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| <a name="boost.proto.make.impl"></a><div class="titlepage"></div> |
| <div class="refnamediv"> |
| <h2><span class="refentrytitle">Struct template impl</span></h2> |
| <p>boost::proto::make::impl</p> |
| </div> |
| <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> |
| <div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../../../proto/reference.html#header.boost.proto.transform.make_hpp" title="Header <boost/proto/transform/make.hpp>">boost/proto/transform/make.hpp</a>> |
| |
| </span> |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <a class="link" href="../../../Expr.html" title="Concept Expr">Expr</a><span class="special">,</span> <span class="keyword">typename</span> State<span class="special">,</span> <span class="keyword">typename</span> Data<span class="special">></span> |
| <span class="keyword">struct</span> <a class="link" href="impl.html" title="Struct template impl">impl</a> <span class="special">:</span> <span class="keyword"></span> <a class="link" href="../transform_impl.html" title="Struct template transform_impl">proto::transform_impl</a><span class="special"><</span> <span class="identifier">Expr</span><span class="special">,</span> <span class="identifier">State</span><span class="special">,</span> <span class="identifier">Data</span> <span class="special">></span> <span class="special">{</span> |
| <span class="comment">// <a class="link" href="impl.html#boost.proto.make.impltypes">types</a></span> |
| <span class="keyword">typedef</span> <span class="emphasis"><em><span class="identifier">see</span><span class="special">-</span><span class="identifier">below</span></em></span> <a class="link" href="impl.html#boost.proto.make.impl.result_type"><span class="identifier">result_type</span></a><span class="special">;</span> |
| |
| <span class="comment">// <a class="link" href="impl.html#id1296062-bb">public member functions</a></span> |
| <span class="identifier">result_type</span> <a class="link" href="impl.html#id1296067-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="keyword">typename</span> <span class="identifier">impl</span><span class="special">::</span><span class="identifier">expr_param</span><span class="special">,</span> |
| <span class="keyword">typename</span> <span class="identifier">impl</span><span class="special">::</span><span class="identifier">state_param</span><span class="special">,</span> |
| <span class="keyword">typename</span> <span class="identifier">impl</span><span class="special">::</span><span class="identifier">data_param</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> |
| <span class="special">}</span><span class="special">;</span></pre></div> |
| <div class="refsect1"> |
| <a name="id2442540"></a><h2>Description</h2> |
| <div class="refsect2"> |
| <a name="id2442544"></a><h3> |
| <a name="boost.proto.make.impltypes"></a><code class="computeroutput">impl</code> |
| public |
| types</h3> |
| <div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> |
| <p> |
| <span class="keyword">typedef</span> <span class="emphasis"><em><span class="identifier">see</span><span class="special">-</span><span class="identifier">below</span></em></span> <a name="boost.proto.make.impl.result_type"></a><span class="identifier">result_type</span><span class="special">;</span></p> |
| <p> |
| <code class="computeroutput"><a class="link" href="../make.html" title="Struct template make">proto::make</a><T>::impl<Expr, State, Data>::result_type</code> is |
| computed as follows: |
| </p> |
| <p> |
| If <code class="computeroutput">T</code> is an <a class="link" href="../../../ObjectTransform.html" title="Concept ObjectTransform">ObjectTransform</a> of the form |
| <code class="computeroutput">Object(A<sub>0</sub>,...A<sub>n</sub>)</code>, |
| then let <code class="computeroutput">O</code> be the return type |
| <code class="computeroutput">Object</code>. Otherwise, let <code class="computeroutput">O</code> |
| be <code class="computeroutput">T</code>. The <code class="computeroutput">result_type</code> typedef is |
| then computed as follows: |
| </p> |
| <p> |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"><p> |
| If <code class="computeroutput">O</code> is a <a class="link" href="../../../Transform.html" title="Concept Transform">Transform</a>, then let |
| the result type be |
| <code class="computeroutput"> |
| boost::result_of<<a class="link" href="../when.html" title="Struct template when">proto::when</a><<a class="link" href="../_.html" title="Struct _">_</a>, O>(Expr, State, Data)>::type |
| </code>. |
| Note that a substitution took place. |
| </p></li> |
| <li class="listitem"> |
| If <code class="computeroutput">O</code> is a template like |
| <code class="computeroutput"><a class="link" href="../noinvoke.html" title="Struct template noinvoke">proto::noinvoke</a><S<X<sub>0</sub>,...X<sub>n</sub>> ></code>, |
| then the result type is calculated as follows: |
| <div class="itemizedlist"><ul class="itemizedlist" type="circle"> |
| <li class="listitem"><p> |
| For each <code class="computeroutput">i</code> in |
| <code class="computeroutput">[0,n]</code>, let <code class="computeroutput"> |
| X<sub>i</sub>' |
| </code> be |
| <code class="computeroutput"> |
| boost::result_of<<a class="link" href="../make.html" title="Struct template make">proto::make</a><X<sub>i</sub>>(Expr, State, Data)>::type |
| </code> |
| (which evaluates this procedure recursively). Note that a substitution took place. (In this case, |
| Proto merely assumes that a substitution took place for the sake of compile-time efficiency. There |
| would be no reason to use <code class="computeroutput"><a class="link" href="../noinvoke.html" title="Struct template noinvoke">proto::noinvoke<></a></code> |
| otherwise.) |
| </p></li> |
| <li class="listitem"><p> |
| The result type is |
| <code class="computeroutput"> |
| S<X<sub>0</sub>',...X<sub>n</sub>'> |
| </code>. |
| </p></li> |
| </ul></div> |
| </li> |
| <li class="listitem"> |
| If <code class="computeroutput">O</code> is a template like |
| <code class="computeroutput">S<X<sub>0</sub>,...X<sub>n</sub>></code>, |
| then the result type is calculated as follows: |
| <div class="itemizedlist"><ul class="itemizedlist" type="circle"> |
| <li class="listitem"><p> |
| For each <code class="computeroutput">i</code> in |
| <code class="computeroutput">[0,n]</code>, let <code class="computeroutput"> |
| X<sub>i</sub>' |
| </code> be |
| <code class="computeroutput"> |
| boost::result_of<<a class="link" href="../make.html" title="Struct template make">proto::make</a><X<sub>i</sub>>(Expr, State, Data)>::type |
| </code> |
| (which evaluates this procedure recursively). Note whether any substitutions took place during |
| this operation. |
| </p></li> |
| <li class="listitem"><p> |
| If any substitutions took place in the above step and |
| <code class="computeroutput"> |
| S<X<sub>0</sub>',...X<sub>n</sub>'> |
| </code> has a nested |
| <code class="computeroutput">type</code> typedef, the result type is |
| <code class="computeroutput"> |
| S<X<sub>0</sub>',...X<sub>n</sub>'>::type |
| </code>. |
| </p></li> |
| <li class="listitem"><p> |
| Otherwise, the result type is |
| <code class="computeroutput"> |
| S<X<sub>0</sub>',...X<sub>n</sub>'> |
| </code>. |
| </p></li> |
| </ul></div> |
| </li> |
| <li class="listitem"> |
| Otherwise, the result type is <code class="computeroutput">O</code>, and note that no |
| substitution took place. |
| </li> |
| </ul></div> |
| <p> |
| </p> |
| <p> |
| Note that <code class="computeroutput"><a class="link" href="../when.html" title="Struct template when">proto::when<></a></code> is implemented |
| in terms of <code class="computeroutput"><a class="link" href="../call.html" title="Struct template call">proto::call<></a></code> |
| and <code class="computeroutput"><a class="link" href="../make.html" title="Struct template make">proto::make<></a></code>, so the |
| above procedure is evaluated recursively. |
| </p> |
| </li></ol></div> |
| </div> |
| <div class="refsect2"> |
| <a name="id2443051"></a><h3> |
| <a name="id1296062-bb"></a><code class="computeroutput">impl</code> public member functions</h3> |
| <div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> |
| <pre class="literallayout"><span class="identifier">result_type</span> <a name="id1296067-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="keyword">typename</span> <span class="identifier">impl</span><span class="special">::</span><span class="identifier">expr_param</span> expr<span class="special">,</span> |
| <span class="keyword">typename</span> <span class="identifier">impl</span><span class="special">::</span><span class="identifier">state_param</span> state<span class="special">,</span> |
| <span class="keyword">typename</span> <span class="identifier">impl</span><span class="special">::</span><span class="identifier">data_param</span> data<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> |
| <p> |
| <code class="computeroutput"> |
| <code class="computeroutput"><a class="link" href="../make.html" title="Struct template make">proto::make</a></code><T>::impl<Expr,State,Data>::operator() |
| </code> |
| behaves as follows: |
| </p> |
| <p> |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"> |
| <p> |
| If <code class="computeroutput">T</code> is of the form |
| <code class="computeroutput">O(A<sub>0</sub>,...A<sub>n</sub>)</code>, then: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" type="circle"> |
| <li class="listitem"> |
| <p> |
| If <code class="computeroutput"> |
| <code class="computeroutput"><a class="link" href="../is_aggregate.html" title="Struct template is_aggregate">proto::is_aggregate</a></code><result_type>::value |
| </code> is <code class="computeroutput">true</code>, then construct |
| and return an object <code class="computeroutput">that</code> as follows: |
| </p> |
| <pre class="programlisting">result_type that = { |
| <code class="computeroutput"><a class="link" href="../when.html" title="Struct template when">proto::when</a></code><<code class="computeroutput"><a class="link" href="../_.html" title="Struct _">_</a></code>, A<sub>0</sub>>()(expr, state, data), |
| ... |
| <code class="computeroutput"><a class="link" href="../when.html" title="Struct template when">proto::when</a></code><<code class="computeroutput"><a class="link" href="../_.html" title="Struct _">_</a></code>, A<sub>n</sub>>()(expr, state, data) |
| };</pre> |
| <p> |
| </p> |
| </li> |
| <li class="listitem"> |
| <p> |
| Otherwise, construct |
| and return an object <code class="computeroutput">that</code> as follows: |
| </p> |
| <pre class="programlisting">result_type that( |
| <code class="computeroutput"><a class="link" href="../when.html" title="Struct template when">proto::when</a></code><<code class="computeroutput"><a class="link" href="../_.html" title="Struct _">_</a></code>, A<sub>0</sub>>()(expr, state, data), |
| ... |
| <code class="computeroutput"><a class="link" href="../when.html" title="Struct template when">proto::when</a></code><<code class="computeroutput"><a class="link" href="../_.html" title="Struct _">_</a></code>, A<sub>n</sub>>()(expr, state, data) |
| );</pre> |
| <p> |
| </p> |
| </li> |
| </ul></div> |
| </li> |
| <li class="listitem"> |
| <p> |
| Otherwise, construct |
| and return an object <code class="computeroutput">that</code> as follows: |
| </p> |
| <pre class="programlisting">result_type that = result_type();</pre> |
| <p> |
| </p> |
| </li> |
| </ul></div> |
| <p> |
| </p> |
| </li></ol></div> |
| </div> |
| </div> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2008 Eric Niebler<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> |
| </tr></table> |
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