Re: [boost] traits classes vs. metafunctions

Subject: Re: [boost] traits classes vs. metafunctions
From: Dave Abrahams (dave_at_[hidden])
Date: 2013-03-31 18:49:26

on Sun Mar 31 2013, Stefan Strasser <strasser-AT-uni-bremen.de> wrote:

> I can understand your viewpoint, but even if I wasn't involved in IT
> at the time, and certainly not at that level, I can still say that it
> always seemed rather obvious to me that the "metafunction concept" of
> Boost.MPL is a workaround because of missing native language features
> (using template, class, typedef).
> so I was surprised that it was introduced into the standard when there
> was a chance to natively support metafunctions.

There's a chance to support lots of things natively that nobody has yet
implemented, used, formalized, or proposed.  Invent the mechanism and
put it in a real compiler, and *then* maybe, if it gets used, it will be
time to propose it for standardization.

> that isn't saying that anyone did a bad job when introducing type
> traits, and I'm sorry if it was perceived that way.

I think you're missing the point.  The committee tries hard not to
engage in feature invention, and in the rare cases when it does,
somebody creates an actual implementation of the feature.

-- 
Dave Abrahams