[boost] Re: function (object) return and argument metafunctions?

From: David Abrahams (dave_at_[hidden])
Date: 2004-01-31 11:01:55

"Peter Dimov" <pdimov_at_[hidden]> writes:

> David Abrahams wrote:
>> Douglas Paul Gregor <gregod_at_[hidden]> writes:
>>
>>> Well, we could extend function_traits a bit...
>>
>> Not another multi-valued traits blob, please!  I want metafunctions.
>> The best answer might be a single metafunction returning an MPL
>> sequence of argument types.
>
> I've asked you before: a function type is a perfectly good sequence, why not
> just extend MPL to iterate over it? (Which I recall MPL "v2" already did at
> one point, to enable list(int, float, void*) to work.)

Two reasons:

  1. It's not very portable, so we can't "just" extend MPL to iterate
     over the function type

  2. It doesn't cover function objects with fixed argument lists, so
     we can't "just" extend MPL to iterate over a function type

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