Re: [boost] [MPL.Math] Updated version now available

From: Arkadiy Vertleyb (vertleyb_at_[hidden])
Date: 2006-01-14 07:57:25

"Andy Little" <andy_at_[hidden]> wrote

> For each type, typeof registration is quite a heavyweight process,

Why is it heavyweight?  Registering a type is just creating a couple of
template specializations -- that's it.

> so I want to
> only register those types that I Really need to.  Currently this is not
the case
> so I get for example mpl::math::zero, mpl::math::denominator, etc etc,
etc, etc
> and the kitchen sink registered for me though I dont need registration for
the
> vast majority of these types, also bearing in mind that space in the
Typeof
> vector is limited,

What do you mean by the "space in the typeof vector"?  How is it related to
the number of registered types?

> so I dont think registering everything is a practical way to
> do it.

What do you mean by everything?  I would recommend registering types and
templates that can be present in the types used by your users.

> It must be possible for me the user  to be able to register each type
separately
> (only if it becomes necessary.)
> Of coures the problem comes then because mpl works in terms of concepts
rather
> than type-names,  so I might get a int_, a integral_c, or a long_.  , a
> rational or a simplified_rational.  I dont really know a clean  solution
to the
> problem of what to register if I use mpl, (maybe  'per concept
registration
> would be OK) but I dont think registering everything at one go is a good
> solution.

I would register your own types/templates leaving mpl types/templates to
either mpl authors or users.  Then again, you could wear an mpl hat and
register its types, but I don't think this should become a part of your
library.

Regards,
Arkadiy