hana/test/_include/laws/comonad.hpp
2017-01-07 14:14:18 -08:00

54 lines
1.7 KiB
C++

// Copyright Louis Dionne 2013-2017
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
#ifndef BOOST_HANA_TEST_LAWS_COMONAD_HPP
#define BOOST_HANA_TEST_LAWS_COMONAD_HPP
#include <boost/hana/assert.hpp>
#include <boost/hana/concept/comonad.hpp>
#include <boost/hana/concept/comparable.hpp>
#include <boost/hana/core/when.hpp>
#include <boost/hana/concept/foldable.hpp>
#include <boost/hana/concept/functor.hpp>
#include <laws/base.hpp>
namespace boost { namespace hana { namespace test {
template <typename W, typename = when<true>>
struct TestComonad : TestComonad<W, laws> {
using TestComonad<W, laws>::TestComonad;
};
template <typename W>
struct TestComonad<W, laws> {
template <typename Ws>
TestComonad(Ws ws) {
hana::for_each(ws, [](auto w) {
static_assert(Comonad<decltype(w)>{}, "");
// extract(duplicate(w)) == w
BOOST_HANA_CHECK(hana::equal(
hana::extract(hana::duplicate(w)),
w
));
// transform(duplicate(w), extract) == w
BOOST_HANA_CHECK(hana::equal(
hana::transform(hana::duplicate(w), extract),
w
));
// duplicate(duplicate(w)) == transform(duplicate(w), duplicate)
BOOST_HANA_CHECK(hana::equal(
hana::duplicate(hana::duplicate(w)),
hana::transform(hana::duplicate(w), duplicate)
));
});
}
};
}}} // end namespace boost::hana::test
#endif // !BOOST_HANA_TEST_LAWS_COMONAD_HPP