I'm looking into the possibilities of using Boost.Parameter to introduce extra user-friendliness to a part of the numeric-bindings libraries (in this particular case, bindings for BLAS and LAPACK). Boost.Parameter looks like it is exactly what I need, making it easy to write functions with a couple of required, and many optional parameters. What I couldn't immediately catch from the documentation, is what the types of the passed arguments are of a BOOST_PARAMETER_FUNCTION. E.g., the example in section 2.1.4 says BOOST_PARAMETER_FUNCTION( [snip] ) { // ... body of function goes here... // use graph, visitor, index_map, and color_map } but it is not clear to me is how to easily get to the type of graph, visitor, etc., in the body of the function. Thanks in advance, Kind regards, Rutger ter Borg