AMDG On 9/28/2010 10:53 AM, David Abrahams wrote:
The problem is that concepts force all checks into this realm. I don't know what you're getting at, but it might be related to this:
At Tue, 28 Sep 2010 10:12:29 -0700, Steven Watanabe wrote: the fact that concepts do early checking is problematic for many of our current TMP idioms, which rely on having checks only at instantiation time. For example, foo<mpl::_1> couldn't be written if foo were a constrained template, unless mpl::_1 just happened to satisfy its requirements.
This isn't really what I mean. I personally avoid using placeholders anyway, as I've had bad experiences with unexpected instantiations.
Anyway, yeah, that's a clash. But maybe in a "concepts" world we wouldn't want to do that in the first place.
I'm obviously failing to communicate, so I'll try to come up with a more concrete example. In Christ, Steven Watanabe