hana/example/optional/monad_plus.cpp
2017-01-07 14:14:18 -08:00

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731 B
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/concat.hpp>
#include <boost/hana/empty.hpp>
#include <boost/hana/equal.hpp>
#include <boost/hana/optional.hpp>
namespace hana = boost::hana;
static_assert(hana::concat(hana::nothing, hana::just('x')) == hana::just('x'), "");
BOOST_HANA_CONSTANT_CHECK(hana::concat(hana::nothing, hana::nothing) == hana::nothing);
static_assert(hana::concat(hana::just('x'), hana::just('y')) == hana::just('x'), "");
BOOST_HANA_CONSTANT_CHECK(hana::empty<hana::optional_tag>() == hana::nothing);
int main() { }