On Jul 3, 2012, at 3:13 AM, Eric Niebler wrote:
On 7/2/2012 7:26 PM, Ravi wrote:
On Monday, July 02, 2012 12:41:22 PM Eric Niebler wrote:
Use of a C++11 feature just for the sake of it doesn't seem like such a good idea to me.
<baffle> Have I not given enough good reasons above? Maybe I'll just keep my good ideas to myself next time. :-/
Please don't. This one is actually pretty widely applicable if you are doing type deduction in C++11; it took me quite a while to figure this one out when I ran into it. I, too, fail to see how the reasons you gave were not perfectly clear.
Thanks Ravi. For the record, this trick is also useful for CRTP bases when you need to static_cast this from base to derived in a return type:
Something like this also showed up in Matt Calabrese's suggested BOOST_ENABLE_IF() macro that appeared in this thread: http://lists.boost.org/Archives/boost/2011/08/184465.php I didn't really understand the introduction of the dummy template parameter at the time, and the explanation Matt gave was (rough paraphrase, I can't find the exact quote) The BoostDetailEnableIfDependentType template parameter exists in order to ensure that the later condition is dependent on a template argument. which was pretty opaque to me at the time, but with Eric's explanation I think maybe I now understand.