fold.cpp
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/*=============================================================================
Copyright (c) 2017 Paul Fultz II
fold.cpp
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
==============================================================================*/
#include <boost/hof/fold.hpp>
#include "test.hpp"
struct max_f
{
template<class T, class U>
constexpr T operator()(T x, U y) const noexcept
{
return x > y ? x : y;
}
};
struct sum_f
{
template<class T, class U>
constexpr T operator()(T x, U y) const BOOST_HOF_RETURNS_DEDUCE_NOEXCEPT(x+y)
{
return x + y;
}
};
#if BOOST_HOF_HAS_NOEXCEPT_DEDUCTION
BOOST_HOF_TEST_CASE()
{
static_assert(noexcept(boost::hof::fold(max_f(), 0)(2, 3, 4, 5)), "noexcept fold");
static_assert(noexcept(boost::hof::fold(sum_f(), 0)(2, 3, 4, 5)), "noexcept fold");
static_assert(!noexcept(boost::hof::fold(sum_f(), std::string())("hello", "-", "world")), "noexcept fold");
}
#endif
BOOST_HOF_TEST_CASE()
{
BOOST_HOF_TEST_CHECK(boost::hof::fold(max_f(), 0)(2, 3, 4, 5) == 5);
BOOST_HOF_TEST_CHECK(boost::hof::fold(max_f(), 0)(5, 4, 3, 2) == 5);
BOOST_HOF_TEST_CHECK(boost::hof::fold(max_f(), 0)(2, 3, 5, 4) == 5);
BOOST_HOF_STATIC_TEST_CHECK(boost::hof::fold(max_f(), 0)(2, 3, 4, 5) == 5);
BOOST_HOF_STATIC_TEST_CHECK(boost::hof::fold(max_f(), 0)(5, 4, 3, 2) == 5);
BOOST_HOF_STATIC_TEST_CHECK(boost::hof::fold(max_f(), 0)(2, 3, 5, 4) == 5);
}
BOOST_HOF_TEST_CASE()
{
BOOST_HOF_TEST_CHECK(boost::hof::fold(max_f(), 0)() == 0);
BOOST_HOF_TEST_CHECK(boost::hof::fold(max_f(), 0)(5) == 5);
BOOST_HOF_STATIC_TEST_CHECK(boost::hof::fold(max_f(), 0)() == 0);
BOOST_HOF_STATIC_TEST_CHECK(boost::hof::fold(max_f(), 0)(5) == 5);
}
template<class... Ts>
constexpr auto find_positive_max(Ts... xs) BOOST_HOF_RETURNS
(
boost::hof::fold(max_f(), 0)(xs...)
);
BOOST_HOF_TEST_CASE()
{
BOOST_HOF_TEST_CHECK(find_positive_max() == 0);
BOOST_HOF_TEST_CHECK(find_positive_max(5) == 5);
BOOST_HOF_STATIC_TEST_CHECK(find_positive_max() == 0);
BOOST_HOF_STATIC_TEST_CHECK(find_positive_max(5) == 5);
}
BOOST_HOF_TEST_CASE()
{
BOOST_HOF_TEST_CHECK(boost::hof::fold(max_f())(5) == 5);
BOOST_HOF_STATIC_TEST_CHECK(boost::hof::fold(max_f())(5) == 5);
}
BOOST_HOF_TEST_CASE()
{
BOOST_HOF_TEST_CHECK(boost::hof::fold(max_f())(2, 3, 4, 5) == 5);
BOOST_HOF_TEST_CHECK(boost::hof::fold(max_f())(5, 4, 3, 2) == 5);
BOOST_HOF_TEST_CHECK(boost::hof::fold(max_f())(2, 3, 5, 4) == 5);
BOOST_HOF_STATIC_TEST_CHECK(boost::hof::fold(max_f())(2, 3, 4, 5) == 5);
BOOST_HOF_STATIC_TEST_CHECK(boost::hof::fold(max_f())(5, 4, 3, 2) == 5);
BOOST_HOF_STATIC_TEST_CHECK(boost::hof::fold(max_f())(2, 3, 5, 4) == 5);
}
BOOST_HOF_TEST_CASE()
{
BOOST_HOF_TEST_CHECK(boost::hof::fold(sum_f(), std::string())("hello", "-", "world") == "hello-world");
}