From 08444e45870b1cb6907b97b7d13fa638c25a1b30 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Mon, 7 Jan 2019 06:50:51 +0200
Subject: [PATCH] Add mp_set_union

---
 doc/mp11/set.adoc          | 11 ++++++--
 include/boost/mp11/set.hpp | 42 ++++++++++++++++++++++++++---
 test/Jamfile               |  2 ++
 test/mp_set_push_back.cpp  |  2 +-
 test/mp_set_union.cpp      | 55 ++++++++++++++++++++++++++++++++++++++
 test/mp_set_union_sf.cpp   | 32 ++++++++++++++++++++++
 6 files changed, 137 insertions(+), 7 deletions(-)
 create mode 100644 test/mp_set_union.cpp
 create mode 100644 test/mp_set_union_sf.cpp

diff --git a/doc/mp11/set.adoc b/doc/mp11/set.adoc
index d57ec73..65b36ce 100644
--- a/doc/mp11/set.adoc
+++ b/doc/mp11/set.adoc
@@ -31,10 +31,17 @@ A set is a list whose elements are unique.
 
     template<class S, class... T> using mp_set_push_back = /*...*/;
 
-For each `T1` in `T...`, `mp_set_push_back<S, T...>` appends `T1` to the end of `S` if it's not already an element of `S`.
+For each `T1` in `T...`, `mp_set_push_back<S, T...>` appends `T1` to the end of the set `S` if it's not already an element of `S`.
 
 ## mp_set_push_front<S, T...>
 
     template<class S, class... T> using mp_set_push_front = /*...*/;
 
-`mp_set_push_front<S, T...>` inserts at the front of `S` those elements of `T...` for which `S` does not already contain the same type.
+`mp_set_push_front<S, T...>` inserts at the front of the set `S` those elements of `T...` for which `S` does not already contain the same type.
+
+## mp_set_union<L...>
+
+    template<class... L> using mp_set_union = /*...*/;
+
+`mp_set_union<S, L...>` is `mp_set_push_back<S, T...>`, where `T...` are the elements of `mp_append<mp_list<>, L...>`.
+`mp_set_union<>` is `mp_list<>`.
diff --git a/include/boost/mp11/set.hpp b/include/boost/mp11/set.hpp
index fe9c1b2..413af7a 100644
--- a/include/boost/mp11/set.hpp
+++ b/include/boost/mp11/set.hpp
@@ -1,15 +1,16 @@
 #ifndef BOOST_MP11_SET_HPP_INCLUDED
 #define BOOST_MP11_SET_HPP_INCLUDED
 
-//  Copyright 2015 Peter Dimov.
+// Copyright 2015, 2019 Peter Dimov.
 //
-//  Distributed under the Boost Software License, Version 1.0.
+// 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
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/mp11/utility.hpp>
 #include <boost/mp11/detail/mp_list.hpp>
+#include <boost/mp11/detail/mp_append.hpp>
 #include <type_traits>
 
 namespace boost
@@ -97,6 +98,39 @@ template<template<class...> class L, class... T> struct mp_is_set_impl<L<T...>>
 
 template<class S> using mp_is_set = typename detail::mp_is_set_impl<S>::type;
 
+// mp_set_union<L...>
+namespace detail
+{
+
+template<class... L> struct mp_set_union_impl
+{
+};
+
+template<> struct mp_set_union_impl<>
+{
+    using type = mp_list<>;
+};
+
+template<template<class...> class L, class... T> struct mp_set_union_impl<L<T...>>
+{
+    using type = L<T...>;
+};
+
+template<template<class...> class L1, class... T1, template<class...> class L2, class... T2> struct mp_set_union_impl<L1<T1...>, L2<T2...>>
+{
+    using type = mp_set_push_back<L1<T1...>, T2...>;
+};
+
+template<class L1, class... L> using mp_set_union_ = typename mp_set_union_impl<L1, mp_append<mp_list<>, L...>>::type;
+
+template<class L1, class L2, class L3, class... L> struct mp_set_union_impl<L1, L2, L3, L...>: mp_defer<mp_set_union_, L1, L2, L3, L...>
+{
+};
+
+} // namespace detail
+
+template<class... L> using mp_set_union = typename detail::mp_set_union_impl<L...>::type;
+
 } // namespace mp11
 } // namespace boost
 
diff --git a/test/Jamfile b/test/Jamfile
index 5c9d59a..545a567 100644
--- a/test/Jamfile
+++ b/test/Jamfile
@@ -132,6 +132,8 @@ run mp_set_contains.cpp ;
 run mp_set_push_back.cpp ;
 run mp_set_push_front.cpp ;
 run mp_is_set.cpp ;
+run mp_set_union.cpp ;
+run mp_set_union_sf.cpp ;
 
 # function
 run mp_all.cpp ;
diff --git a/test/mp_set_push_back.cpp b/test/mp_set_push_back.cpp
index 0855536..279140e 100644
--- a/test/mp_set_push_back.cpp
+++ b/test/mp_set_push_back.cpp
@@ -1,5 +1,5 @@
 
-//  Copyright 2015 Peter Dimov.
+// Copyright 2015 Peter Dimov.
 //
 // Distributed under the Boost Software License, Version 1.0.
 //
diff --git a/test/mp_set_union.cpp b/test/mp_set_union.cpp
new file mode 100644
index 0000000..0811d29
--- /dev/null
+++ b/test/mp_set_union.cpp
@@ -0,0 +1,55 @@
+
+// Copyright 2019 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/set.hpp>
+#include <boost/mp11/list.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+#include <tuple>
+#include <utility>
+
+int main()
+{
+    using boost::mp11::mp_list;
+    using boost::mp11::mp_set_union;
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<>, mp_list<>>));
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<>>, mp_list<>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<void>>, mp_list<void>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<void, int>>, mp_list<void, int>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<void, int, float>>, mp_list<void, int, float>>));
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<>>, std::tuple<>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<void>>, std::tuple<void>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<void, int>>, std::tuple<void, int>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<void, int, float>>, std::tuple<void, int, float>>));
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<>, std::pair<float, int>>, mp_list<float, int>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<void>, std::pair<float, int>>, mp_list<void, float, int>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<void, int>, std::pair<float, int>>, mp_list<void, int, float>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<void, int, float>, std::pair<float, int>>, mp_list<void, int, float>>));
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<>, mp_list<>, std::pair<float, int>>, std::tuple<float, int>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<void>, mp_list<double>, std::pair<float, int>>, std::tuple<void, double, float, int>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<void, int>, mp_list<double, int>, std::pair<float, int>>, std::tuple<void, int, double, float>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<void, int, float>, mp_list<double, int, float>, std::pair<float, int>>, std::tuple<void, int, float, double>>));
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<>, std::pair<float, float>, std::pair<int, int>>, mp_list<float, int>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<void>, std::pair<float, float>, std::pair<int, int>>, mp_list<void, float, int>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<void, int>, std::pair<float, float>, std::pair<int, int>>, mp_list<void, int, float>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<mp_list<void, int, float>, std::pair<float, float>, std::pair<int, int>>, mp_list<void, int, float>>));
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<>, std::pair<float, float>, std::pair<int, int>, std::pair<void, void>>, std::tuple<float, int, void>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<void>, std::pair<float, float>, std::pair<int, int>, std::pair<void, void>>, std::tuple<void, float, int>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<void, int>, std::pair<float, float>, std::pair<int, int>, std::pair<void, void>>, std::tuple<void, int, float>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_set_union<std::tuple<void, int, float>, std::pair<float, float>, std::pair<int, int>, std::pair<void, void>>, std::tuple<void, int, float>>));
+
+    return boost::report_errors();
+}
diff --git a/test/mp_set_union_sf.cpp b/test/mp_set_union_sf.cpp
new file mode 100644
index 0000000..badf793
--- /dev/null
+++ b/test/mp_set_union_sf.cpp
@@ -0,0 +1,32 @@
+
+// Copyright 2019 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/set.hpp>
+#include <boost/mp11/utility.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+int main()
+{
+    using boost::mp11::mp_set_union;
+    using boost::mp11::mp_valid;
+    using boost::mp11::mp_list;
+
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_union, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_union, void, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_union, void, void, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_union, void, void, void, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_union, void, void, void, void, void>));
+
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_union, mp_list<>, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_union, mp_list<>, mp_list<>, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_union, mp_list<>, mp_list<>, mp_list<>, void>));
+    BOOST_TEST_TRAIT_FALSE((mp_valid<mp_set_union, mp_list<>, mp_list<>, mp_list<>, mp_list<>, void>));
+
+    return boost::report_errors();
+}