On 9/22/2010 1:22 AM, Thomas Heller wrote: > Let me add something: > > The more I thought i about the problem, the more i thought that this would > be a perfect use case for sub domains! So i tried to hack something > together:
Interesting thought. <snip> > > This seems to be exactly what Roland wanted to achieve in the first place. > However, it looks like this design just overcomplicates stuff because we > have to specify the "addition" in our base domain anyway ... Yeah, it's rather complicated. Especially considering that lone terminals really are valid in the super-domain, so the grammar of the super-domain should simply reflect that. > Initially i was under the impression that this wasn't needed, but it seems > that proto cannot deduce something like: > > lhs_expression OP rhs_expression results in expression > > So the question is: is it reasonable to add features like that? > It seems valuable to me. Right, there's potentially a problem in Proto here. If RHS and LHS are in different domains, a common super-domain is deduced first, and then Proto checks to see if the LHS and RHS conform to that common domain. That doesn't seem right. Can you open a ticket? > If I omit the addition in the my_domain grammar, I could have defined the > operator== myself. However I think that somehow defeats the purpose of > proto, doesn't it? Yes, you shouldn't have to define your own operators. It's tricky business. -- Eric Niebler BoostPro Computing http://www.boostpro.com _______________________________________________ proto mailing list proto@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/proto
