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| <a name="phoenix.actors"></a><a class="link" href="actors.html" title="Actors">Actors</a> |
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| <p> |
| The <code class="computeroutput"><span class="identifier">Actor</span></code> is the main concept |
| behind the library. Actors are function objects. An actor can accept 0 to |
| <code class="computeroutput"><span class="identifier">PHOENIX_LIMIT</span></code> arguments. |
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| You can set <code class="computeroutput"><span class="identifier">PHOENIX_LIMIT</span></code>, |
| the predefined maximum arity an actor can take. By default, <code class="computeroutput"><span class="identifier">PHOENIX_LIMIT</span></code> is set to 10. |
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| <p> |
| Phoenix supplies an <code class="computeroutput"><span class="identifier">actor</span></code> class |
| template whose specializations model the <code class="computeroutput"><span class="identifier">Actor</span></code> |
| concept. <code class="computeroutput"><span class="identifier">actor</span></code> has one template |
| parameter, <code class="computeroutput"><span class="identifier">Eval</span></code>, that supplies |
| the smarts to evaluate the resulting function. |
| </p> |
| <pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Eval</span><span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">actor</span> <span class="special">:</span> <span class="identifier">Eval</span> |
| <span class="special">{</span> |
| <span class="identifier">return_type</span> |
| <span class="keyword">operator</span><span class="special">()()</span> <span class="keyword">const</span><span class="special">;</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T0</span><span class="special">></span> |
| <span class="identifier">return_type</span> |
| <span class="keyword">operator</span><span class="special">()(</span><span class="identifier">T0</span><span class="special">&</span> <span class="identifier">_0</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T0</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">T1</span><span class="special">></span> |
| <span class="identifier">return_type</span> |
| <span class="keyword">operator</span><span class="special">()(</span><span class="identifier">T0</span><span class="special">&</span> <span class="identifier">_0</span><span class="special">,</span> <span class="identifier">T1</span><span class="special">&</span> <span class="identifier">_1</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> |
| |
| <span class="comment">//... |
| </span><span class="special">};</span> |
| </pre> |
| <p> |
| The actor class accepts the arguments through a set of function call operators |
| for 0 to <code class="computeroutput"><span class="identifier">PHOENIX_LIMIT</span></code> arities |
| (Don't worry about the details, for now. Note, for example, that we skimp over |
| the details regarding <code class="computeroutput"><span class="identifier">return_type</span></code>). |
| The arguments are then forwarded to the actor's <code class="computeroutput"><span class="identifier">Eval</span></code> |
| for evaluation. |
| </p> |
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| <td align="right"><div class="copyright-footer">Copyright © 2002-2005 Joel |
| de Guzman, Dan Marsden<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>) |
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