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<div class="refentry" title="Struct template otherwise">
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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="emphasis"><em>// 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>>
</em></span><span class="bold"><strong>template</strong></span><<span class="bold"><strong>typename</strong></span> Fun>
<span class="bold"><strong>struct</strong></span> <a class="link" href="otherwise.html" title="Struct template otherwise">otherwise</a> : <span class="bold"><strong></strong></span> <a class="link" href="when.html" title="Struct template when">proto::when</a>< <a class="link" href="_.html" title="Struct _">proto::_</a>, Fun > {
};</pre></div>
<div class="refsect1" title="Description">
<a name="id1678713"></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.
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<pre class="programlisting">// Count the terminals in an expression tree.
// Must be invoked with initial state == mpl::int_<0>().
struct CountLeaves :
<a class="link" href="or_.html" title="Struct template or_">proto::or_</a><
proto::when<<a class="link" href="terminal.html" title="Struct template terminal">proto::terminal</a><<a class="link" href="_.html" title="Struct _">proto::_</a>>, mpl::next<<a class="link" href="_state.html" title="Struct _state">proto::_state</a>>()>,
proto::otherwise<<a class="link" href="fold.html" title="Struct template fold">proto::fold</a><<a class="link" href="_.html" title="Struct _">proto::_</a>, <a class="link" href="_state.html" title="Struct _state">proto::_state</a>, CountLeaves> >
>
{};</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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