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// 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/integral_constant.hpp>
#include <boost/hana/less.hpp>
#include <boost/hana/lexicographical_compare.hpp>
#include <boost/hana/tuple.hpp>
#include <boost/hana/type.hpp>
namespace hana = boost::hana;
int main() {
// works with elements whose `less` does not return a Constant
{
constexpr auto xs = hana::make_tuple(1, 2, 3, 4);
constexpr auto ys = hana::make_tuple(1, 6, 3, 4);
static_assert(hana::lexicographical_compare(xs, ys), "");
}
// and with those that do
{
auto xs = hana::make_tuple(hana::int_c<1>, hana::int_c<2>, hana::int_c<3>);
auto ys = hana::make_tuple(hana::int_c<1>, hana::int_c<5>, hana::int_c<3>);
BOOST_HANA_CONSTANT_CHECK(hana::lexicographical_compare(xs, ys));
}
// it also accepts a custom predicate
{
auto xs = hana::make_tuple(hana::type_c<int>, hana::type_c<char>, hana::type_c<void*>);
auto ys = hana::make_tuple(hana::type_c<int>, hana::type_c<long>, hana::type_c<void*>);
BOOST_HANA_CONSTANT_CHECK(
hana::lexicographical_compare(xs, ys, [](auto t, auto u) {
return hana::sizeof_(t) < hana::sizeof_(u);
})
);
}
}
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