64 lines
1.6 KiB
Plaintext
64 lines
1.6 KiB
Plaintext
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/*==============================================================================
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Copyright (c) 2005-2010 Joel de Guzman
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Copyright (c) 2015 John Fletcher
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#ifndef BOOST_PHOENIX_CORE_IS_VALUE_HPP
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#define BOOST_PHOENIX_CORE_IS_VALUE_HPP
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#include <boost/mpl/bool.hpp>
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// Copied from is_actor.hpp
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// Note to Thomas and any future maintainer: please make this as
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// lightweight as possible (as it is right now).
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namespace boost { namespace phoenix
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{
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///////////////////////////////////////////////////////////////////////////////
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//
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// is_value<T>
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//
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// Tests if T is a value. Evaluates to mpl::true_ or mpl::false_
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//
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///////////////////////////////////////////////////////////////////////////////
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namespace expression {
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template <typename T>
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struct value;
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}
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template <typename T, typename Enable = void>
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struct is_value
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: mpl::false_
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{};
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template <typename T>
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struct is_value<T const>
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: is_value<T>
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{};
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template <typename T>
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struct is_value<T &>
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: is_value<T>
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{};
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// This does not seem to work.
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// There is an alternative in value.hpp which does work.
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template <typename T>
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struct is_value< expression::value<T> >
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: mpl::true_
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{};
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template <typename T>
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bool is_val(T const & /* t */)
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{
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return is_value<T>::value;
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}
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}}
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#endif
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