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diff --git a/boost/spirit/home/x3/operator/optional.hpp b/boost/spirit/home/x3/operator/optional.hpp
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+++ b/boost/spirit/home/x3/operator/optional.hpp
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+/*=============================================================================
+    Copyright (c) 2001-2014 Joel de Guzman
+    Copyright (c) 2001-2011 Hartmut Kaiser
+
+    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)
+=============================================================================*/
+#if !defined(SPIRIT_OPTIONAL_MARCH_23_2007_1117PM)
+#define SPIRIT_OPTIONAL_MARCH_23_2007_1117PM
+
+#if defined(_MSC_VER)
+#pragma once
+#endif
+
+#include <boost/spirit/home/x3/core/proxy.hpp>
+#include <boost/spirit/home/x3/core/detail/parse_into_container.hpp>
+#include <boost/spirit/home/x3/support/traits/attribute_of.hpp>
+#include <boost/spirit/home/x3/support/traits/move_to.hpp>
+#include <boost/spirit/home/x3/support/traits/optional_traits.hpp>
+#include <boost/spirit/home/x3/support/traits/attribute_category.hpp>
+
+namespace boost { namespace spirit { namespace x3
+{
+    template <typename Subject>
+    struct optional : proxy<Subject, optional<Subject>>
+    {
+        typedef proxy<Subject, optional<Subject>> base_type;
+        static bool const handles_container = true;
+
+        optional(Subject const& subject)
+          : base_type(subject) {}
+
+        using base_type::parse_subject;
+
+        // Attribute is a container
+        template <typename Iterator, typename Context
+          , typename RContext, typename Attribute>
+        bool parse_subject(Iterator& first, Iterator const& last
+          , Context const& context, RContext& rcontext, Attribute& attr
+          , traits::container_attribute) const
+        {
+            detail::parse_into_container(
+                this->subject, first, last, context, rcontext, attr);
+            return true;
+        }
+
+        // Attribute is an optional
+        template <typename Iterator, typename Context
+          , typename RContext, typename Attribute>
+        bool parse_subject(Iterator& first, Iterator const& last
+          , Context const& context, RContext& rcontext, Attribute& attr
+          , traits::optional_attribute) const
+        {
+            typedef typename
+                x3::traits::optional_value<Attribute>::type
+            value_type;
+
+            // create a local value
+            value_type val = value_type();
+
+            if (this->subject.parse(first, last, context, rcontext, val))
+            {
+                // assign the parsed value into our attribute
+                x3::traits::move_to(val, attr);
+            }
+            return true;
+        }
+    };
+
+    template <typename Subject>
+    inline optional<typename extension::as_parser<Subject>::value_type>
+    operator-(Subject const& subject)
+    {
+        return {as_parser(subject)};
+    }
+}}}
+
+namespace boost { namespace spirit { namespace x3 { namespace traits
+{
+    template <typename Subject, typename Context>
+    struct attribute_of<x3::optional<Subject>, Context>
+        : build_optional<
+            typename attribute_of<Subject, Context>::type> {};
+}}}}
+
+#endif