diff --git a/doc/html/mp11.html b/doc/html/mp11.html
index db32cd8..b1cc0c6 100644
--- a/doc/html/mp11.html
+++ b/doc/html/mp11.html
@@ -179,8 +179,9 @@
Mp11 is a C++11 metaprogramming library based on template aliases and variadic
templates. It implements the approach outlined in the article Simple
- C++11 metaprogramming (part
- 2).
+ C++11 metaprogramming and its
+ sequel. Reading these articles before proceeding with this documentation
+ is highly recommended.
The general principles upon which Mp11 is built are that algorithms and metafunctions
@@ -322,7 +323,8 @@
using T3 = decltype( T1() + T2() );
using T4 = result<T1, T2>;
- std::cout << ( std::is_same<T3, T4>::value? "[PASS] ": "[FAIL] " ) << name<T1>() << " + " << name<T2>() << " -> " << name<T3>() << ", result: " << name<T4>() << " " << std::endl;
+ std::cout << ( std::is_same<T3, T4>::value? "[PASS] ": "[FAIL] " )
+ << name<T1>() << " + " << name<T2>() << " -> " << name<T3>() << ", result: " << name<T4>() << std::endl;
}
int main()
@@ -707,7 +709,7 @@
template<template<class...> class F, class L> using mp_apply = mp_rename<L, F>;
- mp_apply<F, L> applies the function F to the contents of the list L, that is, mp_rename<F, L<T...>>
+ mp_apply<F, L> applies the metafunction F to the contents of the list L, that is, mp_rename<F, L<T...>>
is an alias for F<T...>.
(mp_apply is the same as
mp_rename with the arguments
@@ -973,9 +975,8 @@
mp_transform_if<P, F, L1, L2, ..., Ln>
- replaces the elements T
- of the list L1 for which
- mp_to_bool<P<T1, T2, ..., Tn>> is mp_true
+ replaces the elements of the list L1
+ for which mp_to_bool<P<T1, T2, ..., Tn>> is mp_true
with F<T1, T2, ..., Tn>, and returns the result, where Ti are the corresponding elements of
Li.
@@ -1310,7 +1311,7 @@
is the zero-based index of the first element T
in L for which mp_to_bool<P<T>>
is mp_true. If there is
- no such element, mp_find<L, V>
+ no such element, mp_find_if<L, P>
is mp_size<L>.
@@ -1477,7 +1478,7 @@
template<class M, class K> using mp_map_contains = mp_not<std::is_same<mp_map_find<M, K>, void>>;
- mp_map_contains<M, K> is mp_true,
+ mp_map_contains<M, K> is mp_true
if the map M contains an
element with a key K,
mp_false otherwise.
@@ -1705,7 +1706,7 @@
-Last revised: March 24, 2017 at 12:24:11 GMT |
+Last revised: March 25, 2017 at 01:01:08 GMT |
|
diff --git a/doc/mp11/algorithm.qbk b/doc/mp11/algorithm.qbk
index f03b5c4..e4a3991 100644
--- a/doc/mp11/algorithm.qbk
+++ b/doc/mp11/algorithm.qbk
@@ -29,7 +29,7 @@
[section `mp_transform_if`]
template class P, template class F, class L...> using mp_transform_if = /*...*/;
-`mp_transform_if` replaces the elements `T` of the list `L1` for which `mp_to_bool>` is `mp_true` with
+`mp_transform_if` replaces the elements of the list `L1` for which `mp_to_bool>` is `mp_true` with
`F`, and returns the result, where `Ti` are the corresponding elements of `Li`.
[endsect]
@@ -193,7 +193,7 @@ for the elements of `L` and `mp_false` for the elements of `L`. Re
template class P> using mp_find_if = /*...*/;
`mp_find_f` is an alias for `mp_size_t`, where `I` is the zero-based index of the first element `T` in `L` for which
-`mp_to_bool>` is `mp_true`. If there is no such element, `mp_find` is `mp_size`.
+`mp_to_bool>` is `mp_true`. If there is no such element, `mp_find_if` is `mp_size`.
[endsect]
[section `mp_reverse`]
diff --git a/doc/mp11/examples.qbk b/doc/mp11/examples.qbk
index ce93678..2644118 100644
--- a/doc/mp11/examples.qbk
+++ b/doc/mp11/examples.qbk
@@ -63,7 +63,8 @@ how we can leverage Mp11 to automate the task:
using T3 = decltype( T1() + T2() );
using T4 = result;
- std::cout << ( std::is_same::value? "[PASS] ": "[FAIL] " ) << name() << " + " << name() << " -> " << name() << ", result: " << name() << " " << std::endl;
+ std::cout << ( std::is_same::value? "[PASS] ": "[FAIL] " )
+ << name() << " + " << name() << " -> " << name() << ", result: " << name() << std::endl;
}
int main()
diff --git a/doc/mp11/list.qbk b/doc/mp11/list.qbk
index 5b01b3b..4c4dcd0 100644
--- a/doc/mp11/list.qbk
+++ b/doc/mp11/list.qbk
@@ -88,7 +88,7 @@ is an alias for `L`.
[section `mp_apply`]
template class F, class L> using mp_apply = mp_rename;
-`mp_apply` applies the function `F` to the contents of the list `L`, that is, `mp_rename>` is an alias for `F`.
+`mp_apply` applies the metafunction `F` to the contents of the list `L`, that is, `mp_rename>` is an alias for `F`.
(`mp_apply` is the same as `mp_rename` with the arguments reversed.)
[endsect]
diff --git a/doc/mp11/map.qbk b/doc/mp11/map.qbk
index f7c1fdb..d76338b 100644
--- a/doc/mp11/map.qbk
+++ b/doc/mp11/map.qbk
@@ -19,7 +19,7 @@ A map is a list of lists, the inner lists having at least one element (the key.)
[section `mp_map_contains`]
template using mp_map_contains = mp_not, void>>;
-`mp_map_contains` is `mp_true`, if the map `M` contains an element with a key `K`, `mp_false` otherwise.
+`mp_map_contains` is `mp_true` if the map `M` contains an element with a key `K`, `mp_false` otherwise.
[endsect]
[section `mp_map_insert`]
diff --git a/doc/mp11/overview.qbk b/doc/mp11/overview.qbk
index 9c1389d..79502b4 100644
--- a/doc/mp11/overview.qbk
+++ b/doc/mp11/overview.qbk
@@ -10,8 +10,9 @@
Mp11 is a C++11 metaprogramming library based on template aliases and variadic templates.
It implements the approach outlined in the article
-[@http://pdimov.com/cpp2/simple_cxx11_metaprogramming.html Simple C++11 metaprogramming]
-([@http://pdimov.com/cpp2/simple_cxx11_metaprogramming_2.html part 2]).
+[@http://pdimov.com/cpp2/simple_cxx11_metaprogramming.html Simple C++11 metaprogramming] and
+[@http://pdimov.com/cpp2/simple_cxx11_metaprogramming_2.html its sequel]. Reading these
+articles before proceeding with this documentation is highly recommended.
The general principles upon which Mp11 is built are that algorithms and metafunctions are
template aliases of the form `F` and data structures are lists of the form `L`,
diff --git a/include/boost/mp11/algorithm.hpp b/include/boost/mp11/algorithm.hpp
index 309255c..cda0eb7 100644
--- a/include/boost/mp11/algorithm.hpp
+++ b/include/boost/mp11/algorithm.hpp
@@ -264,20 +264,29 @@ template using mp_iota = detail::mp_from_sequence struct mp_at_impl
+template struct mp_at_c_impl;
+
+#if defined(BOOST_MP11_HAS_TYPE_PACK_ELEMENT)
+
+template class L, class... T, std::size_t I> struct mp_at_c_impl, I>
{
- static_assert( I::value >= 0, "mp_at: I must not be negative" );
-
- using _map = mp_transform>, L>;
-
- using type = mp_second>>;
+ using type = __type_pack_element;
};
+#else
+
+template struct mp_at_c_impl
+{
+ using _map = mp_transform>, L>;
+ using type = mp_second>>;
+};
+
+#endif
+
} // namespace detail
-template using mp_at_c = typename detail::mp_at_impl>::type;
-
-template using mp_at = typename detail::mp_at_impl::type;
+template using mp_at_c = typename detail::mp_at_c_impl::type;
+template using mp_at = typename detail::mp_at_c_impl::type;
// mp_take(_c)
namespace detail
diff --git a/include/boost/mp11/detail/config.hpp b/include/boost/mp11/detail/config.hpp
index 3992cdc..75c5caa 100644
--- a/include/boost/mp11/detail/config.hpp
+++ b/include/boost/mp11/detail/config.hpp
@@ -29,4 +29,12 @@
# endif
#endif
+#if defined(__has_builtin)
+# if __has_builtin(__type_pack_element)
+
+# define BOOST_MP11_HAS_TYPE_PACK_ELEMENT
+
+# endif
+#endif
+
#endif // #ifndef BOOST_MP11_DETAIL_CONFIG_HPP_INCLUDED