Subject: Re: [boost] [TTI] Review for The Type Traits Introspection library by Edward Diener **extended**
From: Jeffrey Lee Hellrung, Jr. (jeffrey.hellrung_at_[hidden])
Date: 2011-07-17 02:21:53
On Sat, Jul 16, 2011 at 11:02 PM, Joel falcou <joel.falcou_at_[hidden]> wrote:
> On 17/07/11 04:58, Jeffrey Lee Hellrung, Jr. wrote:
>> * I *think* all generated metafunctions should also expose a nested "type"
>> typedef in addition to a nested "value" static bool in order to be fully
>> Boost.MPL compatible, but...I'm not sure on this one. For some reason,
>> always followed this practice, I think because it allows has_type_xxx<T>
>> be used as a nullary Boost.MPL metafunction. Can someone comment on this?
> Yes, could be nice to have as it will make the metafunction proper nullary
> MPL one. I suggest findign a way to inherit from boost::mpl::bool_ whenever
I think inheritance might be inconvenient in this case, as I'm guessing (I
haven't yet looked at the implementation) the value member is computed as
value = sizeof( ... ) == sizeof( ... );
Probably sufficient to
BOOST_STATIC_CONSTANT( bool, value = ... );
typedef this_metafunction_name type; // 1
typedef boost::integral_constant< bool, value > type; // 2
typedef boost::mpl::bool_< value > type; // 3
where I think any of 1, 2, or 3 is fine.
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