Re: [boost] [TypeTraits] is it possible to addsomething toboost.type_traits?

From: John Maddock (john_at_[hidden])
Date: 2008-08-07 07:07:35

frederic.bron_at_[hidden] wrote:
>> This has come up often enough that I think this is an excellent
>> idea: I'd be happy to help with macro usage and other details, but
>> the most important thing is for some docs and tests to get written
>> :-)
>
> OK, I obtained so much from boost that I agree to try to do the job
> my-self with some help.
> As I have never done this before, could you give me a
> procedure/formats to follow?

OK, first off there's an email invitaion to the Sandbox on it's way, once 
you're signed up then checkout using:

svn co https://svn.boost.org/svn/boost/sandbox [local-path]

and you'll find a copy of the type_traits lib under /type_traits/.

I've already added the two traits I was working on to this, feel free to add 
yours as well.

Procedure wise, if you can follow the existing structure that would be 
great: use one header per trait and one one .cpp file for each trait test 
etc.

For these traits, can we boilerplate the whole thing so that defining a 
trait for any binary operator is just something like:

#define BOOST_TT_TRAIT_NAME is_equality_comparible
#define BOOST_TT_TRAIT_OP ==
#include <boost/type_traits/detail/binary_op_traits.hpp>

??  Maybe the same for the tests as well if they're very repetitive?

With regard to macro usage, the easiest way is to define say for example 
boost::detail::is_equality_comparible_imp with a member "value" that is 
either true or false, and then add:

BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_equality_comparible,T,::boost::detail::is_equality_comparible<T>::value)

To take care of the MPL etc support.

Docs require quickbook and xslt support, installation instructions here: 
http://www.boost.org/doc/libs/1_35_0/tools/quickbook/doc/html/quickbook/install.html

Try making sure that you can build the existing docs, and then ping for help 
if you need it with the quickbook formatting: if you copy an existing traits 
class and modify that it should be fairly obvious I hope!

HTH, John.