boost_fusion/doc/html/fusion/functional/adapters/unfused.html

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<div class="section" title="unfused">
<div class="titlepage"><div><div><h4 class="title">
<a name="fusion.functional.adapters.unfused"></a><a class="link" href="unfused.html" title="unfused">unfused</a>
</h4></div></div></div>
<a name="fusion.functional.adapters.unfused.description"></a><h6>
<a name="id831491"></a>
          <a class="link" href="unfused.html#fusion.functional.adapters.unfused.description">Description</a>
        </h6>
<p>
          An n-ary <a class="link" href="../concepts/poly.html" title="Polymorphic Function Object">Polymorphic Function
          Object</a> adapter template for an unary <a class="link" href="../concepts/poly.html" title="Polymorphic Function Object">Polymorphic
          Function Object</a> target function. When called, its arguments are
          bundled to a <a class="link" href="../../sequence/concepts/random_access_sequence.html" title="Random Access Sequence">Random
          Access Sequence</a> of references that is passed to the target function
          object.
        </p>
<p>
          The nullary overload of the call operator can be removed by setting the
          second template parameter to <code class="computeroutput"><span class="keyword">false</span></code>,
          which is very useful if the result type computation would result in a compile
          error, otherwise (nullary call operator's prototypes can't be templates
          and thus are instantiated as early as the class template).
        </p>
<p>
          Only LValue arguments are accepted. To overcome this limitation, apply
          <a href="http://www.boost.org/libs/functional/forward/doc/html/index.html" target="_top">Boost.Functional/Forward</a>.
        </p>
<p>
          The type of the target function is allowed to be const qualified or a reference.
          Const qualification is preserved and propagated appropriately. In other
          words, only const versions of <code class="literal">operator()</code> can be used
          if the target function object is const - or, in case the target function
          object is held by value, the adapter is const.
        </p>
<a name="fusion.functional.adapters.unfused.header"></a><h6>
<a name="id831549"></a>
          <a class="link" href="unfused.html#fusion.functional.adapters.unfused.header">Header</a>
        </h6>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">functional</span><span class="special">/</span><span class="identifier">adapter</span><span class="special">/</span><span class="identifier">unfused</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
</pre>
<a name="fusion.functional.adapters.unfused.synopsis"></a><h6>
<a name="id831619"></a>
          <a class="link" href="unfused.html#fusion.functional.adapters.unfused.synopsis">Synopsis</a>
        </h6>
<pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Function</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">AllowNullary</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">&gt;</span>
<span class="keyword">class</span> <span class="identifier">unfused</span><span class="special">;</span>
</pre>
<a name="fusion.functional.adapters.unfused.template_parameters"></a><h6>
<a name="id831693"></a>
          <a class="link" href="unfused.html#fusion.functional.adapters.unfused.template_parameters">Template
          parameters</a>
        </h6>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                <p>
                  Parameter
                </p>
                </th>
<th>
                <p>
                  Description
                </p>
                </th>
<th>
                <p>
                  Default
                </p>
                </th>
</tr></thead>
<tbody>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">Function</span></code>
                </p>
                </td>
<td>
                <p>
                  A unary <a class="link" href="../concepts/poly.html" title="Polymorphic Function Object">Polymorphic
                  Function Object</a>
                </p>
                </td>
<td>
                <p>
                </p>
                </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">AllowNullary</span></code>
                </p>
                </td>
<td>
                <p>
                  Boolean constant
                </p>
                </td>
<td>
                <p>
                  true
                </p>
                </td>
</tr>
</tbody>
</table></div>
<a name="fusion.functional.adapters.unfused.model_of"></a><h6>
<a name="id833727"></a>
          <a class="link" href="unfused.html#fusion.functional.adapters.unfused.model_of">Model of</a>
        </h6>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem"><a class="link" href="../concepts/poly.html" title="Polymorphic Function Object">Polymorphic Function
            Object</a></li>
<li class="listitem"><a class="link" href="../concepts/def_callable.html" title="Deferred Callable Object">Deferred Callable
            Object</a></li>
</ul></div>
<div class="variablelist" title="Notation">
<p class="title"><b>Notation</b></p>
<dl>
<dt><span class="term"><code class="computeroutput"><span class="identifier">F</span></code></span></dt>
<dd><p>
              A possibly const qualified, unary <a class="link" href="../concepts/poly.html" title="Polymorphic Function Object">Polymorphic
              Function Object</a> type or reference type thereof
            </p></dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">f</span></code></span></dt>
<dd><p>
              An object convertible to <code class="computeroutput"><span class="identifier">F</span></code>
            </p></dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">UL</span></code></span></dt>
<dd><p>
              The type <code class="computeroutput"><span class="identifier">unfused</span><span class="special">&lt;</span><span class="identifier">F</span><span class="special">&gt;</span></code>
            </p></dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">ul</span></code></span></dt>
<dd><p>
              An instance of <code class="computeroutput"><span class="identifier">UL</span></code>,
              initialized with <code class="computeroutput"><span class="identifier">f</span></code>
            </p></dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">a0</span></code>...<code class="computeroutput"><span class="identifier">aN</span></code></span></dt>
<dd><p>
              Arguments to <code class="computeroutput"><span class="identifier">ul</span></code>
            </p></dd>
</dl>
</div>
<a name="fusion.functional.adapters.unfused.expression_semantics"></a><h6>
<a name="id833917"></a>
          <a class="link" href="unfused.html#fusion.functional.adapters.unfused.expression_semantics">Expression
          Semantics</a>
        </h6>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                <p>
                  Expression
                </p>
                </th>
<th>
                <p>
                  Semantics
                </p>
                </th>
</tr></thead>
<tbody>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">UL</span><span class="special">(</span><span class="identifier">f</span><span class="special">)</span></code>
                </p>
                </td>
<td>
                <p>
                  Creates a fused function as described above, initializes the target
                  function with <code class="computeroutput"><span class="identifier">f</span></code>.
                </p>
                </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">UL</span><span class="special">()</span></code>
                </p>
                </td>
<td>
                <p>
                  Creates a fused function as described above, attempts to use <code class="computeroutput"><span class="identifier">F</span></code>'s default constructor.
                </p>
                </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">ul</span><span class="special">(</span><span class="identifier">a0</span></code>...<code class="computeroutput"><span class="identifier">aN</span><span class="special">)</span></code>
                </p>
                </td>
<td>
                <p>
                  Calls <code class="computeroutput"><span class="identifier">f</span></code> with a
                  <a class="link" href="../../sequence.html" title="Sequence">Sequence</a> that contains references
                  to the arguments <code class="computeroutput"><span class="identifier">a0</span></code>...<code class="computeroutput"><span class="identifier">aN</span></code>.
                </p>
                </td>
</tr>
</tbody>
</table></div>
<a name="fusion.functional.adapters.unfused.example"></a><h6>
<a name="id834110"></a>
          <a class="link" href="unfused.html#fusion.functional.adapters.unfused.example">Example</a>
        </h6>
<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">fused_incrementer</span>
<span class="special">{</span>
    <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Seq</span><span class="special">&gt;</span>
    <span class="keyword">struct</span> <span class="identifier">result</span>
    <span class="special">{</span>
        <span class="keyword">typedef</span> <span class="keyword">void</span> <span class="identifier">type</span><span class="special">;</span>
    <span class="special">};</span>

    <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Seq</span><span class="special">&gt;</span>
    <span class="keyword">void</span> <span class="keyword">operator</span><span class="special">()(</span><span class="identifier">Seq</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">s</span><span class="special">)</span> <span class="keyword">const</span>
    <span class="special">{</span>
        <a class="link" href="../../algorithm/iteration/functions/for_each.html" title="for_each"><code class="computeroutput"><span class="identifier">for_each</span></code></a><span class="special">(</span><span class="identifier">s</span><span class="special">,++</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lambda</span><span class="special">::</span><span class="identifier">_1</span><span class="special">);</span>
    <span class="special">}</span>
<span class="special">};</span>

<span class="keyword">void</span> <span class="identifier">try_it</span><span class="special">()</span>
<span class="special">{</span>
    <span class="identifier">unfused</span><span class="special">&lt;</span><span class="identifier">fused_incrementer</span><span class="special">&gt;</span> <span class="identifier">increment</span><span class="special">;</span>
    <span class="keyword">int</span> <span class="identifier">a</span> <span class="special">=</span> <span class="number">2</span><span class="special">;</span> <span class="keyword">char</span> <span class="identifier">b</span> <span class="special">=</span> <span class="char">'X'</span><span class="special">;</span>
    <span class="identifier">increment</span><span class="special">(</span><span class="identifier">a</span><span class="special">,</span><span class="identifier">b</span><span class="special">);</span>
    <span class="identifier">assert</span><span class="special">(</span><span class="identifier">a</span> <span class="special">==</span> <span class="number">3</span> <span class="special">&amp;&amp;</span> <span class="identifier">b</span> <span class="special">==</span> <span class="char">'Y'</span><span class="special">);</span>
<span class="special">}</span>
</pre>
<a name="fusion.functional.adapters.unfused.see_also"></a><h6>
<a name="id834477"></a>
          <a class="link" href="unfused.html#fusion.functional.adapters.unfused.see_also">See also</a>
        </h6>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem"><a class="link" href="unfused_typed.html" title="unfused_typed"><code class="computeroutput"><span class="identifier">unfused_typed</span></code></a></li>
<li class="listitem"><a class="link" href="../generation/functions/mk_unfused.html" title="make_unfused"><code class="computeroutput"><span class="identifier">make_unfused</span></code></a></li>
</ul></div>
</div>
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<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright &#169; 2001-2007 Joel de Guzman, Dan Marsden, Tobias
      Schwinger<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></td>
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