span.cpp
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// Copyright Louis Dionne 2013-2022
// 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/equal.hpp>
#include <boost/hana/integral_constant.hpp>
#include <boost/hana/less.hpp>
#include <boost/hana/pair.hpp>
#include <boost/hana/span.hpp>
#include <boost/hana/tuple.hpp>
namespace hana = boost::hana;
constexpr auto xs = hana::make_tuple(hana::int_c<1>, hana::int_c<2>, hana::int_c<3>, hana::int_c<4>);
BOOST_HANA_CONSTANT_CHECK(
hana::span(xs, hana::less.than(hana::int_c<3>))
==
hana::make_pair(hana::make_tuple(hana::int_c<1>, hana::int_c<2>),
hana::make_tuple(hana::int_c<3>, hana::int_c<4>))
);
BOOST_HANA_CONSTANT_CHECK(
hana::span(xs, hana::less.than(hana::int_c<0>))
==
hana::make_pair(hana::make_tuple(), xs)
);
BOOST_HANA_CONSTANT_CHECK(
hana::span(xs, hana::less.than(hana::int_c<5>))
==
hana::make_pair(xs, hana::make_tuple())
);
// span.by is syntactic sugar
BOOST_HANA_CONSTANT_CHECK(
hana::span.by(hana::less.than(hana::int_c<3>), xs)
==
hana::make_pair(hana::make_tuple(hana::int_c<1>, hana::int_c<2>),
hana::make_tuple(hana::int_c<3>, hana::int_c<4>))
);
int main() { }