AMDG All comments are based on revision 55787. isotropy.hpp:overall There seems to be a fair amount of duplication with boost::enable_if, requires, and is_same_SFINAE. isotropy.hpp:194 I think that all arithmetic types should be supported either through enumerating all specializations or by explicit metaprogramming: template<class T> struct geometry_concept : mpl::if_<is_arithmetic<T> , coordinate_concept , undefined_concept
{}; Also, it would be nice to be able to use a nested typedef instead of specializing geometry_traits. (Think of the way std::iterator_traits works.) This works better with inheritance, since nested typedefs are inherited, but specializations are not. Since you seem to want the absence of any specialization to be detectable, it would have to be implemented something like: BOOST_MPL_HAS_XXX_TRAIT_DEF(geometry_concept_type); template<class T> struct get_geometry_concept_type { typedef typename T::geometry_concept_type type; }; template<class T> struct geometry_concept : mpl::eval_if<has_geometry_concept_type<T> , get_geometry_concept_type<T> , mpl::identity<undefined_concept> > {}; isotropy.hpp:205 requires is too generic a name. It should be something like enable_if_same. isotropy.hpp:205 This #ifdef is a little odd. I'm assuming that SFINAE is not strictly needed in gtl_if, but it allows extra short-circuiting when possible? In addition, since the problems is specific to msvc, not to win32, the test should be #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1500)) (BOOST_MSVC exists because detecing msvc accurately in the preprocessor is a pain, if I remember correctly) isotropy.hpp:308 What does y_c_edist mean, and why are you including a constant in the gtl_and for euclidean_distance? isotropy.hpp:328 s/garenteed/guaranteed/ isotropy.hpp:385 This seems excessively clever compared to a condition. isotropy.hpp:464-470 These functions need no be declared inline or they will cause link errors when included in more than one translation unit. isotropy.hpp:464 So, WEST and SOUTH become LOW and NORTH and EAST become HIGH? Is this conversion really a good idea? isotropy.hpp:528 UP and DOWN are missing from this list. isotropy.hpp:535-541 More functions that need to be inline. In Christ, Steven Watanabe