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/scan_left.hpp> |
8 | #include <boost/hana/tuple.hpp> |
9 | |
10 | #include <sstream> |
11 | namespace hana = boost::hana; |
12 | |
13 | |
14 | auto to_string = [](auto x) { |
15 | std::ostringstream ss; |
16 | ss << x; |
17 | return ss.str(); |
18 | }; |
19 | |
20 | auto f = [](auto state, auto element) { |
21 | return "f("+ to_string(state) + ", "+ to_string(element) + ")"; |
22 | }; |
23 | |
24 | int main() { |
25 | // with initial state |
26 | BOOST_HANA_RUNTIME_CHECK(hana::scan_left(hana::make_tuple(2, "3", '4'), 1, f) == hana::make_tuple( |
27 | 1, |
28 | "f(1, 2)", |
29 | "f(f(1, 2), 3)", |
30 | "f(f(f(1, 2), 3), 4)" |
31 | )); |
32 | |
33 | // without initial state |
34 | BOOST_HANA_RUNTIME_CHECK(hana::scan_left(hana::make_tuple(1, "2", '3'), f) == hana::make_tuple( |
35 | 1, |
36 | "f(1, 2)", |
37 | "f(f(1, 2), 3)" |
38 | )); |
39 | } |
40 |