Add mp_find_index_if.

include/boost/mp11/algorithm.hpp

@@ -558,6 +558,60 @@ template<template<class...> class L, class T1, class... T, class V> struct mp_fi
 template<class L, class V> using mp_find_index = typename detail::mp_find_index_impl<L, V>::type;
 
 // mp_find_index_if<L, P>
+namespace detail
+{
+
+template<class L, template<class...> class P> struct mp_find_index_if_impl;
+
+#if !defined( BOOST_NO_CXX11_CONSTEXPR )
+
+template<template<class...> class L, template<class...> class P> struct mp_find_index_if_impl<L<>, P>
+{
+    using type = mp_size_t<0>;
+};
+
+template<template<class...> class L, class... T, template<class...> class P> struct mp_find_index_if_impl<L<T...>, P>
+{
+    static constexpr bool _v[] = { P<T>::value... };
+    using type = mp_size_t< cx_find_index( _v, _v + sizeof...(T) ) >;
+};
+
+#else
+
+#if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, <= 1800 )
+
+template<template<class...> class L, class... T, template<class...> class P> struct mp_find_index_if_impl<L<T...>, P>
+{
+    static_assert( sizeof...(T) == 0, "T... must be empty" );
+    using type = mp_size_t<0>;
+};
+
+#else
+
+template<template<class...> class L, template<class...> class P> struct mp_find_index_if_impl<L<>, P>
+{
+    using type = mp_size_t<0>;
+};
+
+#endif
+
+template<class L, template<class...> class P> struct mp_find_index_if_impl_2
+{
+    using _r = typename mp_find_index_if_impl<L, P>::type;
+    using type = mp_size_t<1 + _r::value>;
+};
+
+template<template<class...> class L, class T1, class... T, template<class...> class P> struct mp_find_index_if_impl<L<T1, T...>, P>
+{
+    using type = typename mp_if<P<T1>, mp_identity<mp_size_t<0>>, mp_find_index_if_impl_2<mp_list<T...>, P>>::type;
+};
+
+#endif
+
+} // namespace detail
+
+template<class L, template<class...> class P> using mp_find_index_if = typename detail::mp_find_index_if_impl<L, P>::type;
+
 // mp_find<L, V>
 // mp_find_if<L, P>
 

test/Jamfile.v2

@@ -45,6 +45,7 @@ run mp_remove_if.cpp : : : $(REQ) ;
 run mp_partition.cpp : : : $(REQ) ;
 run mp_sort.cpp : : : $(REQ) ;
 run mp_find_index.cpp : : : $(REQ) ;
+run mp_find_index_if.cpp : : : $(REQ) ;
 
 # integral
 run integral.cpp : : : $(REQ) ;

test/mp_find_index_if.cpp

@@ -0,0 +1,59 @@
+
+//  Copyright 2015 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/mp11/integral.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+#include <tuple>
+#include <utility>
+
+struct X1 {};
+
+int main()
+{
+    using boost::mp_list;
+    using boost::mp_find_index_if;
+    using boost::mp_size_t;
+
+    {
+        using L1 = mp_list<>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_index_if<L1, std::is_const>, mp_size_t<0>>));
+
+        using L2 = mp_list<X1, X1 const, X1 const, X1*, X1*, X1*>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_index_if<L2, std::is_volatile>, mp_size_t<6>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_index_if<L2, std::is_const>, mp_size_t<1>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_index_if<L2, std::is_pointer>, mp_size_t<3>>));
+    }
+
+    {
+        using L1 = std::tuple<>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_index_if<L1, std::is_const>, mp_size_t<0>>));
+
+        using L2 = std::tuple<X1, X1 const, X1 const, X1*, X1*, X1*>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_index_if<L2, std::is_volatile>, mp_size_t<6>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_index_if<L2, std::is_const>, mp_size_t<1>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_index_if<L2, std::is_pointer>, mp_size_t<3>>));
+    }
+
+    {
+        using L2 = std::pair<X1 const, X1*>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_index_if<L2, std::is_volatile>, mp_size_t<2>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_index_if<L2, std::is_const>, mp_size_t<0>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_index_if<L2, std::is_pointer>, mp_size_t<1>>));
+    }
+
+    return boost::report_errors();
+}