Add mp_list_c, mp_from_sequence

doc/mp11/algorithm.adoc

@@ -297,6 +297,17 @@ As `mp_product`, but takes a quoted metafunction.
 
 Same as `mp_drop_c`, but with a type argument `N`. `N::value` must be a nonnegative number.
 
+## mp_from_sequence<S>
+
+    template<class S> using mp_from_sequence = /*...*/
+
+`mp_from_sequence` transforms an integer sequence produced by `make_integer_sequence` into an `mp_list`
+of the corresponding `std::integral_constant` types. Given
+
+    template<class T, class... I> struct S;
+
+`mp_from_sequence<S<T, I...>>` is an alias for `mp_list<std::integral_constant<T, I>...>`.
+
 ## mp_iota_c<N>
 
     template<std::size_t N> using mp_iota_c = /*...*/;

doc/mp11/list.adoc

@@ -21,6 +21,18 @@ http://www.boost.org/LICENSE_1_0.txt
 such as `std::tuple` or `std::variant`. Even `std::pair` can be used if the transformation does not alter the number of the elements in
 the list.
 
+## mp_list_c<T, I...>
+
+    template<class T, T... I> using mp_list_c =
+        mp_list<std::integral_constant<T, I>...>;
+
+`mp_list_c` produces an `mp_list` of the `std::integral_constant` types corresponding to its integer template arguments.
+
+.Using mp_list_c
+```
+using L1 = mp_list_c<int, 2, 3>; // mp_list<mp_int<2>, mp_int<3>>
+```
+
 ## mp_is_list<L>
 
     template<class L> using mp_is_list = /*...*/;

include/boost/mp11/algorithm.hpp

@@ -287,7 +287,7 @@ template<class L, std::size_t N> using mp_drop_c = typename detail::mp_drop_impl
 
 template<class L, class N> using mp_drop = typename detail::mp_drop_impl<L, mp_repeat<mp_list<void>, N>>::type;
 
-// mp_iota(_c)<N>
+// mp_from_sequence<S>
 namespace detail
 {
 
@@ -298,12 +298,13 @@ template<template<class T, T... I> class S, class U, U... J> struct mp_from_sequ
     using type = mp_list<std::integral_constant<U, J>...>;
 };
 
-template<class S> using mp_from_sequence = typename mp_from_sequence_impl<S>::type;
-
 } // namespace detail
 
-template<std::size_t N> using mp_iota_c = detail::mp_from_sequence<make_index_sequence<N>>;
-template<class N> using mp_iota = detail::mp_from_sequence<make_integer_sequence<typename std::remove_const<decltype(N::value)>::type, N::value>>;
+template<class S> using mp_from_sequence = typename detail::mp_from_sequence_impl<S>::type;
+
+// mp_iota(_c)<N>
+template<std::size_t N> using mp_iota_c = mp_from_sequence<make_index_sequence<N>>;
+template<class N> using mp_iota = mp_from_sequence<make_integer_sequence<typename std::remove_const<decltype(N::value)>::type, N::value>>;
 
 // mp_at(_c)<L, I>
 namespace detail

include/boost/mp11/list.hpp

@@ -13,12 +13,16 @@
 #include <boost/mp11/detail/mp_append.hpp>
 #include <boost/config.hpp>
 #include <boost/detail/workaround.hpp>
+#include <type_traits>
 
 namespace boost
 {
 namespace mp11
 {
 
+// mp_list_c<T, I...>
+template<class T, T... I> using mp_list_c = mp_list<std::integral_constant<T, I>...>;
+
 // mp_is_list<L>
 namespace detail
 {

test/Jamfile

@@ -31,6 +31,7 @@ run mp_replace_second.cpp ;
 run mp_replace_third.cpp ;
 run mp_apply_q.cpp ;
 run mp_is_list.cpp ;
+run mp_list_c.cpp ;
 
 # algorithm
 run mp_assign.cpp ;
@@ -74,6 +75,7 @@ run mp_insert.cpp ;
 run mp_erase.cpp ;
 run mp_with_index.cpp ;
 run mp_with_index_cx.cpp ;
+run mp_from_sequence.cpp ;
 
 # integral
 run integral.cpp ;

test/mp_from_sequence.cpp

@@ -0,0 +1,43 @@
+
+// Copyright 2017 Peter Dimov.
+//
+// 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/mp11/algorithm.hpp>
+#include <boost/mp11/integral.hpp>
+#include <boost/mp11/integer_sequence.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+
+template<class T, T... I> struct S;
+
+int main()
+{
+    using boost::mp11::mp_list;
+    using boost::mp11::mp_from_sequence;
+    using boost::mp11::mp_int;
+    using boost::mp11::mp_size_t;
+    using boost::mp11::make_integer_sequence;
+    using boost::mp11::make_index_sequence;
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<S<int>>, mp_list<>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<S<int, 1>>, mp_list<mp_int<1>>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<S<int, 1, 3>>, mp_list<mp_int<1>, mp_int<3>>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<S<int, 1, 3, 5>>, mp_list<mp_int<1>, mp_int<3>, mp_int<5>>>));
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<make_integer_sequence<int, 0>>, mp_list<>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<make_integer_sequence<int, 1>>, mp_list<mp_int<0>>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<make_integer_sequence<int, 2>>, mp_list<mp_int<0>, mp_int<1>>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<make_integer_sequence<int, 3>>, mp_list<mp_int<0>, mp_int<1>, mp_int<2>>>));
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<make_index_sequence<0>>, mp_list<>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<make_index_sequence<1>>, mp_list<mp_size_t<0>>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<make_index_sequence<2>>, mp_list<mp_size_t<0>, mp_size_t<1>>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_from_sequence<make_index_sequence<3>>, mp_list<mp_size_t<0>, mp_size_t<1>, mp_size_t<2>>>));
+
+    return boost::report_errors();
+}

test/mp_list_c.cpp

@@ -0,0 +1,27 @@
+
+// Copyright 2017 Peter Dimov.
+//
+// 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/mp11/list.hpp>
+#include <boost/mp11/integral.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+
+int main()
+{
+    using boost::mp11::mp_list_c;
+    using boost::mp11::mp_list;
+    using boost::mp11::mp_int;
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_list_c<int>, mp_list<>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_list_c<int, 1>, mp_list<mp_int<1>>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_list_c<int, 1, 3>, mp_list<mp_int<1>, mp_int<3>>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_list_c<int, 1, 3, 5>, mp_list<mp_int<1>, mp_int<3>, mp_int<5>>>));
+
+    return boost::report_errors();
+}