filter

Returns the result type of filter_if given the sequence and unary MPL Lambda Expression predicate type.

template<
    typename Sequence,
    typename Pred
    >
struct filter_if
{
    typedef unspecified type;
};

Parameter	Requirement	Description
`Sequence`	A model of Forward Sequence	Operation's argument
`Pred`	A unary MPL Lambda Expression	Type to retain

result_of::filter_if<Sequence, Pred>::type

Return type: A model of Forward Sequence.

Semantics: Returns a sequence containing the elements of Sequence for which Pred evaluates to boost::mpl::true_.

Constant.

#include <boost/fusion/algorithm/transformation/filter_if.hpp>