Re: [Boost-users] [MPL] Filtering a sequence to leave only most-derived types

Rutger ter Borg writes:

Not sure, but I would do something like

typedef mpl::vector< A, B, C > m_vec;

typedef mpl::sort< m_vec, boost::is_base_of< mpl::_1, mpl::_2 >

...

::type sorted_type;

typedef mpl::unique< sorted_type, boost::is_base_of< mpl::_1, mpl::_2 >

...

::type unique_type;

Thank you, I got to the solution with this. I considered using sort+unique at first, but dismissed it because the predicate does not define a total order, and because is_base_of is not a proper equivalence.. But apparently it works anyway. I just had to reverse the condition (i.e. define a is_derived_from metafunction). Sebastian