Add SCons configure checks

[senf.git] / boost_ext / boost / parameter / aux_ / tagged_argument.hpp

diff --git a/boost_ext/boost/parameter/aux_/tagged_argument.hpp b/boost_ext/boost/parameter/aux_/tagged_argument.hpp
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+++ b/boost_ext/boost/parameter/aux_/tagged_argument.hpp
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+// Copyright Daniel Wallin, David Abrahams 2005. Use, modification and
+// distribution is subject to 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)
+
+#ifndef TAGGED_ARGUMENT_050328_HPP
+#define TAGGED_ARGUMENT_050328_HPP
+
+#include <boost/parameter/aux_/void.hpp>
+#include <boost/parameter/aux_/arg_list.hpp>
+#include <boost/detail/is_xxx.hpp>
+
+namespace boost { namespace parameter { namespace aux {
+
+// Holds a reference to an argument of type Arg associated with
+// keyword Keyword
+    
+template <class Keyword, class Arg>
+struct tagged_argument
+{
+    typedef Keyword key_type;
+    typedef Arg value_type;
+    typedef Arg& reference;
+
+    tagged_argument(reference x) : value(x) {}
+
+    // Comma operator to compose argument list without using parameters<>.
+    // Useful for argument lists with undetermined length.
+    template <class Keyword2, class Arg2>
+    arg_list<
+        tagged_argument<Keyword, Arg>
+      , arg_list<tagged_argument<Keyword2, Arg2> > 
+    >
+    operator,(tagged_argument<Keyword2, Arg2> x) const
+    {
+        return arg_list<
+            tagged_argument<Keyword, Arg>
+          , arg_list<tagged_argument<Keyword2, Arg2> > 
+        >(
+            *this
+          , arg_list<tagged_argument<Keyword2, Arg2> >(x, empty_arg_list())
+        );
+    }
+    
+    reference value;
+};
+
+// Defines a metafunction, is_tagged_argument, that identifies
+// tagged_argument specializations.
+BOOST_DETAIL_IS_XXX_DEF(tagged_argument,tagged_argument,2)
+
+}}} // namespace boost::parameter::aux
+
+#endif // TAGGED_ARGUMENT_050328_HPP
+