Re: [boost] New dependency report

Subject: Re: [boost] New dependency report
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2014-06-09 03:50:31

Le 09/06/14 00:46, Peter Dimov a écrit :
> Andrey Semashev wrote
>> mpl::bool_ is not the only thing TypeTraits uses from MPL, so this 
>> dependency won't go that easily.
>
> The list appears long, ...
>
> http://www.pdimov.com/tmp/report-b932921/type_traits.html#mpl
>
> ... but most of the nontrivial metaprogramming is done by common_type. 
> The other contenders are floating_point_promotion and 
> detail/template_arity_spec.
|The floating_point_promotion dependency is only if 
BOOST_NO_CV_SPECIALIZATIONS is defined.
Do we support compiler defining this?

$ grep -r BOOST_NO_CV_SPECIALIZATIONS *
boost/config/compiler/borland.hpp:#  define BOOST_NO_CV_SPECIALIZATIONS
boost/config/compiler/mpw.hpp:#  define BOOST_NO_CV_SPECIALIZATIONS
boost/config/suffix.hpp:#  if defined(BOOST_NO_CV_SPECIALIZATIONS) \

The detail/template_arity_spec dependency more complex.

<boost/mpl/aux_/config/lambda.hpp>
     from <boost/type_traits/detail/template_arity_spec.hpp>
<boost/mpl/aux_/config/overload_resolution.hpp>
     from <boost/type_traits/detail/template_arity_spec.hpp>
<boost/mpl/aux_/preprocessor/params.hpp>
     from <boost/type_traits/detail/template_arity_spec.hpp>
<boost/mpl/aux_/template_arity_fwd.hpp>
     from <boost/type_traits/detail/template_arity_spec.hpp>

If we had simplified version of integral_constant, conditional, and_, 
or_, boo_, int_

The following dependencies could be resolved
<boost/mpl/and.hpp>

     from <boost/type_traits/is_virtual_base_of.hpp>

<boost/mpl/bool.hpp>

     from <boost/type_traits/detail/bool_trait_def.hpp>
     from <boost/type_traits/integral_constant.hpp>

refactor integral_constant.hpp and  bool_trait_def.hpp and to don't 
depend on mpl/bool.hpp, but on type_traits_core/integral_constant.hpp.

<boost/mpl/if.hpp>

     from <boost/type_traits/conditional.hpp>

Define it independently of mpl/if.hpp. type_traits_core/conditional.hpp.

     from <boost/type_traits/make_signed.hpp>
     from <boost/type_traits/make_unsigned.hpp>
     from <boost/type_traits/type_with_alignment.hpp>

Refactor them to use conditional

<boost/mpl/int.hpp>

     from <boost/type_traits/detail/template_arity_spec.hpp>
     from <boost/type_traits/floating_point_promotion.hpp>

Make use directly of integral_constant<int,N> or define a 
type_traits::int_<N>
<boost/mpl/integral_c.hpp>

     from <boost/type_traits/integral_constant.hpp>

Don't use any more intergral_c. Use type_traits_core/integral_constant.hpp
<boost/mpl/not.hpp>

     from <boost/type_traits/is_virtual_base_of.hpp>

Add type_traits_core/not.hpp

<boost/mpl/size_t.hpp>

     from <boost/type_traits/detail/size_t_trait_def.hpp>

Use type_traits_core/integral_constant.hpp
There are yet these dependencies to resolve
<boost/mpl/aux_/lambda_support.hpp>

     from <boost/type_traits/detail/bool_trait_def.hpp>
     from <boost/type_traits/detail/size_t_trait_def.hpp>
     from <boost/type_traits/detail/type_trait_def.hpp>

<boost/mpl/eval_if.hpp>

     from <boost/aligned_storage.hpp>
     from <boost/type_traits/decay.hpp>
     from <boost/type_traits/integral_promotion.hpp>

<boost/mpl/identity.hpp>

     from <boost/aligned_storage.hpp>
     from <boost/type_traits/decay.hpp>
     from <boost/type_traits/integral_promotion.hpp>|
>
> The reverse,
>
> http://www.pdimov.com/tmp/report-b932921/mpl.html#type_traits
>
> looks breakable as well.

How do you want to break it? Duplicating what is used?

Best,
Vicente