"Paul Mensonides" <[EMAIL PROTECTED]> writes: > ----- Original Message ----- > From: "David Abrahams" <[EMAIL PROTECTED]> > >> I tend to agree on a "moral/aesthetic" level, but on a practical level >> we have to tread carefully. The question, "can we just have an >> operator which produces a compile-time constant value saying whether >> its operand is a valid expression?" has come up a few times in the >> committee. Each time, the implementors looked at their codebases and >> said "oooh, that's really hard to do." I think the short form of the >> reason is that C++ compilers generally don't have the ability to >> recover from errors reliably. That may explain why your 2nd, 3rd, >> 4th... diagnostic messages tend to be useless gibberish ;-) >> >> So, I'd like to push for something like that but practically speaking >> I'm not sure how to get there. > > The problems are not insurmountable though (with an "is_valid_expression"). > You aren't dealing with entire language at this point, only an > expression.
And which parts of the language does that fail to drag in? Not many. Actually, not that it matters, but I think I'm misquoting the original request, which was, IIRC, "tell us whether evaluating this expression should produce a compilation error." Howard knows for sure... -- David Abrahams [EMAIL PROTECTED] * http://www.boost-consulting.com Boost support, enhancements, training, and commercial distribution _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost