proj.cpp
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/*=============================================================================
Copyright (c) 2017 Paul Fultz II
proj.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/proj.hpp>
#include <boost/hof/placeholders.hpp>
#include <boost/hof/mutable.hpp>
#include "test.hpp"
#include <memory>
struct foo
{
constexpr foo(int xp) : x(xp)
{}
int x;
};
struct select_x
{
template<class T>
constexpr auto operator()(T&& x) const BOOST_HOF_RETURNS(x.x);
};
BOOST_HOF_TEST_CASE()
{
#ifndef _MSC_VER
constexpr
#endif
auto add = boost::hof::_ + boost::hof::_;
BOOST_HOF_STATIC_TEST_CHECK(boost::hof::proj(select_x(), add)(foo(1), foo(2)) == 3);
// Using mutable_ as a workaround on libc++, since mem_fn does not meet the
// requirements of a FunctionObject
BOOST_HOF_TEST_CHECK(boost::hof::proj(boost::hof::mutable_(std::mem_fn(&foo::x)), add)(foo(1), foo(2)) == 3);
static_assert(boost::hof::detail::is_default_constructible<decltype(boost::hof::proj(select_x(), add))>::value, "Not default constructible");
}
BOOST_HOF_TEST_CASE()
{
#ifndef _MSC_VER
constexpr
#endif
auto add = boost::hof::_ + boost::hof::_;
BOOST_HOF_STATIC_TEST_CHECK(boost::hof::proj(select_x(), add)(foo(1), foo(2)) == 3);
BOOST_HOF_TEST_CHECK(boost::hof::proj(&foo::x, add)(foo(1), foo(2)) == 3);
static_assert(boost::hof::detail::is_default_constructible<decltype(boost::hof::proj(select_x(), add))>::value, "Not default constructible");
}
BOOST_HOF_TEST_CASE()
{
auto indirect_add = boost::hof::proj(*boost::hof::_, boost::hof::_ + boost::hof::_);
BOOST_HOF_TEST_CHECK(indirect_add(std::unique_ptr<int>(new int(1)), std::unique_ptr<int>(new int(2))) == 3);
static_assert(boost::hof::detail::is_default_constructible<decltype(indirect_add)>::value, "Not default constructible");
}
struct select_x_1
{
std::unique_ptr<int> i;
select_x_1() : i(new int(2))
{}
template<class T>
auto operator()(T&& x) const BOOST_HOF_RETURNS(x.x * (*i));
};
struct sum_1
{
std::unique_ptr<int> i;
sum_1() : i(new int(1))
{}
template<class T, class U>
auto operator()(T&& x, U&& y) const BOOST_HOF_RETURNS(x + y + *i);
};
BOOST_HOF_TEST_CASE()
{
BOOST_HOF_TEST_CHECK(boost::hof::proj(select_x_1(), sum_1())(foo(1), foo(2)) == 7);
}
BOOST_HOF_TEST_CASE()
{
std::string s;
auto f = [&](const std::string& x)
{
s += x;
};
boost::hof::proj(f)("hello", "-", "world");
BOOST_HOF_TEST_CHECK(s == "hello-world");
boost::hof::proj(f)();
BOOST_HOF_TEST_CHECK(s == "hello-world");
}
BOOST_HOF_TEST_CASE()
{
std::string s;
auto f = [&](const std::string& x)
{
s += x;
return s;
};
auto last = [](const std::string& x, const std::string& y, const std::string& z)
{
BOOST_HOF_TEST_CHECK(x == "hello");
BOOST_HOF_TEST_CHECK(y == "hello-");
BOOST_HOF_TEST_CHECK(z == "hello-world");
return z;
};
BOOST_HOF_TEST_CHECK(boost::hof::proj(f, last)("hello", "-", "world") == "hello-world");
}
template<bool B>
struct bool_
{
static const bool value = B;
};
struct constexpr_check
{
template<class T>
constexpr int operator()(T) const
{
static_assert(T::value, "Failed");
return 0;
}
};
struct constexpr_check_each
{
template<class T>
constexpr bool operator()(T x) const
{
return boost::hof::proj(constexpr_check())(x, x), true;
}
};
BOOST_HOF_TEST_CASE()
{
BOOST_HOF_STATIC_TEST_CHECK(constexpr_check_each()(bool_<true>()));
}
BOOST_HOF_TEST_CASE()
{
boost::hof::proj(boost::hof::identity, boost::hof::identity)(0);
}
struct bar {};
BOOST_HOF_TEST_CASE()
{
auto f = boost::hof::proj(bar{});
static_assert(!boost::hof::is_invocable<decltype(f), int>::value, "Not sfinae friendly");
static_assert(!boost::hof::is_invocable<decltype(f), int, int>::value, "Not sfinae friendly");
static_assert(!boost::hof::is_invocable<decltype(f), int, int, int>::value, "Not sfinae friendly");
}
BOOST_HOF_TEST_CASE()
{
auto f = boost::hof::proj(bar{}, bar{});
static_assert(!boost::hof::is_invocable<decltype(f), int>::value, "Not sfinae friendly");
static_assert(!boost::hof::is_invocable<decltype(f), int, int>::value, "Not sfinae friendly");
static_assert(!boost::hof::is_invocable<decltype(f), int, int, int>::value, "Not sfinae friendly");
static_assert(!boost::hof::is_invocable<decltype(f)>::value, "Not sfinae friendly");
}