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Unroll mp_fold.

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Peter Dimov
2017-03-24 17:21:38 +02:00
parent 2bf9bad934
commit e488469e9a
2 changed files with 26 additions and 0 deletions
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5
include/boost/mp11/algorithm.hpp
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@@ -758,6 +758,11 @@ template<template<class...> class L, class T1, class... T, class V, template<cla
using type = typename mp_fold_impl<L<T...>, F<V, T1>, F>::type;
};
template<template<class...> class L, class T1, class T2, class T3, class T4, class T5, class T6, class T7, class T8, class T9, class T10, class... T, class V, template<class...> class F> struct mp_fold_impl<L<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T...>, V, F>
{
using type = typename mp_fold_impl<L<T...>, F<F<F<F<F<F<F<F<F<F<V, T1>, T2>, T3>, T4>, T5>, T6>, T7>, T8>, T9>, T10>, F>::type;
};
} // namespace detail
template<class L, class V, template<class...> class F> using mp_fold = typename detail::mp_fold_impl<L, V, F>::type;

21
test/mp_fold.cpp
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@@ -9,6 +9,7 @@
#include <boost/mp11/algorithm.hpp>
#include <boost/mp11/list.hpp>
#include <boost/mp11/integral.hpp>
#include <boost/core/lightweight_test_trait.hpp>
#include <type_traits>
#include <tuple>
@@ -53,5 +54,25 @@ int main()
BOOST_TEST_TRAIT_TRUE((std::is_same<mp_fold<std::tuple<X1, X2, X3, X4>, mp_list<>, mp_push_front>, mp_list<X4, X3, X2, X1>>));
}
using boost::mp11::mp_iota_c;
using boost::mp11::mp_reverse;
using boost::mp11::mp_size_t;
using boost::mp11::mp_plus;
{
int const N = 37;
using L = mp_iota_c<N>;
using R1 = mp_fold<L, mp_list<>, mp_push_back>;
BOOST_TEST_TRAIT_TRUE((std::is_same<R1, L>));
using R2 = mp_fold<L, mp_list<>, mp_push_front>;
BOOST_TEST_TRAIT_TRUE((std::is_same<R2, mp_reverse<L>>));
using R3 = mp_fold<L, mp_size_t<0>, mp_plus>;
BOOST_TEST_TRAIT_TRUE((std::is_same<R3, mp_size_t<N*(N-1)/2>>));
}
return boost::report_errors();
}