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// Copyright 2023 Jody Hagins
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#include <boost/mp11.hpp>
using namespace boost::mp11;
// A simple metafunction that takes the first three items from a list
template <typename T>
using take3 = mp_take<T, mp_int<3>>;
// Directly call take3
static_assert(mp_same<
take3<mp_iota_c<9>>,
mp_list<mp_size_t<0>, mp_size_t<1>, mp_size_t<2>>>::value, "");
// Invoke a quoted take3 (mp_quote<take3>)
static_assert(mp_same<
mp_invoke_q<mp_quote<take3>, mp_iota_c<9>>,
mp_list<mp_size_t<0>, mp_size_t<1>, mp_size_t<2>>>::value, "");
#if !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1900 )
// Invoke a composed take3 (mp_compose<take3>)
static_assert(mp_same<
mp_invoke_q<mp_compose<take3>, mp_iota_c<9>>,
mp_list<mp_size_t<0>, mp_size_t<1>, mp_size_t<2>>>::value, "");
#endif
// If we apply the following iteration, we expect to get all triplets of the list.
using expected = mp_list<
mp_list<mp_size_t<0>, mp_size_t<1>, mp_size_t<2>>,
mp_list<mp_size_t<3>, mp_size_t<4>, mp_size_t<5>>,
mp_list<mp_size_t<6>, mp_size_t<7>, mp_size_t<8>>>;
// First using mp_quote - this works as expected
static_assert(
mp_same<
mp_iterate_q<
mp_iota_c<9>,
mp_quote<take3>,
mp_bind_back<mp_drop, mp_int<3>>>,
expected>::value, "");
#if !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1900 )
// Next, simply replace mp_quote with mp_compose. We expect to get the same answer,
// but we get a hard compiler error instead.
static_assert(
mp_same<
mp_iterate_q<
mp_iota_c<9>,
mp_compose<take3>,
mp_bind_back<mp_drop, mp_int<3>>>,
expected>::value, "");
#endif
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