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