rec/fplus/internal/compare.hpp
2020-03-18 14:42:46 +08:00

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// Copyright 2015, Tobias Hermann and the FunctionalPlus contributors.
// https://github.com/Dobiasd/FunctionalPlus
// 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)
#pragma once
#include <type_traits>
#include <fplus/internal/asserts/functions.hpp>
#include <fplus/internal/invoke.hpp>
namespace fplus
{
namespace internal
{
template <typename Compare>
auto ord_to_impl(Compare comp)
{
return [comp](auto x, auto y)
{
static_assert(std::is_same<decltype(x), decltype(y)>::value,
"Argument types must be the same");
using In = decltype(x);
internal::trigger_static_asserts<internal::binary_predicate_tag, Compare, In, In>();
using CompareOut = std::decay_t<internal::invoke_result_t<Compare, In, In>>;
static_assert(std::is_same<CompareOut, bool>::value,
"Function must return bool.");
return std::make_pair(internal::invoke(comp, x, y),
internal::invoke(comp, y, x));
};
}
}
}