Jaakko Jarvi <jajarvi@cs.indiana.edu> writes:
On May 5, 2004, at 1:26 PM, David Abrahams wrote:
Jaakko Jarvi <jajarvi@cs.indiana.edu> writes:
On May 4, 2004, at 7:56 PM, Fredrik Blomqvist wrote:
I think it would be convenient if one could treat std::pair as a boost two-tuple. Both tuples::tie and tuple assignment already work with std::pair but I've noticed that the get<> accessor doesn't.
So, I propose a simple extension to tuples::get<> with the obvious semantics: boost::get<0>(p) == p.first boost::get<1>(p) == p.second
The trouble with get is that pairs live in namespace std, so if pair get's are not in std, they won't get found by ADL. But if we are willing to live with not having ADL, adding gets for pairs would be fine.
Isn't there another problem? Are references legal arguments for std::pair?
No, they aren't and thus we can't make pairs and 2-tuples have equivalent behavior in all cases. However, it seems that adding the get functions for pairs would not be problematic in this sense.
OTOH, what Thorsten suggested, that 2-tuples would inherit from pairs, would not work.
tuple<int&,char> could be derived from pair<reference_wrapper<int>,char>, no? -- Dave Abrahams Boost Consulting http://www.boost-consulting.com