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Patches from Nathan Ridge using SFINAE to disable the Fusion algorithms for non-{Fusion sequence} types

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[SVN r78463]
This commit is contained in:
Joel de Guzman
2012-05-14 00:37:21 +00:00
parent 66e8a6d3b7
commit b63c8214d7
15 changed files with 174 additions and 24 deletions
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35
include/boost/fusion/algorithm/transformation/erase.hpp
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@ -16,6 +16,9 @@
#include <boost/fusion/sequence/intrinsic/begin.hpp>
#include <boost/fusion/sequence/intrinsic/end.hpp>
#include <boost/fusion/adapted/mpl/mpl_iterator.hpp>
#include <boost/fusion/support/is_sequence.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/mpl/if.hpp>
namespace boost { namespace fusion
{
@ -53,18 +56,38 @@ namespace boost { namespace fusion
}
};
struct use_default;
template <class T, class Default>
struct fusion_default_help
: mpl::if_<
is_same<T, use_default>
, Default
, T
>
{
};
template <
typename Sequence
, typename First
, typename Last = typename compute_erase_last<Sequence, First>::type>
, typename Last = use_default>
struct erase
{
typedef typename result_of::begin<Sequence>::type seq_first_type;
typedef typename result_of::end<Sequence>::type seq_last_type;
BOOST_STATIC_ASSERT((!result_of::equal_to<seq_first_type, seq_last_type>::value));
typedef typename convert_iterator<First>::type first_type;
typedef typename convert_iterator<Last>::type last_type;
typedef First FirstType;
typedef typename
fusion_default_help<
Last
, typename compute_erase_last<Sequence, First>::type
>::type
LastType;
typedef typename convert_iterator<FirstType>::type first_type;
typedef typename convert_iterator<LastType>::type last_type;
typedef iterator_range<seq_first_type, first_type> left_type;
typedef iterator_range<last_type, seq_last_type> right_type;
typedef joint_view<left_type, right_type> type;
@ -72,7 +95,11 @@ namespace boost { namespace fusion
}
template <typename Sequence, typename First>
typename result_of::erase<Sequence const, First>::type
typename
lazy_enable_if<
traits::is_sequence<Sequence>
, typename result_of::erase<Sequence const, First>
>::type
erase(Sequence const& seq, First const& first)
{
typedef result_of::erase<Sequence const, First> result_of;