[boost] proto "boolean" laws (was Re: proto::tag naming convention

From: Larry Evans (cppljevans_at_[hidden])
Date: 2007-04-29 11:44:47

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_,....