Add mp_map_erase.

include/boost/mp11/map.hpp

@@ -46,7 +46,20 @@ template<template<class...> class M, class... U, class T> struct mp_map_replace_
 template<class M, class T> using mp_map_replace = typename detail::mp_map_replace_impl<M, T>::type;
 
 // mp_map_update<M, T, F>
+
 // mp_map_erase<M, K>
+namespace detail
+{
+
+template<class M, class K> struct mp_map_erase_impl
+{
+    template<class T> using _f = std::is_same<mp_first<T>, K>;
+    using type = mp_remove_if<M, _f>;
+};
+
+} // namespace detail
+
+template<class M, class K> using mp_map_erase = typename detail::mp_map_erase_impl<M, K>::type;
 
 } // namespace boost
 

test/Jamfile.v2

@@ -1,6 +1,6 @@
 #  Boost.Mp11 Library Test Jamfile
 #
-#  Copyright 2015 Peter Dimov
+#  Copyright 2015-2017 Peter Dimov
 #
 #  Distributed under the Boost Software License, Version 1.0.
 #  See accompanying file LICENSE_1_0.txt or copy at
@@ -94,3 +94,4 @@ run mp_map_find.cpp : : : $(REQ) ;
 run mp_map_contains.cpp : : : $(REQ) ;
 run mp_map_insert.cpp : : : $(REQ) ;
 run mp_map_replace.cpp : : : $(REQ) ;
+run mp_map_erase.cpp : : : $(REQ) ;

test/mp_map_erase.cpp

@@ -0,0 +1,61 @@
+
+// Copyright 2016, 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/map.hpp>
+#include <boost/mp11/list.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+#include <tuple>
+#include <utility>
+
+int main()
+{
+    using boost::mp_map_erase;
+    using boost::mp_list;
+    using boost::mp_push_back;
+
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<mp_list<>, void>, mp_list<>>));
+    BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<std::tuple<>, int>, std::tuple<>>));
+
+    {
+        using M = mp_list<std::pair<int, int const>, std::pair<long, long const>>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, char>, M>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, int>, mp_list<std::pair<long, long const>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, long>, mp_list<std::pair<int, int const>>>));
+    }
+
+    {
+        using M = std::tuple<std::pair<int, int const>, std::pair<long, long const>>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, char>, M>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, int>, std::tuple<std::pair<long, long const>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, long>, std::tuple<std::pair<int, int const>>>));
+    }
+
+    {
+        using M = mp_list<mp_list<int>, mp_list<long, long>, mp_list<long long, long long, long long>>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, char>, M>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, int>, mp_list<mp_list<long, long>, mp_list<long long, long long, long long>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, long>, mp_list<mp_list<int>, mp_list<long long, long long, long long>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, long long>, mp_list<mp_list<int>, mp_list<long, long>>>));
+    }
+
+    {
+        using M = std::tuple<mp_list<int>, std::pair<long, long>, std::tuple<long long, long long, long long>>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, char>, M>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, int>, std::tuple<std::pair<long, long>, std::tuple<long long, long long, long long>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, long>, std::tuple<mp_list<int>, std::tuple<long long, long long, long long>>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_map_erase<M, long long>, std::tuple<mp_list<int>, std::pair<long, long>>>));
+    }
+
+    return boost::report_errors();
+}