<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>Function as_child</title> <link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.78.1"> <link rel="home" href="../../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> <link rel="up" href="../../proto/reference.html#header.boost.proto.traits_hpp" title="Header <boost/proto/traits.hpp>"> <link rel="prev" href="as_expr_idm45506991005376.html" title="Function as_expr"> <link rel="next" href="child_idm45506990961392.html" title="Function child"> </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 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class="titlepage"></div> <div class="refnamediv"> <h2><span class="refentrytitle">Function as_child</span></h2> <p>boost::proto::as_child — A function that wraps non-Proto objects in Proto terminals (by reference) and leaves Proto expression types alone.</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.traits_hpp" title="Header <boost/proto/traits.hpp>">boost/proto/traits.hpp</a>> </span> <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> <span class="keyword">typename</span> <a class="link" href="result_of/as_child.html" title="Struct template as_child">proto::result_of::as_child</a><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span><span class="special">::</span><span class="identifier">type</span> <span class="identifier">as_child</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&</span> t<span class="special">)</span><span class="special">;</span> <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> <span class="keyword">typename</span> <a class="link" href="result_of/as_child.html" title="Struct template as_child">proto::result_of::as_child</a><span class="special"><</span> <span class="identifier">T</span> <span class="keyword">const</span> <span class="special">></span><span class="special">::</span><span class="identifier">type</span> <span class="identifier">as_child</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&</span> t<span class="special">)</span><span class="special">;</span> <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <a class="link" href="../../Domain.html" title="Concept Domain">Domain</a><span class="special">,</span> <span class="keyword">typename</span> T<span class="special">></span> <span class="keyword">typename</span> <a class="link" href="result_of/as_child.html" title="Struct template as_child">proto::result_of::as_child</a><span class="special"><</span> <span class="identifier">T</span><span class="special">,</span> <span class="identifier">Domain</span> <span class="special">></span><span class="special">::</span><span class="identifier">type</span> <span class="identifier">as_child</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&</span> t<span class="special">)</span><span class="special">;</span> <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <a class="link" href="../../Domain.html" title="Concept Domain">Domain</a><span class="special">,</span> <span class="keyword">typename</span> T<span class="special">></span> <span class="keyword">typename</span> <a class="link" href="result_of/as_child.html" title="Struct template as_child">proto::result_of::as_child</a><span class="special"><</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">,</span> <span class="identifier">Domain</span> <span class="special">></span><span class="special">::</span><span class="identifier">type</span> <span class="identifier">as_child</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&</span> t<span class="special">)</span><span class="special">;</span></pre></div> <div class="refsect1"> <a name="idm45555175737216"></a><h2>Description</h2> <p> The <code class="computeroutput">proto::as_child()</code> function returns Proto expression objects that are suitable for storage as child nodes in an expression tree. It turns non-Proto objects into Proto terminals. Its behavior is domain-specific. By default, non-Proto types are held wrapped by reference in a new Proto terminal expression, and objects that are already Proto expressions are simply returned by reference. </p> <p> If <code class="computeroutput">Domain</code> is not explicitly specified, it is assumed to be <code class="computeroutput"><code class="computeroutput"><a class="link" href="default_domain.html" title="Struct default_domain">proto::default_domain</a></code></code>. </p> <p> See <code class="computeroutput"><code class="computeroutput"><a class="link" href="domain/as_child.html" title="Struct template as_child">proto::domain::as_child</a></code><></code> for a complete description of this function's default behavior. </p> <div class="variablelist"><table border="0" class="variablelist compact"> <colgroup> <col align="left" valign="top"> <col> </colgroup> <tbody><tr> <td><p><span class="term">Returns:</span></p></td> <td><code class="computeroutput">typename Domain::template as_child< T >()(t)</code></td> </tr></tbody> </table></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> <hr> <div class="spirit-nav"> <a accesskey="p" href="as_expr_idm45506991005376.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../proto/reference.html#header.boost.proto.traits_hpp"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="child_idm45506990961392.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html>