1 files changed, 49 insertions, 0 deletions
diff --git a/boost/spirit/home/x3/support/utility/lambda_visitor.hpp b/boost/spirit/home/x3/support/utility/lambda_visitor.hpp
new file mode 100644
index 0000000000..83e1d2f046
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+++ b/boost/spirit/home/x3/support/utility/lambda_visitor.hpp
@@ -0,0 +1,49 @@
+/*=============================================================================
+    Copyright (c) 2014 Joel de Guzman
+
+    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(BOOST_SPIRIT_X3_LAMBDA_VISITOR_MAY_19_2014_1116AM)
+#define BOOST_SPIRIT_X3_LAMBDA_VISITOR_MAY_19_2014_1116AM
+
+namespace boost { namespace spirit { namespace x3
+{
+    template <typename RT, typename... Lambdas>
+    struct lambda_visitor;
+
+    template <typename RT, typename F, typename... Lambdas>
+    struct lambda_visitor<RT, F, Lambdas...> : F, lambda_visitor<RT, Lambdas...>
+    {
+        typedef lambda_visitor<RT , Lambdas...> base_type;
+        using F::operator();
+        using base_type::operator();
+        lambda_visitor(F f, Lambdas... lambdas)
+          : F(f), base_type(lambdas...)
+        {}
+    };
+
+    template <typename RT, typename F>
+    struct lambda_visitor<RT, F> : F
+    {
+        typedef RT result_type;
+        using F::operator();
+        lambda_visitor(F f)
+          : F(f)
+        {}
+    };
+
+    template <typename RT>
+    struct lambda_visitor<RT>
+    {
+        typedef RT result_type;
+    };
+
+    template <typename RT, typename... Lambdas>
+    lambda_visitor<RT, Lambdas...> make_lambda_visitor(Lambdas... lambdas)
+    {
+        return { lambdas... };
+    }
+}}}
+
+#endif