Toon Knapen <toon.knapen@fft.be> writes:
Matthias Troyer wrote:
How would you do a BOOST_WORKAROUND in a template code where you might not know the value of the static constant? I think that any constant depending on a template parameter will still have to be treated like it is done now.
Sorry but I fail to understand what you are saying. Anyway what I suggest is to use BOOST_WORKAROUND for implementing the enum-trick wherever BOOST_STATIC_CONSTANT would use the enum-trick in case BOOST_NO_INCLASS_MEMBER_INITIALISATION would have been defined.
Ultimately I think the right answer is to use mpl::integral_c<some_type, some_value> or mpl::bool_<some_value> etc. everywhere as Paul Mensonides suggested. One reason is that it centralizes the out-of-line static member definitions. I'm just not sure how it interacts with all the low-level hacks needed for broken compilers. To get the ::value member (admittedly this is just a convenience) into a metafunction you have to use forwarding via inheritance: template <class T> struct some_trait : mpl::bool_<(some-calculation-using-T)> {}; so it may mean breaking down implementations this way: template <class T> struct some_trait_impl { typedef mpl::bool_<(some-calculation-using-T)> type; }; template <class T> struct some_trait : some_trait_impl<T>::type {}; But I truly believe this is the optimal approach. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com