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Implement mp_transform_if in terms of mp_transform

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Peter Dimov
2017-04-01 18:08:19 +03:00
parent fcbe835f4b
commit c92d314009
2 changed files with 22 additions and 55 deletions
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67
include/boost/mp11/algorithm.hpp
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@@ -105,65 +105,22 @@ template<template<class...> class F, template<class...> class L1, class... T1, t
namespace detail
{
/*
template<template<class...> class P, template<class...> class F, class... L> struct mp_transform_if_impl
{
// error: pack expansion used as argument for non-pack parameter of alias template
template<class... U> using _f = mp_eval_if<mp_not<P<U...>>, mp_first<mp_list<U...>>, F, U...>;
// the stupid quote-unquote dance avoids "pack expansion used as argument for non-pack parameter of alias template"
#if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, <= 1910 )
template<class... U> struct _f_ { using type = mp_eval_if<mp_not<mp_invoke<mp_quote<P>, U...>>, mp_first<mp_list<U...>>, mp_quote<F>::template fn, U...>; };
template<class... U> using _f = typename _f_<U...>::type;
#else
template<class... U> using _f = mp_eval_if<mp_not<mp_invoke<mp_quote<P>, U...>>, mp_first<mp_list<U...>>, mp_quote<F>::template fn, U...>;
#endif
using type = mp_transform<_f, L...>;
};
*/
template<template<class...> class P, template<class...> class F, class... L> struct mp_transform_if_impl;
template<template<class...> class P, template<class...> class F, template<class...> class L, class... T> struct mp_transform_if_impl<P, F, L<T...>>
{
#if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, <= 1910 )
template<class U> struct _f { using type = mp_eval_if<mp_not<P<U>>, U, F, U>; };
using type = L<typename _f<T>::type...>;
#else
template<class U> using _f = mp_eval_if<mp_not<P<U>>, U, F, U>;
using type = L<_f<T>...>;
#endif
};
template<template<class...> class P, template<class...> class F, template<class...> class L1, class... T1, template<class...> class L2, class... T2> struct mp_transform_if_impl<P, F, L1<T1...>, L2<T2...>>
{
static_assert( sizeof...(T1) == sizeof...(T2), "The arguments of mp_transform_if should be of the same size" );
#if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, <= 1910 )
template<class U1, class U2> struct _f { using type = mp_eval_if<mp_not<P<U1, U2>>, U1, F, U1, U2>; };
using type = L1<typename _f<T1, T2>::type...>;
#else
template<class U1, class U2> using _f = mp_eval_if<mp_not<P<U1, U2>>, U1, F, U1, U2>;
using type = L1<_f<T1, T2>...>;
#endif
};
template<template<class...> class P, template<class...> class F, template<class...> class L1, class... T1, template<class...> class L2, class... T2, template<class...> class L3, class... T3> struct mp_transform_if_impl<P, F, L1<T1...>, L2<T2...>, L3<T3...>>
{
static_assert( sizeof...(T1) == sizeof...(T2) && sizeof...(T1) == sizeof...(T3), "The arguments of mp_transform_if should be of the same size" );
#if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, <= 1910 )
template<class U1, class U2, class U3> struct _f { using type = mp_eval_if<mp_not<P<U1, U2, U3>>, U1, F, U1, U2, U3>; };
using type = L1<typename _f<T1, T2, T3>::type...>;
#else
template<class U1, class U2, class U3> using _f = mp_eval_if<mp_not<P<U1, U2, U3>>, U1, F, U1, U2, U3>;
using type = L1<_f<T1, T2, T3>...>;
#endif
};
} // namespace detail