Hello everyone. Currently only one runtime algorithm is available in MPL: for_each. I suggest to add another one: runtime_contains_if. The problem is searching through the sequence of types and find that one which satisfies some runtime predicate. Sample task: Given some base abstract class: struct base { virtual ~base(){} }; The implementation of the base could be one of the following classes: struct child1 : public base {}; struct child2 : public base {}; struct child3 : public base {}; struct child4 : public base {}; struct child5 : public base {}; Now suppose you have "base* b" and you need to find out if its concrete type is either child3 or child4 (in practise the set of types to check could be larger). I propose the following solution: 1. You write a predicate similar to STL contains_if but with template type in operator(). The concept is the same as in boost::mpl::for_each. struct child_detector { base* base_; child_detector( base* b ) : base_( b ) {} template< typename Derived_ > bool operator()( Derived_* ) { return ( 0 != dynamic_cast< Derived_* >( base_ ) ); } }; 2. You use boost::mpl::runtime_contains_if algorithm: bool type_is_special( base* b ) { typedef boost::mpl::list< child3, child4 > special_types; return boost::mpl::runtime_contains_if< special_types >( child_detector(b) ); } The implementation of the boost::mpl::runtime_contains_if is in attached runtime_contains_if.hpp. Complete example is in attached runtime_contains_if_example.cpp.