Re: [boost] [type_map] Interest in container indexed by type?

From: David Abrahams (dave_at_[hidden])
Date: 2005-11-08 08:52:00

Tony D <tony_in_da_uk_at_[hidden]> writes:

> For the record, another important benefit of type_maps
> is that code can be instantiated with a type_map, and
> a template <typename T> fn(T& t) can perform
> operations on the T field in the typemap, including
> storing the function's argument, or setting it to the
> retrieved value.
>
> By way of contrast, for code instantiated with an
> arbitrary structure there's no knowledge of field
> identifiers, so equivalent field access can only be
> achieved if that structure is directly exposed through
> the API.
>
> I was curious with the MPL guys could see any use in
> having a typedef in a type_map for a mpl::vector, but 
> it's pretty clear nobody reading this gives a hoot
> about "type_map"s as described, so I'll put a sock in
> it.

Are these things any different from the ArgumentPacks created by the
Boost.Parameter library?

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com