Thanks a lot for your hint. It works perfectly. Here is the code: #include "boost/mpl/vector.hpp" #include #include using namespace std; using namespace boost; typedef mpl::vector vec_1; typedef mpl::vector vec_2; typedef mpl::vector vec_3; typedef mpl::vector mat; typedef mpl::find_if< mat, is_same< mpl::at< mpl::_1, mpl::int_<0> >, double> >::type iter; int _tmain(int argc, _TCHAR* argv[]) { BOOST_STATIC_ASSERT(( is_same< mpl::deref<iter>::type, vec_3 >::value )); return 0; }

Chris Weed wrote:

On 3/28/07, Tobias Schwinger wrote:

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Christian Henning wrote:

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Hi there, I'm trying to find a solution for looking for type vector containing a specific type. On another thread I was suggested to use at_c within the find_if algorithm. Unfortunately the code doesn't compile. Placeholder substitution won't work in templates taking non-type arguments, such as at_c.

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typedef mpl::find_ifmpl::_1,1, int> >::type iter; Try using 'at' and 'int_':

typedef find_if >, int> >::type iter;

Regards, Tobias

I am curious why at_c doesn't do the same thing. Shouldn't these be equivalent.

Yes, ideally. But it would be rather heavy, implementation-wise. You can decompose a type created by specializing a template like this: template<typename T> struct template_traits; template