Beman Dawes wrote:
The improved type safety of the C++0x scoped enum feature is attractive, so I'd like to start using it as it becomes available in compilers.
See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2347.pdf for a description. Note that the committee changed the name from strongly typed enums to scoped enums.
See the attached for a boost/detail header that provides macro wrappers that use scoped enums if available, otherwise fall back on C++03 namespaces and unscoped enums. It lets a library write:
BOOST_SCOPED_ENUM_START(algae) { green, red, cyan }; BOOST_SCOPED_ENUM_END ... BOOST_SCOPED_ENUM(algae) sample( algae::red ); void func(BOOST_SCOPED_ENUM(algae));
and then a user can write:
sample = algae::green; func( algae::cyan );
Good plan. Thoughts: - No need to make it a ::detail! - The user needs to spell out the macro if they declare a variable; can this be avoided? - How about avoiding the _START/_END stuff with e.g. BOOST_SCOPED_ENUM_DECL(algae, green,red,cyan); (I had been under the impression that varargs macros were a gcc-ism, but I've recently discovered that they're in c99; do non-gcc C++ compilers generally allow them? I don't think we can get away with allowing only up-to-N elements in this case.) - I agree with Kjell about the double negative :-) Phil.