[boost] About a Ratio/MPL submodule and removing dependencies from Ratio/Chrono on MPL.

Subject: [boost] About a Ratio/MPL submodule and removing dependencies from Ratio/Chrono on MPL.
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2015-01-10 11:15:20

Hi,

Boost.Ratio has a logical submodule providing an extension to the 
standard see boost::ratio as an MPL type adding
struct rational_c_tag : int_<10> {};

This submodule could be moved to the subdirectory of libs/ratio/mpl so 
that the users of boost::ratio, shouldn't depend on MPL.

Boost.Chrono depends already on MPL, but the dependencies are really 
minor - see below (and can be replaced by StaticAssert and TypeTraits, 
so that this dependency could be removed also.

Do you think removing the dependencies of Boost.Ratio and Boost.Chrono 
on Boost MPL has value?

Best,
Vicente

P.S. I know that currently TypeTraits depends on MPL, but we expect to 
resolve this dependency already.

      |<boost/mpl/assert.hpp>|

  * from |<boost/chrono/detail/static_assert.hpp>|

      |<boost/mpl/bool.hpp>|

  * from |<boost/chrono/detail/static_assert.hpp>|

      |<boost/mpl/if.hpp>|

  * from |<boost/chrono/io/duration_get.hpp>|
  * from |<boost/chrono/io_v1/chrono_io.hpp>|

      |<boost/mpl/logical.hpp>|

  * from |<boost/chrono/detail/is_evenly_divisible_by.hpp>|
  * from |<boost/chrono/duration.hpp>|