Add boost::variant

boost/variant/detail/make_variant_list.hpp

@@ -0,0 +1,73 @@
+//-----------------------------------------------------------------------------
+// boost variant/detail/make_variant_list.hpp header file
+// See http://www.boost.org for updates, documentation, and revision history.
+//-----------------------------------------------------------------------------
+//
+// Copyright (c) 2002-2003 Eric Friedman, Itay Maman
+// Copyright (c) 2013 Antony Polukhin
+//
+// 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_DETAIL_MAKE_VARIANT_LIST_HPP
+#define BOOST_VARIANT_DETAIL_MAKE_VARIANT_LIST_HPP
+
+#include "boost/variant/variant_fwd.hpp"
+
+#include "boost/mpl/list.hpp"
+#include "boost/preprocessor/cat.hpp"
+#include "boost/preprocessor/enum.hpp"
+
+namespace boost {
+namespace detail { namespace variant {
+
+///////////////////////////////////////////////////////////////////////////////
+// (detail) metafunction make_variant_list
+//
+// Provides a MPL-compatible sequence with the specified non-void types
+// as arguments.
+//
+// Rationale: see class template convert_void (variant_fwd.hpp) and using-
+// declaration workaround (below).
+//
+
+#if !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
+
+template < typename... T >
+struct make_variant_list
+{
+    typedef typename mpl::list< T... >::type type;
+};
+
+#else // defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
+
+template < BOOST_VARIANT_ENUM_PARAMS(typename T) >
+struct make_variant_list
+{
+public: // metafunction result
+
+    // [Define a macro to convert any void(NN) tags to mpl::void...]
+#   define BOOST_VARIANT_AUX_CONVERT_VOID(z, N,_)  \
+        typename convert_void< BOOST_PP_CAT(T,N) >::type
+
+    // [...so that the specified types can be passed to mpl::list...]
+    typedef typename mpl::list< 
+          BOOST_PP_ENUM(
+              BOOST_VARIANT_LIMIT_TYPES
+            , BOOST_VARIANT_AUX_CONVERT_VOID
+            , _
+            )
+        >::type type;
+
+    // [...and, finally, the conversion macro can be undefined:]
+#   undef BOOST_VARIANT_AUX_CONVERT_VOID
+
+};
+
+#endif // BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES workaround
+
+}} // namespace detail::variant
+} // namespace boost
+
+#endif // BOOST_VARIANT_DETAIL_MAKE_VARIANT_LIST_HPP