diff options
Diffstat (limited to 'boost/fusion/algorithm/transformation/erase.hpp')
| -rw-r--r-- | boost/fusion/algorithm/transformation/erase.hpp | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/boost/fusion/algorithm/transformation/erase.hpp b/boost/fusion/algorithm/transformation/erase.hpp index 304ed4c51e..6ad737fd18 100644 --- a/boost/fusion/algorithm/transformation/erase.hpp +++ b/boost/fusion/algorithm/transformation/erase.hpp @@ -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; |