Add boost::variant

boost/variant/static_visitor.hpp

@@ -0,0 +1,96 @@
+//-----------------------------------------------------------------------------
+// boost variant/static_visitor.hpp header file
+// See http://www.boost.org for updates, documentation, and revision history.
+//-----------------------------------------------------------------------------
+//
+// Copyright (c) 2002-2003
+// Eric Friedman
+//
+// 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)
+
+#ifndef BOOST_VARIANT_STATIC_VISITOR_HPP
+#define BOOST_VARIANT_STATIC_VISITOR_HPP
+
+#include "boost/config.hpp"
+#include "boost/detail/workaround.hpp"
+
+#include "boost/mpl/if.hpp"
+#include "boost/type_traits/is_base_and_derived.hpp"
+
+// should be the last #include
+#include "boost/type_traits/detail/bool_trait_def.hpp"
+
+namespace boost {
+
+//////////////////////////////////////////////////////////////////////////
+// class template static_visitor
+//
+// An empty base class that typedefs the return type of a deriving static
+// visitor. The class is analogous to std::unary_function in this role.
+//
+
+namespace detail {
+
+    struct is_static_visitor_tag { };
+
+    typedef void static_visitor_default_return;
+
+} // namespace detail
+
+template <typename R = ::boost::detail::static_visitor_default_return>
+class static_visitor
+    : public detail::is_static_visitor_tag
+{
+public: // typedefs
+
+    typedef R result_type;
+
+protected: // for use as base class only
+#if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS) && !defined(BOOST_NO_CXX11_NON_PUBLIC_DEFAULTED_FUNCTIONS)
+    static_visitor() = default;
+    ~static_visitor() = default;
+#else
+    static_visitor()  BOOST_NOEXCEPT { }
+    ~static_visitor()  BOOST_NOEXCEPT { }
+#endif
+};
+
+//////////////////////////////////////////////////////////////////////////
+// metafunction is_static_visitor
+//
+// Value metafunction indicates whether the specified type derives from
+// static_visitor<...>.
+//
+// NOTE #1: This metafunction does NOT check whether the specified type
+//  fulfills the requirements of the StaticVisitor concept.
+//
+// NOTE #2: This template never needs to be specialized!
+//
+
+namespace detail {
+
+template <typename T>
+struct is_static_visitor_impl
+{
+    BOOST_STATIC_CONSTANT(bool, value = 
+        (::boost::is_base_and_derived< 
+            detail::is_static_visitor_tag,
+            T
+        >::value));
+};
+
+} // namespace detail
+
+BOOST_TT_AUX_BOOL_TRAIT_DEF1(
+      is_static_visitor
+    , T
+    , (::boost::detail::is_static_visitor_impl<T>::value)
+    )
+
+} // namespace boost
+
+#include "boost/type_traits/detail/bool_trait_undef.hpp"
+
+#endif // BOOST_VARIANT_STATIC_VISITOR_HPP