hana/test/concept/struct/fold_left.cpp
2017-01-07 14:14:18 -08:00

60 lines
1.8 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)
#include <boost/hana/assert.hpp>
#include <boost/hana/concept/struct.hpp>
#include <boost/hana/equal.hpp>
#include <boost/hana/fold_left.hpp>
#include <boost/hana/integral_constant.hpp>
#include "minimal_struct.hpp"
#include <laws/base.hpp>
#include <support/minimal_product.hpp>
namespace hana = boost::hana;
using hana::test::ct_eq;
template <int i = 0>
struct undefined { };
struct MoveOnly {
MoveOnly() = default;
MoveOnly(MoveOnly&&) = default;
MoveOnly(MoveOnly const&) = delete;
MoveOnly& operator=(MoveOnly&&) = default;
MoveOnly& operator=(MoveOnly const&) = delete;
};
int main() {
constexpr auto pair = ::minimal_product;
ct_eq<999> s{};
hana::test::_injection<0> f{};
BOOST_HANA_CONSTANT_CHECK(hana::equal(
hana::fold_left(obj(), s, undefined<>{}),
s
));
BOOST_HANA_CONSTANT_CHECK(hana::equal(
hana::fold_left(obj(ct_eq<0>{}), s, f),
f(s, pair(hana::int_c<0>, ct_eq<0>{}))
));
BOOST_HANA_CONSTANT_CHECK(hana::equal(
hana::fold_left(obj(ct_eq<0>{}, ct_eq<1>{}), s, f),
f(f(s, pair(hana::int_c<0>, ct_eq<0>{})), pair(hana::int_c<1>, ct_eq<1>{}))
));
BOOST_HANA_CONSTANT_CHECK(hana::equal(
hana::fold_left(obj(ct_eq<0>{}, ct_eq<1>{}, ct_eq<2>{}), s, f),
f(f(f(s, pair(hana::int_c<0>, ct_eq<0>{})),
pair(hana::int_c<1>, ct_eq<1>{})),
pair(hana::int_c<2>, ct_eq<2>{}))
));
// fold_left with move-only members
hana::fold_left(obj(MoveOnly{}), 0, [](int, auto) { return 0; });
hana::fold_left(obj(MoveOnly{}, MoveOnly{}), 0, [](int, auto) { return 0; });
}