Larry Evans wrote:
On 04/27/2007 03:25 PM, Eric Niebler wrote:
Larry Evans wrote:
why not do the following renames:
proto::_ -> proto::true_
proto::not_<_> -> proto::false_
?
No, proto::_ is a placeholder. And proto::not_<> can logically negate any grammar, not just proto::_.
Actaully, the following is what I had in mind:
namespace boost { namespace proto { struct true_ : _ {}; struct false_ : not_<true_> {};
}}//exit boost::proto namespace
Why? Because I think (I haven't tested it) the same laws for mpl::bool_ and it's associated operations:
mpl::not_ mpl::and_ mpl::or_
would apply to proto's true_, false_, not_,....
I guess I don't see how these types would be used. In what contexts would using proto::true_ make more sense than using proto::_ ? -- Eric Niebler Boost Consulting www.boost-consulting.com