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workaround for VC7.1 getting confused with optional and variant boost::get functions

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[SVN r37337]
This commit is contained in:
Joel de Guzman
2007-04-02 13:20:16 +00:00
parent 0913d82b43
commit 6a01312869
1 changed files with 22 additions and 6 deletions
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28
include/boost/fusion/sequence/adapted/variant/variant_iterator.hpp
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@ -2,7 +2,7 @@
Copyright (c) 2001-2006 Joel de Guzman
Copyright (c) 2005-2006 Dan Marsden
Distributed under the Boost Software License, Version 1.0. (See accompanying
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_FUSION_VARIANT_ITERATOR_12112006_1617)
@ -19,8 +19,9 @@
#include <boost/type_traits/add_const.hpp>
#include <boost/type_traits/add_reference.hpp>
#include <boost/variant/get.hpp>
#include <boost/detail/workaround.hpp>
namespace boost { namespace fusion
namespace boost { namespace fusion
{
struct forward_traversal_tag;
@ -39,7 +40,7 @@ namespace boost { namespace fusion
struct next
{
typedef variant_iterator<
typename Iterator::variant_type,
typename Iterator::variant_type,
typename mpl::next<typename Iterator::iterator>::type> type;
static type
@ -73,18 +74,32 @@ namespace boost { namespace fusion
template <typename Iterator>
struct deref
{
typedef typename
typedef typename
mpl::eval_if<
is_const<typename Iterator::variant_type>
, add_const<typename mpl::deref<typename Iterator::iterator>::type>
, mpl::deref<typename Iterator::iterator>
>::type
>::type
value_type;
typedef typename
typedef typename
add_reference<value_type>::type
type;
#if BOOST_WORKAROUND(BOOST_MSVC, < 1400)
// for some unknown reason (compiler bug) VC7.1 gets confused with
// variant and optional get functions.
static type
call(Iterator const & it)
{
boost::detail::variant::get_visitor<type> v;
typedef typename mpl::deref<typename Iterator::iterator>::type type;
if (type* result = it.var_.apply_visitor(v))
return *result;
it.var_ = type(); // prime the variant
return *it.var_.apply_visitor(v); // no-throw!
}
#else
static type
call(Iterator const & it)
{
@ -94,6 +109,7 @@ namespace boost { namespace fusion
it.var_ = type(); // prime the variant
return *boost::get<type>(&it.var_); // no-throw!
}
#endif
};
};
}}