variant as a fusion sequence

[SVN r36014]

include/boost/fusion/sequence/adapted.hpp

@@ -13,5 +13,6 @@
 #include <boost/fusion/sequence/adapted/std_pair.hpp>
 #include <boost/fusion/sequence/adapted/array.hpp>
 #include <boost/fusion/sequence/adapted/mpl.hpp>
+#include <boost/fusion/sequence/adapted/variant.hpp>
 
 #endif

include/boost/fusion/sequence/adapted/variant.hpp

@@ -0,0 +1,18 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 Joel de Guzman
+    Copyright (c) 2005-2006 Dan Marsden
+
+    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)
+==============================================================================*/
+#if !defined(BOOST_FUSION_VARIANT_12112006_1614)
+#define BOOST_FUSION_VARIANT_12112006_1614
+
+#include <boost/fusion/sequence/adapted/variant/variant_iterator.hpp>
+#include <boost/fusion/sequence/adapted/variant/tag_of.hpp>
+#include <boost/fusion/sequence/adapted/variant/detail/size_impl.hpp>
+#include <boost/fusion/sequence/adapted/variant/detail/begin_impl.hpp>
+#include <boost/fusion/sequence/adapted/variant/detail/end_impl.hpp>
+
+#endif

include/boost/fusion/sequence/adapted/variant/detail/begin_impl.hpp

@@ -0,0 +1,46 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 Joel de Guzman
+    Copyright (c) 2005-2006 Dan Marsden
+
+    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)
+==============================================================================*/
+#if !defined(BOOST_FUSION_VARIANT_BEGIN_IMPL_12112006_2137)
+#define BOOST_FUSION_VARIANT_BEGIN_IMPL_12112006_2137
+
+#include <boost/mpl/begin.hpp>
+
+namespace boost { namespace fusion {
+
+    struct variant_tag;
+
+    template<typename Seq, typename Iterator>
+    struct variant_iterator;
+
+    namespace extension
+    {
+        template<typename T>
+        struct begin_impl;
+
+        template <>
+        struct begin_impl<variant_tag>
+        {
+            template <typename Seq>
+            struct apply 
+            {
+                typedef variant_iterator<
+                    Seq, 
+                    typename mpl::begin<typename Seq::types>::type> type;
+    
+                static type
+                call(Seq& v)
+                {
+                    return type(v);
+                }
+            };
+        };
+    }
+}}
+
+#endif

include/boost/fusion/sequence/adapted/variant/detail/end_impl.hpp

@@ -0,0 +1,46 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 Joel de Guzman
+    Copyright (c) 2005-2006 Dan Marsden
+
+    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)
+==============================================================================*/
+#if !defined(BOOST_FUSION_VARIANT_END_IMPL_12112006_2137)
+#define BOOST_FUSION_VARIANT_END_IMPL_12112006_2137
+
+#include <boost/mpl/end.hpp>
+
+namespace boost { namespace fusion {
+
+    struct variant_tag;
+
+    template<typename Seq, typename Iterator>
+    struct variant_iterator;
+
+    namespace extension
+    {
+        template<typename T>
+        struct end_impl;
+
+        template <>
+        struct end_impl<variant_tag>
+        {
+            template <typename Seq>
+            struct apply 
+            {
+                typedef variant_iterator<
+                    Seq, 
+                    typename mpl::end<typename Seq::types>::type> type;
+    
+                static type
+                call(Seq& v)
+                {
+                    return type(v);
+                }
+            };
+        };
+    }
+}}
+
+#endif

include/boost/fusion/sequence/adapted/variant/detail/size_impl.hpp

@@ -0,0 +1,33 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 Joel de Guzman
+    Copyright (c) 2005-2006 Dan Marsden
+
+    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)
+==============================================================================*/
+#if !defined(BOOST_FUSION_VARIANT_SIZE_IMPL_12112006_2115)
+#define BOOST_FUSION_VARIANT_SIZE_IMPL_12112006_2115
+
+#include <boost/mpl/size.hpp>
+
+namespace boost { namespace fusion {
+
+    struct variant_tag;
+
+    namespace extension
+    {
+        template<typename T>
+        struct size_impl;
+
+        template<>
+        struct size_impl<variant_tag>
+        {
+            template<typename Sequence>
+            struct apply : mpl::size<typename Sequence::types> 
+            {};
+        };
+    }
+}}
+
+#endif

include/boost/fusion/sequence/adapted/variant/tag_of.hpp

@@ -0,0 +1,29 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 Joel de Guzman
+    Copyright (c) 2005-2006 Dan Marsden
+
+    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)
+==============================================================================*/
+#if !defined(BOOST_FUSION_VARIANT_TAG_OF_12112006_1704)
+#define BOOST_FUSION_VARIANT_TAG_OF_12112006_1704
+
+#include <boost/fusion/support/tag_of_fwd.hpp>
+#include <boost/variant/variant_fwd.hpp>
+
+namespace boost { namespace fusion 
+{
+    struct variant_tag;
+
+    namespace traits
+    {
+        template<BOOST_VARIANT_ENUM_PARAMS(typename T)>
+        struct tag_of<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> >
+        {
+            typedef variant_tag type;
+        };
+    }
+}}
+
+#endif

include/boost/fusion/sequence/adapted/variant/variant_iterator.hpp

@@ -0,0 +1,94 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 Joel de Guzman
+    Copyright (c) 2005-2006 Dan Marsden
+
+    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)
+==============================================================================*/
+#if !defined(BOOST_FUSION_VARIANT_ITERATOR_12112006_1617)
+#define BOOST_FUSION_VARIANT_ITERATOR_12112006_1617
+
+#include <boost/fusion/iterator/iterator_facade.hpp>
+
+#include <boost/mpl/next.hpp>
+#include <boost/mpl/int.hpp>
+#include <boost/mpl/distance.hpp>
+#include <boost/mpl/deref.hpp>
+#include <boost/mpl/eval_if.hpp>
+#include <boost/type_traits/is_const.hpp>
+#include <boost/type_traits/add_const.hpp>
+
+namespace boost { namespace fusion {
+
+    struct forward_traversal_tag;
+
+    template<typename Variant, typename Iterator>
+    struct variant_iterator
+        : iterator_facade<variant_iterator<Variant, Iterator>, forward_traversal_tag>
+    {
+        typedef Variant variant_type;
+        typedef Iterator iterator;
+
+        variant_iterator(Variant& var)
+            : var_(var) {}
+        Variant& var_;
+
+        template<typename Iterator>
+        struct next
+        {
+            typedef variant_iterator<
+                typename Iterator::variant_type, 
+                typename mpl::next<typename Iterator::iterator>::type> type;
+
+            static type
+            call(Iterator const& i)
+            {
+                return type(i.var_);
+            }
+        };
+
+        template<typename I1, typename I2>
+        struct distance
+            : mpl::distance<
+            typename I1::iterator,
+            typename I2::iterator>
+        {
+            typedef typename mpl::distance<
+                typename I1::iterator,
+                typename I2::iterator>::type type;
+
+            static type call(I1 const& i1, I2 const& i2)
+            {
+                return type();
+            }
+        };
+
+        template<typename Iterator>
+        struct value_of
+            : mpl::deref<typename Iterator::iterator>
+        {};
+
+        template <typename Iterator>
+        struct deref
+        {
+            typedef typename mpl::eval_if<
+                is_const<typename Iterator::variant_type>, 
+                typename add_const<typename mpl::deref<typename Iterator::iterator>::type>,
+                typename mpl::deref<typename Iterator::iterator>
+                >::type 
+            type;
+
+            static type
+            call(Iterator const & it)
+            {
+                typedef typename mpl::deref<typename Iterator::iterator>::type type;
+                type* result = get<type>(&it.var_);
+                return result ? *result : type();
+            }
+        };
+    };
+
+}}
+
+#endif