Re: [boost] named template parameters using mpl

From: David Abrahams (dave_at_[hidden])
Date: 2003-02-01 16:48:48

"Jonathan Wang" <babysloth_at_[hidden]> writes:

> Thanks for the url of use of BOOST_MPL_AUX_LAMBDA_SUPPORT.
> Why not more in the documetation :-)

Aleksey is working on that as I type.

> What do you mean by "a single framework could be used to handle both approaches"?

I mean a library which would allow you to extract optional types
parameters based on either their wrapper templates ("Color_is<...>")
or on a predicate (e.g. pick the one for which is_class<T>::value is
true).

> Mixing NTPs and ordinary ones is quite interesting. What I present here is
>
> 	mpl::vector<Model_is<gl>, Color_is<red>, ...>
>
> and we can use
>
>     mpl::vector<glx, Transmission_is<automatic> >
>
> to update it. The users can decide whether to convert glx to
> Model_is<glx> implicitly is allowed. And here it're more like a type
> property map, but properties is presented as templates rather than
> types.

That too.

-- 
                       David Abrahams
   dave_at_[hidden] * http://www.boost-consulting.com
Boost support, enhancements, training, and commercial distribution