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hana/example/iterable.cpp
2015-06-08 14:49:26 -04:00

154 lines
3.7 KiB
C++

/*
@copyright Louis Dionne 2015
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/config.hpp>
#include <boost/hana/ext/std/integral_constant.hpp>
#include <boost/hana/integral_constant.hpp>
#include <boost/hana/optional.hpp>
#include <boost/hana/range.hpp>
#include <boost/hana/tuple.hpp>
#include <boost/hana/type.hpp>
#include <sstream>
#include <type_traits>
using namespace boost::hana;
int main() {
//////////////////////////////////////////////////////////////////////////////
// Models
//////////////////////////////////////////////////////////////////////////////
{
//! [Searchable]
BOOST_HANA_CONSTEXPR_CHECK(
find_if(make<Tuple>(1.0, 2, '3'), trait<std::is_integral>) == just(2)
);
BOOST_HANA_CONSTANT_CHECK(
find_if(make<Tuple>(1.0, 2, '3'), trait<std::is_class>) == nothing
);
BOOST_HANA_CONSTANT_CHECK(
find(make<Tuple>(int_<1>, char_<'c'>, type<void>), type<void>) == just(type<void>)
);
BOOST_HANA_CONSTANT_CHECK(
find(make<Tuple>(int_<1>, char_<'c'>, type<void>), type<int>) == nothing
);
//! [Searchable]
}
//////////////////////////////////////////////////////////////////////////////
// Methods
//////////////////////////////////////////////////////////////////////////////
{
//! [at]
BOOST_HANA_CONSTEXPR_CHECK(at(make_tuple(0, '1', 2.0), int_<0>) == 0);
BOOST_HANA_CONSTEXPR_CHECK(at(make_tuple(0, '1', 2.0), int_<1>) == '1');
BOOST_HANA_CONSTEXPR_CHECK(at(make_tuple(0, '1', 2.0), int_<2>) == 2.0);
//! [at]
}{
//! [at_c]
BOOST_HANA_CONSTEXPR_CHECK(at_c<0>(make_tuple(0, '1', 2.0)) == 0);
BOOST_HANA_CONSTEXPR_CHECK(at_c<1>(make_tuple(0, '1', 2.0)) == '1');
BOOST_HANA_CONSTEXPR_CHECK(at_c<2>(make_tuple(0, '1', 2.0)) == 2.0);
//! [at_c]
}{
//! [drop]
constexpr auto xs = make_tuple(0, '1', 2.0);
// drop (equivalent to drop.at_most)
static_assert(drop(xs, int_<0>) == xs, "");
static_assert(drop(xs, int_<1>) == make_tuple('1', 2.0), "");
static_assert(drop(xs, int_<2>) == make_tuple(2.0), "");
BOOST_HANA_CONSTANT_CHECK(drop(xs, int_<3>) == make_tuple());
BOOST_HANA_CONSTANT_CHECK(drop(xs, int_<4>) == make_tuple());
BOOST_HANA_CONSTANT_CHECK(drop.at_most(xs, int_<4>) == make_tuple());
// drop.exactly
static_assert(drop.exactly(xs, int_<2>) == make_tuple(2.0), "");
BOOST_HANA_CONSTANT_CHECK(drop.exactly(xs, int_<3>) == make_tuple());
//! [drop]
}{
//! [drop_c]
static_assert(drop_c<2>(make_tuple(0, '1', 2.0)) == make_tuple(2.0), "");
//! [drop_c]
}{
//! [drop_until]
using namespace boost::hana::literals;
BOOST_HANA_CONSTEXPR_LAMBDA auto positive = [](auto x) {
return x > int_<0>;
};
BOOST_HANA_CONSTANT_CHECK(
drop_until(range(int_<-3>, int_<6>), positive) == range(int_<1>, int_<6>)
);
BOOST_HANA_CONSTANT_CHECK(
drop_until(make<Tuple>(1_c, -2_c, 4_c, 5_c), positive) == make<Tuple>(1_c, -2_c, 4_c, 5_c)
);
//! [drop_until]
}{
//! [drop_while]
using namespace literals;
BOOST_HANA_CONSTEXPR_LAMBDA auto negative = [](auto x) {
return x < int_<0>;
};
BOOST_HANA_CONSTANT_CHECK(
drop_while(range(int_<-3>, int_<6>), negative) == range(int_<0>, int_<6>)
);
BOOST_HANA_CONSTANT_CHECK(
drop_while(make<Tuple>(1_c, -2_c, 4_c, 5_c), negative) == make<Tuple>(1_c, -2_c, 4_c, 5_c)
);
//! [drop_while]
}{
//! [head]
BOOST_HANA_CONSTEXPR_CHECK(head(make<Tuple>(1, '2', 3.3, nullptr)) == 1);
//! [head]
}{
//! [is_empty]
BOOST_HANA_CONSTANT_CHECK(!is_empty(make<Tuple>(1, '2')));
BOOST_HANA_CONSTANT_CHECK( is_empty(make<Tuple>()));
//! [is_empty]
}{
//! [last]
BOOST_HANA_CONSTEXPR_CHECK(last(make<Tuple>(1, '2', 3.3, nullptr)) == nullptr);
//! [last]
}{
//! [tail]
BOOST_HANA_CONSTEXPR_CHECK(
tail(make<Tuple>(1, '2', 3.3, nullptr)) == make<Tuple>('2', 3.3, nullptr)
);
//! [tail]
}
}