Add mp_for_each

include/boost/mp11/algorithm.hpp

@@ -20,6 +20,7 @@
 #include <boost/config.hpp>
 #include <boost/detail/workaround.hpp>
 #include <type_traits>
+#include <utility>
 
 namespace boost
 {
@@ -823,6 +824,31 @@ template<class L, class I, class W> struct mp_replace_at_impl
 template<class L, class I, class W> using mp_replace_at = typename detail::mp_replace_at_impl<L, I, W>::type;
 template<class L, std::size_t I, class W> using mp_replace_at_c = typename detail::mp_replace_at_impl<L, mp_size_t<I>, W>::type;
 
+namespace detail
+{
+
+template<class... T, class F> BOOST_CONSTEXPR F mp_for_each_impl( mp_list<T...>, F && f )
+{
+    using A = int[sizeof...(T)];
+    return (void)A{ ((void)f(mp_identity<T>()), 0)... }, std::forward<F>(f);
+}
+
+#if BOOST_WORKAROUND( BOOST_MSVC, <= 1800 )
+
+template<class F> BOOST_CONSTEXPR F mp_for_each_impl( mp_list<>, F && f )
+{
+    return std::forward<F>(f);
+}
+
+#endif
+
+} // namespace detail
+
+template<class L, class F> BOOST_CONSTEXPR F mp_for_each( F && f )
+{
+    return detail::mp_for_each_impl( mp_rename<L, mp_list>(), std::forward<F>(f) );
+}
+
 } // namespace mp11
 } // namespace boost
 

test/Jamfile.v2

@@ -64,6 +64,7 @@ run mp_any_of.cpp : : : $(REQ) ;
 run mp_none_of.cpp : : : $(REQ) ;
 run mp_replace_at.cpp : : : $(REQ) ;
 run mp_replace_at_c.cpp : : : $(REQ) ;
+run mp_for_each.cpp : : : $(REQ) ;
 
 # integral
 run integral.cpp : : : $(REQ) ;

test/mp_for_each.cpp

@@ -0,0 +1,72 @@
+
+//  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/list.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/config.hpp>
+#include <boost/detail/workaround.hpp>
+#include <tuple>
+
+using boost::mp11::mp_identity;
+
+#if !defined( BOOST_NO_CXX14_CONSTEXPR )
+# define CONSTEXPR14 constexpr
+#else
+# define CONSTEXPR14
+#endif
+
+struct F
+{
+    int s;
+
+    CONSTEXPR14 void operator()( mp_identity<int> ) { s = s * 10 + 1; }
+    CONSTEXPR14 void operator()( mp_identity<short> ) { s = s * 10 + 2; }
+    CONSTEXPR14 void operator()( mp_identity<char> ) { s = s * 10 + 3; }
+};
+
+using boost::mp11::mp_list;
+using boost::mp11::mp_for_each;
+
+int main()
+{
+    BOOST_TEST_EQ( (mp_for_each<mp_list<>>( 11 )), 11 );
+    BOOST_TEST_EQ( (mp_for_each<mp_list<int>>( F{0} ).s), 1 );
+    BOOST_TEST_EQ( (mp_for_each<mp_list<int, short>>( F{0} ).s), 12 );
+    BOOST_TEST_EQ( (mp_for_each<mp_list<int, short, char>>( F{0} ).s), 123 );
+
+    BOOST_TEST_EQ( (mp_for_each<std::tuple<>>( 11 )), 11 );
+    BOOST_TEST_EQ( (mp_for_each<std::tuple<int>>( F{0} ).s), 1 );
+    BOOST_TEST_EQ( (mp_for_each<std::tuple<int, short>>( F{0} ).s), 12 );
+    BOOST_TEST_EQ( (mp_for_each<std::tuple<int, short, char>>( F{0} ).s), 123 );
+
+    BOOST_TEST_EQ( (mp_for_each<std::pair<int, short>>( F{0} ).s), 12 );
+
+#if !defined( BOOST_NO_CXX11_CONSTEXPR )
+
+    static_assert( mp_for_each<mp_list<>>( 11 ) == 11, "mp_for_each<mp_list<>>( 11 ) == 11" );
+    static_assert( mp_for_each<std::tuple<>>( 12 ) == 12, "mp_for_each<std::tuple<>>( 12 ) == 12" );
+
+#endif
+
+#if !defined( BOOST_NO_CXX14_CONSTEXPR ) && !BOOST_WORKAROUND( BOOST_MSVC, <= 1910 )
+
+    constexpr auto r1 = mp_for_each<mp_list<int, short, char>>( F{0} );
+    static_assert( r1.s == 123, "r1.s == 123" );
+
+    constexpr auto r2 = mp_for_each<std::tuple<int, short, char>>( F{0} );
+    static_assert( r2.s == 123, "r2.s == 123" );
+
+    constexpr auto r3 = mp_for_each<std::pair<int, short>>( F{0} );
+    static_assert( r3.s == 12, "r3.s == 12" );
+
+#endif
+
+    return boost::report_errors();
+}