1// Copyright Louis Dionne 2013-2022
2// Distributed under the Boost Software License, Version 1.0.
3// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
4
5#include <boost/hana/assert.hpp>
6#include <boost/hana/equal.hpp>
7#include <boost/hana/experimental/view.hpp>
8#include <boost/hana/integral_constant.hpp>
9#include <boost/hana/length.hpp>
10#include <boost/hana/tuple.hpp>
11
12#include <support/seq.hpp>
13namespace hana = boost::hana;
14
15
16template <int> struct undefined { };
17
18int main() {
19 auto container = ::seq;
20
21 {
22 auto storage = container();
23 auto sliced = hana::experimental::sliced(storage, hana::tuple_c<int>);
24 BOOST_HANA_CONSTANT_CHECK(hana::equal(
25 hana::length(sliced),
26 hana::size_c<0>
27 ));
28 }
29
30 {
31 auto storage = container(undefined<0>{});
32 auto sliced = hana::experimental::sliced(storage, hana::tuple_c<int, 0>);
33 BOOST_HANA_CONSTANT_CHECK(hana::equal(
34 hana::length(sliced),
35 hana::size_c<1>
36 ));
37 }{
38 auto storage = container(undefined<0>{});
39 auto sliced = hana::experimental::sliced(storage, hana::tuple_c<int>);
40 BOOST_HANA_CONSTANT_CHECK(hana::equal(
41 hana::length(sliced),
42 hana::size_c<0>
43 ));
44 }
45
46 {
47 auto storage = container(undefined<0>{}, undefined<1>{});
48 auto sliced = hana::experimental::sliced(storage, hana::tuple_c<int, 0>);
49 BOOST_HANA_CONSTANT_CHECK(hana::equal(
50 hana::length(sliced),
51 hana::size_c<1>
52 ));
53 }{
54 auto storage = container(undefined<0>{}, undefined<1>{});
55 auto sliced = hana::experimental::sliced(storage, hana::tuple_c<int, 0, 1>);
56 BOOST_HANA_CONSTANT_CHECK(hana::equal(
57 hana::length(sliced),
58 hana::size_c<2>
59 ));
60 }{
61 auto storage = container(undefined<0>{}, undefined<1>{});
62 auto sliced = hana::experimental::sliced(storage, hana::tuple_c<int, 0, 0>);
63 BOOST_HANA_CONSTANT_CHECK(hana::equal(
64 hana::length(sliced),
65 hana::size_c<2>
66 ));
67 }
68}
69

source code of boost/libs/hana/test/experimental/view/sliced/length.cpp