AMDG Jesse Perla wrote:
I have a class template with a large number of potential template parameters where I would like to use boost parameter. I understand that I can use integers with the int_<> wrapper, but is there any trick or design pattern to allow template template's? The problem is that I have class templates such as an interpolator which will take in a type and a dimension size, and a variety of function objects of the same type. If I can't use template templates, I am not sure how to make the design sane. For example, right now I have something like:
template<int Dimension, class T = double, template <int Dim2, class T> template Interpolator = cubic_spline> class DPP;
I don't think I can write a free function to solve the instantiation difficulty since many of the types are only used internally and I couldn't use function template argument deduction.
Use mpl::lamdba expressions. First you need to wrap any templates that take non type template parameters. For example. template<class Dim1, class Dim> class make_cubic_spline { typedef cubic_spline<Dim1::value, Dim> type; }; Then, the default argument for Interpolator can be make_cubic_spline<boost::mpl::_1, boost::mpl::_2>. When you need to get a real type, use mpl::apply: typedef boost::mpl::apply<Interpolator, mpl::int_<2>, double>::type interpolator_instance; In Christ, Steven Watanabe