class="section"><a href="boost_optional/optional_references.html">Optional references</a></span></dt>
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<dt><span class="section"><a href="boost_optional/rebinding_semantics_for_assignment_of_optional_references.html">Rebinding
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semantics for assignment of optional references</a></span></dt>
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<dt><span class="section"><a href="boost_optional/in_place_factories.html">In-Place Factories</a></span></dt>
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<dt><span class="section"><a href="boost_optional/a_note_about_optional_bool_.html">A note about
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optional<bool></a></span></dt>
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<dt><span class="section"><a href="boost_optional/exception_safety_guarantees.html">Exception Safety
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Guarantees</a></span></dt>
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<dt><span class="section"><a href="boost_optional/type_requirements.html">Type requirements</a></span></dt>
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<dt><span class="section"><a href="boost_optional/dependencies_and_portability.html">Dependencies
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and Portability</a></span></dt>
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<dd><dl><dt><span class="section"><a href="boost_optional/dependencies_and_portability.html#boost_optional.dependencies_and_portability.optional_reference_binding">Optional
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<dd><dl><dt><span class="section"><a href="boost_optional/dependencies_and_portability/optional_reference_binding.html">Optional
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Reference Binding</a></span></dt></dl></dd>
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<dt><span class="section"><a href="boost_optional/acknowledgments.html">Acknowledgments</a></span></dt>
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</dl>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
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<a name="optional.introduction"></a><a class="link" href="index.html#optional.introduction" title="Introduction">Introduction</a>
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</h2></div></div></div>
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<div class="toc"><dl class="toc">
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<dt><span class="section"><a href="index.html#optional.introduction.problem">Problem</a></span></dt>
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<dt><span class="section"><a href="index.html#optional.introduction.solution">Solution</a></span></dt>
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</dl></div>
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<h3>
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<a name="optional.h0"></a>
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<span class="phrase"><a name="optional.introduction"></a></span><a class="link" href="index.html#optional.introduction">Introduction</a>
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</h3>
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<p>
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Class template <code class="computeroutput"><span class="identifier">optional</span></code> is
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a wrapper for representing 'optional' (or 'nullable') objects who may not (yet)
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contain a valid value. Optional objects offer full value semantics; they are
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good for passing by value and usage inside STL containers. This is a header-only
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library.
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</p>
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<div class="section">
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<div class="titlepage"><div><div><h3 class="title">
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<a name="optional.introduction.problem"></a><a class="link" href="index.html#optional.introduction.problem" title="Problem">Problem</a>
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</h3></div></div></div>
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Class template <code class="computeroutput"><span class="identifier">optional</span></code> is a
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wrapper for representing 'optional' (or 'nullable') objects who may not (yet)
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contain a valid value. Optional objects offer full value semantics; they are
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good for passing by value and usage inside STL containers. This is a header-only
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library.
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</p>
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<h3>
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<a name="optional.h1"></a>
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<span class="phrase"><a name="optional.problem"></a></span><a class="link" href="index.html#optional.problem">Problem</a>
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</h3>
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<p>
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Suppose we want to read a parameter form a config file which represents some
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integral value, let's call it <code class="computeroutput"><span class="string">"MaxValue"</span></code>.
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It is possible that this parameter is not specified; such situation is no
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error. It is valid to not specify the parameter and in that case the program
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is supposed to behave slightly different. Also suppose that any possible
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value of type <code class="computeroutput"><span class="keyword">int</span></code> is a valid
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value for <code class="computeroutput"><span class="string">"MaxValue"</span></code>,
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so we cannot jut use <code class="computeroutput"><span class="special">-</span><span class="number">1</span></code>
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to represent the absence of the parameter in the config file.
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</p>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h3 class="title">
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<a name="optional.introduction.solution"></a><a class="link" href="index.html#optional.introduction.solution" title="Solution">Solution</a>
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</h3></div></div></div>
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Suppose we want to read a parameter form a config file which represents some
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integral value, let's call it <code class="computeroutput"><span class="string">"MaxValue"</span></code>.
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It is possible that this parameter is not specified; such situation is no error.
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It is valid to not specify the parameter and in that case the program is supposed
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to behave slightly different. Also suppose that any possible value of type <code class="computeroutput"><span class="keyword">int</span></code> is a valid value for <code class="computeroutput"><span class="string">"MaxValue"</span></code>,
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so we cannot jut use <code class="computeroutput"><span class="special">-</span><span class="number">1</span></code>
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to represent the absence of the parameter in the config file.
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</p>
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<h3>
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<a name="optional.h2"></a>
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<span class="phrase"><a name="optional.solution"></a></span><a class="link" href="index.html#optional.solution">Solution</a>
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</h3>
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<p>
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This is how you solve it with <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span></code>:
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</p>
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This is how you solve it with <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span></code>:
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</p>
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<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">optional</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
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<span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">getConfigParam</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">name</span><span class="special">);</span> <span class="comment">// return either an int or a `not-an-int`</span>
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@ -138,13 +111,11 @@
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<span class="special">}</span>
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</pre>
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</div>
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</div>
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</div>
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<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="left"><p><small>Last revised: June 03, 2014 at 14:35:30 GMT</small></p></td>
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<td align="left"><p><small>Last revised: June 04, 2014 at 16:06:37 GMT</small></p></td>
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