On Monday, March 20, 2017 21:37:26 Yuxuan Shui via Digitalmars-d wrote: > On Monday, 20 March 2017 at 21:34:14 UTC, Yuxuan Shui wrote: > > On Monday, 20 March 2017 at 21:08:40 UTC, Jonathan M Davis > > > > wrote: > >> [...] > > > > This is a bit tedious because it requires you creating a new > > function. > > > > Maybe we can create a template for that. But still, auto ref > > requires us to do things differently, which is annoying. > > Easy solution: just support auto ref for non-templates. > > I think someone has already did work on that?
auto ref for non-templates would not be quite the same thing, and regardless, it wouldn't help any with explictly instantiating a template that had an auto ref parameter. So, it really wouldn't solve the problem at all. It would just make it so that if you didn't want a templated function, you could use auto ref. But for auto ref to work with non-templated functions, it would either result in creating a combinatorial explosion of functions rather than just a single function (basically doing what auto ref does but explicitly instantiating it with every combination of refness instead of just the ones that are actually used), or it would just create a version where every auto ref parameter was ref and silently copy rvalues to the stack to pass by ref when they're passed to the function. I think that there was a PR on the issue at one point, and IIRC, the ultimate decision was to reject it and keep the status quo, because there were too many downsides it (e.g. IIRC, there were problems with overriding functions in derived classes). I think that there was some talk semi-recently about creating a proposal for something similar to C++'s const & but which was more restrictive in order to avoid the downsides with C++'s solution, in which case we might end up with something like @rvalue ref which accepted rvalues - probably by copying them to the stack first. But I don't think that anything has been formally proposed yet. If that goes anywhere, it will probably be the closest that you'll ever get to having auto ref with non-templated functions. - Jonathan M Davis
