[boost] Re: MPL include problem with BOOST_PP_ITERATE

From: Hugo Duncan (hugoduncan_at_[hidden])
Date: 2003-01-24 17:59:36

On Fri, 24 Jan 2003 17:01:21 -0500, David Abrahams <dave_at_[hidden]> wrote:
> Hugo Duncan <hugoduncan_at_[hidden]> writes:
> 
> > I think I have found a problem with boost/mpl/list.hpp
> >
> > I am including files using BOOST_PP_ITERATE.  One of the files
> > that I include happens itself to include boost/mpl/list.hpp.
> 
> Normally you shouldn't be making general #includes inside a vertical
> iteration loop.  Why don't you just hoist the include of
> <boost/mpl/list.hpp>?

Maybe my use of ITERATE is slightly different, in that I am using
it to include a LIST of files.  The LIST provides a single
integration point.  Hoisting all the includes reduces the utility
of using ITERATE.

I can hoist the include of <boost/mpl/list.hpp> (and have done so
for the moment), but I don't think that I should have to.

The way I look at it, the fact that MPL uses ITERATE in its header files
is an implementation convenience for MPL, and should not be visible
to the user.  But that's just my opinion, and I may have misunderstood
how MPL is using ITERATE, and/or the purpose of ITERATE.

Hugo