Add mp_find_if_q

doc/mp11/algorithm.adoc

@@ -541,6 +541,12 @@ is `mp_size<L>`.
 `mp_find_f<L, P>` is an alias for `mp_size_t<I>`, where `I` is the zero-based index of the first element `T` in `L` for which
 `mp_to_bool<P<T>>` is `mp_true`. If there is no such element, `mp_find_if<L, P>` is `mp_size<L>`.
 
+## mp_find_if_q<L, Q>
+
+    template<class L, class Q> using mp_find_if_q = mp_find_if<L, Q::template fn>;
+
+As `mp_find_if`, but takes a quoted metafunction.
+
 ## mp_reverse<L>
 
     template<class L> using mp_reverse = /*...*/;

include/boost/mp11/algorithm.hpp

@@ -729,6 +729,7 @@ template<template<class...> class L, class T1, class... T, template<class...> cl
 } // namespace detail
 
 template<class L, template<class...> class P> using mp_find_if = typename detail::mp_find_if_impl<L, P>::type;
+template<class L, class Q> using mp_find_if_q = mp_find_if<L, Q::template fn>;
 
 // mp_reverse<L>
 namespace detail

test/Jamfile

@@ -67,6 +67,7 @@ run mp_sort.cpp ;
 run mp_sort_q.cpp ;
 run mp_find.cpp ;
 run mp_find_if.cpp ;
+run mp_find_if_q.cpp ;
 run mp_reverse.cpp ;
 run mp_fold.cpp ;
 run mp_fold_q.cpp ;

test/mp_find_if_q.cpp

@@ -0,0 +1,61 @@
+
+// Copyright 2015, 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/mp11/integral.hpp>
+#include <boost/mp11/utility.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+#include <tuple>
+#include <utility>
+
+struct X1 {};
+
+int main()
+{
+    using boost::mp11::mp_list;
+    using boost::mp11::mp_find_if_q;
+    using boost::mp11::mp_size_t;
+    using boost::mp11::mp_quote;
+
+    {
+        using L1 = mp_list<>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_if_q<L1, mp_quote<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_if_q<L2, mp_quote<std::is_volatile>>, mp_size_t<6>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_if_q<L2, mp_quote<std::is_const>>, mp_size_t<1>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_if_q<L2, mp_quote<std::is_pointer>>, mp_size_t<3>>));
+    }
+
+    {
+        using L1 = std::tuple<>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_if_q<L1, mp_quote<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_if_q<L2, mp_quote<std::is_volatile>>, mp_size_t<6>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_if_q<L2, mp_quote<std::is_const>>, mp_size_t<1>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_if_q<L2, mp_quote<std::is_pointer>>, mp_size_t<3>>));
+    }
+
+    {
+        using L2 = std::pair<X1 const, X1*>;
+
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_if_q<L2, mp_quote<std::is_volatile>>, mp_size_t<2>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_if_q<L2, mp_quote<std::is_const>>, mp_size_t<0>>));
+        BOOST_TEST_TRAIT_TRUE((std::is_same<mp_find_if_q<L2, mp_quote<std::is_pointer>>, mp_size_t<1>>));
+    }
+
+    return boost::report_errors();
+}