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

40 lines
1009 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/equal.hpp>
#include <boost/hana/scan_right.hpp>
#include <boost/hana/tuple.hpp>
#include <sstream>
namespace hana = boost::hana;
auto to_string = [](auto x) {
std::ostringstream ss;
ss << x;
return ss.str();
};
auto f = [](auto element, auto state) {
return "f(" + to_string(element) + ", " + to_string(state) + ")";
};
int main() {
// with initial state
BOOST_HANA_RUNTIME_CHECK(hana::scan_right(hana::make_tuple(1, "2", '3'), 4, f) == hana::make_tuple(
"f(1, f(2, f(3, 4)))",
"f(2, f(3, 4))",
"f(3, 4)",
4
));
// without initial state
BOOST_HANA_RUNTIME_CHECK(hana::scan_right(hana::make_tuple(1, "2", '3'), f) == hana::make_tuple(
"f(1, f(2, 3))",
"f(2, 3)",
'3'
));
}