hana/example/transform.cpp
Louis Dionne c334974abe [type] Make metafunction & friends SFINAE friendly
Also add a section to the tutorial showing how to use this functionality.
2018-06-19 21:07:14 -07:00

41 lines
1.2 KiB
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/optional.hpp>
#include <boost/hana/transform.hpp>
#include <boost/hana/tuple.hpp>
#include <boost/hana/type.hpp>
#include <sstream>
#include <string>
#include <type_traits>
namespace hana = boost::hana;
using namespace std::literals;
auto to_string = [](auto x) {
std::ostringstream ss;
ss << x;
return ss.str();
};
int main() {
BOOST_HANA_RUNTIME_CHECK(
hana::transform(hana::make_tuple(1, '2', "345", std::string{"67"}), to_string)
==
hana::make_tuple("1", "2", "345", "67")
);
BOOST_HANA_CONSTANT_CHECK(hana::transform(hana::nothing, to_string) == hana::nothing);
BOOST_HANA_RUNTIME_CHECK(hana::transform(hana::just(123), to_string) == hana::just("123"s));
BOOST_HANA_CONSTANT_CHECK(
hana::transform(hana::tuple_t<void, int(), char[10]>, hana::metafunction<std::add_pointer>)
==
hana::tuple_t<void*, int(*)(), char(*)[10]>
);
}