key_is_multipliable.hpp

/* Copyright 2009-2017 Francesco Biscani (bluescarni@gmail.com)

This file is part of the Piranha library.

The Piranha library is free software; you can redistribute it and/or modify
it under the terms of either:

  * the GNU Lesser General Public License as published by the Free
    Software Foundation; either version 3 of the License, or (at your
    option) any later version.

or

  * the GNU General Public License as published by the Free Software
    Foundation; either version 3 of the License, or (at your option) any
    later version.

or both in parallel, as here.

The Piranha library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received copies of the GNU General Public License and the
GNU Lesser General Public License along with the Piranha library.  If not,
see https://www.gnu.org/licenses/. */

#ifndef PIRANHA_KEY_IS_MULTIPLIABLE_HPP
#define PIRANHA_KEY_IS_MULTIPLIABLE_HPP

#include <array>
#include <cstddef>
#include <type_traits>
#include <utility>

#include <piranha/is_cf.hpp>
#include <piranha/is_key.hpp>
#include <piranha/symbol_utils.hpp>
#include <piranha/term.hpp>
#include <piranha/type_traits.hpp>

namespace piranha
{

inline namespace impl
{

template <typename Cf, typename Key, typename = void>
struct key_is_multipliable_impl : std::false_type {
};

template <typename Cf, typename Key>
struct key_is_multipliable_impl<Cf, Key,
                                enable_if_t<std::is_same<const std::size_t, decltype(Key::multiply_arity)>::value
                                            && (Key::multiply_arity > 0u)>> {
    template <typename Cf1, typename Key1>
    using multiply_t
        = decltype(Key1::multiply(std::declval<std::array<term<Cf1, Key1>, Key1::multiply_arity> &>(),
                                  std::declval<const term<Cf1, Key1> &>(), std::declval<const term<Cf1, Key1> &>(),
                                  std::declval<const symbol_fset &>()));
    static const bool value = is_detected<multiply_t, Cf, Key>::value;
};
}


template <typename Cf, typename Key>
class key_is_multipliable
{
    PIRANHA_TT_CHECK(is_cf, uncvref_t<Cf>);
    PIRANHA_TT_CHECK(is_key, uncvref_t<Key>);
    static const bool implementation_defined = key_is_multipliable_impl<uncvref_t<Cf>, uncvref_t<Key>>::value;

public:
    static const bool value = implementation_defined;
};

template <typename Cf, typename Key>
const bool key_is_multipliable<Cf, Key>::value;
}

#endif