relational.hpp

/*
 * Boost Software License - Version 1.0 - August 17th, 2003
 *
 * Permission is hereby granted, free of charge, to any person or organization
 * obtaining a copy of the software and accompanying documentation covered by
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 * Software, and to permit third-parties to whom the Software is furnished to
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 *
 * The copyright notices in the Software and this entire statement, including
 * the above license grant, this restriction and the following disclaimer,
 * must be included in all copies of the Software, in whole or in part, and
 * all derivative works of the Software, unless such copies or derivative
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 * a source language processor.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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#ifndef VARIANT_RELATIONAL_HPP
#define VARIANT_RELATIONAL_HPP

#include <type_traits>

namespace detail
{

// These will be replaced by C++1z fold expressions when available
template<class ... Args>
using and_ = std::is_same<
    std::integer_sequence<bool, Args::value ... >,
    std::integer_sequence<bool, std::conditional_t< true, bool, Args >(true) ... > >;

template<class T>
using not_ = std::integral_constant<bool, !T::value>;
    
template<class ... Args>
using or_ = not_<std::is_same<
    std::integer_sequence<bool, Args::value ... >,
    std::integer_sequence<bool, std::conditional_t< true, bool, Args >(false) ... > > >;
}

#endif //VARIANT_RELATIONAL_HPP