Re: [boost] Named template parameters

From: David Abrahams (abrahams_at_[hidden])
Date: 2001-03-05 17:57:54

I'm not fond of this proposal, because it forces people into long-winded
usage. Also, iterator_traits<Base> are seldom going to be correct, are they?
Maybe it's too tricky, but I'm sure with enough metaprogramming you could
get it to detect whether any of the /currently existing/ parameters are
built traits using the named parameters technique, and begin extracting
trait values from there.

My point is that people who just want to target conforming compilers ought
to be able to work with the current (terse) usage... and I guess this also
argues for moving the Pointer parameter to the back again, once we also have
your new technique.

What do you think of that?
-D
----- Original Message -----
From: "Jeremy Siek" <jsiek_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Monday, March 05, 2001 5:00 PM
Subject: Re: [boost] Named template parameters

>
> So this is what iterator traits would look like:
>
> template <class Base, class Policies,
>   class Traits = boost::detail::iterator_traits<Base> >
> struct iterator_adaptor;
>
> Then the iterator_traits_builder could be used (or not) for the Traits
> argument.
>
> So you could leave off the Traits completely if the default is OK. Is this
> what you mean by the terse usage?
>
> I suppose the rest of the generators would switch back to taking a traits
> class instead of the individual types.
>
> Cheers,
> Jeremy
>
> On Mon, 5 Mar 2001, David Abrahams wrote:
>
> abraha>
> abraha> ----- Original Message -----
> abraha> From: "Jeremy Siek" <jsiek_at_[hidden]>
> abraha> To: <boost_at_[hidden]>
> abraha> Sent: Monday, March 05, 2001 4:03 PM
> abraha> Subject: Re: [boost] Named template parameters
> abraha>
> abraha>
> abraha> > On Mon, 5 Mar 2001, David Abrahams wrote:
> abraha> > abraha> Likewise; I don't have a preference... Alexy's got a
point here,
> abraha> and since
> abraha> > abraha> he's an originator of the technique, maybe we should
defer to him.
> abraha> >
> abraha> > Sure. Shall I go ahead and dive in to changing
iterator_adaptors.hpp?
> abraha>
> abraha> If you've figured out how to preserve the non-named
> abraha> (terse) usage, then OK.
> abraha>
> abraha>
> abraha>
> abraha>
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> abraha>
> abraha>
> abraha>
>
> ----------------------------------------------------------------------
>  Jeremy Siek                        www: http://www.lsc.nd.edu/~jsiek/
>  Ph.D. Candidate                  email: jsiek_at_[hidden]
>  Univ. of Notre Dame         work phone: [phone]
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