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| <h2><span class="refentrytitle">Struct template otherwise</span></h2> |
| <p>boost::proto::otherwise — |
| Syntactic sugar for <code class="computeroutput"><a class="link" href="when.html" title="Struct template when">proto::when</a>< <a class="link" href="_.html" title="Struct _">proto::_</a>, Fun ></code>, |
| for use in grammars to handle all the cases not yet handled. |
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| <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.when_hpp" title="Header <boost/proto/transform/when.hpp>">boost/proto/transform/when.hpp</a>> |
| |
| </span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Fun<span class="special">></span> |
| <span class="keyword">struct</span> <a class="link" href="otherwise.html" title="Struct template otherwise">otherwise</a> <span class="special">:</span> <span class="keyword"></span> <a class="link" href="when.html" title="Struct template when">proto::when</a><span class="special"><</span> <a class="link" href="_.html" title="Struct _">proto::_</a><span class="special">,</span> <span class="identifier">Fun</span> <span class="special">></span> <span class="special">{</span> |
| <span class="special">}</span><span class="special">;</span></pre></div> |
| <div class="refsect1"> |
| <a name="id2450142"></a><h2>Description</h2> |
| <p> |
| Use <code class="computeroutput">proto::otherwise<T></code> in your grammars as a synonym for |
| <code class="computeroutput"><a class="link" href="when.html" title="Struct template when">proto::when</a>< <a class="link" href="_.html" title="Struct _">proto::_</a>, Fun ></code> |
| as in the following transform which counts the number of terminals in an expression. |
| </p> |
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| </p> |
| <pre class="programlisting"><span class="comment">// Count the terminals in an expression tree.</span> |
| <span class="comment">// Must be invoked with initial state == mpl::int_<0>().</span> |
| <span class="keyword">struct</span> <span class="identifier">CountLeaves</span> <span class="special">:</span> |
| <a class="link" href="or_.html" title="Struct template or_">proto::or_</a><span class="special"><</span> |
| <span class="identifier">proto</span><span class="special">::</span><span class="identifier">when</span><span class="special"><</span><a class="link" href="terminal.html" title="Struct template terminal">proto::terminal</a><span class="special"><</span><a class="link" href="_.html" title="Struct _">proto::_</a><span class="special">></span><span class="special">,</span> <span class="identifier">mpl</span><span class="special">::</span><span class="identifier">next</span><span class="special"><</span><a class="link" href="_state.html" title="Struct _state">proto::_state</a><span class="special">></span><span class="special">(</span><span class="special">)</span><span class="special">></span><span class="special">,</span> |
| <span class="identifier">proto</span><span class="special">::</span><span class="identifier">otherwise</span><span class="special"><</span><a class="link" href="fold.html" title="Struct template fold">proto::fold</a><span class="special"><</span><a class="link" href="_.html" title="Struct _">proto::_</a><span class="special">,</span> <a class="link" href="_state.html" title="Struct _state">proto::_state</a><span class="special">,</span> <span class="identifier">CountLeaves</span><span class="special">></span> <span class="special">></span> |
| <span class="special">></span> |
| <span class="special">{</span><span class="special">}</span><span class="special">;</span></pre> |
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| <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>) |
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