On Sep 28, 2006, at 12:13 PM, Andy Little wrote:
"Doug Gregor" <dgregor@cs.indiana.edu> wrote in message
If be "sorting it out myself" you mean implementing decltype and auto in GCC, then "yes"! :)
hmm... (actually that Was a feature request... ;-) ) *Interesting* idea though, trying to hack Gcc.... very foolhardy IMO, unwise, very unwise...
:-)
Sure, but if you don't implement it in GCC... who will?
Am I right that I can add conditional Concept support to headers by :
# ifdef __GXX_CONCEPTS__
... concept stuff
?
Yep.
And what happens if I have for example a Numeric concept (float, int, boost::numeric::interval) and I want to make Integer a 'member'( model?). How would that work? And integer is also a fundamental type of course
That's what concept maps are for, e.g., concept_map Numeric<integer> { }
Would I be able somehow to express that I don't want potentially 'lossy' division. e.g int / int ?
In the concept Numeric (or, perhaps, one of its "refinements", i.e., more specific concepts that inherit/refine "Numeric"), you could write an axiom like: axiom NonlossyDivision(T x, T y) { y == (x / y) * x; } It's a semantic requirement (and, therefore, unchecked); but, users have to at least think about it before lying to you about their division operators.
Anyway I will have to see how well it works in my physical quantities library. I'm glad I finally got round to trying it out :-)
Me too :) Doug