[boost] MPL/lambda question

From: Arkadiy Vertleyb (vertleyb_at_[hidden])
Date: 2003-11-12 08:12:21

Hi all,

I've been actively using MPL for about 2 weeks, and I like the library a
lot.  However, I have difficulties applying/understanding the lambda
facility.  Looks like all MPL algorithms are also lambda meta-functors, by
the means of BOOST_MPL_AUX_LAMBDA_SUPPORT macro, that give them the "apply"
nested template.

I would expect conflicts between those two roles, however in most cases
there are not (I am curious why).  Still, when I am trying to use, for
example, the following meta-functor:

select1st<_2>

on a pair, my VC6 complains: error C2039: 'first' : is not a member of
'arg<2>'

Which is what I asummed in the first place -- 'first' is a member of
arg<2>::apply<...> (or arg<2>::rebind::apply<...>) -- not the arg<2>.

Can anybody to clarify the issue?

Thanks in advance,

Arkadiy