Add mp_map_replace.

include/boost/mp11/algorithm.hpp

@@ -48,8 +48,6 @@ namespace detail
 
 template<template<class...> class F, class... L> struct mp_transform_impl;
 
-template<template<class...> class F, class... L> using mp_transform = typename mp_transform_impl<F, L...>::type;
-
 template<template<class...> class F, template<class...> class L, class... T> struct mp_transform_impl<F, L<T...>>
 {
     using type = L<F<T>...>;

include/boost/mp11/map.hpp

@@ -12,6 +12,7 @@
 #include <boost/mp11/list.hpp>
 #include <boost/mp11/integral.hpp>
 #include <boost/mp11/utility.hpp>
+#include <boost/mp11/algorithm.hpp>
 #include <type_traits>
 
 namespace boost
@@ -24,6 +25,26 @@ template<class M, class K> using mp_map_contains = mp_not<std::is_same<mp_map_fi
 template<class M, class T> using mp_map_insert = mp_if< mp_map_contains<M, mp_first<T>>, M, mp_push_back<M, T> >;
 
 // mp_map_replace<M, T>
+namespace detail
+{
+
+template<class M, class T> struct mp_map_replace_impl;
+
+template<template<class...> class M, class... U, class T> struct mp_map_replace_impl<M<U...>, T>
+{
+    using K = mp_first<T>;
+
+    // mp_replace_if is inlined here using a struct _f because of msvc-14.0
+
+    template<class V> struct _f { using type = mp_if< std::is_same<mp_first<V>, K>, T, V >; };
+
+    using type = mp_if< mp_map_contains<M<U...>, K>, M<typename _f<U>::type...>, M<U..., T> >;
+};
+
+} // namespace detail
+
+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>