rvalue references

[Andrei Alexandrescu via Digitalmars-d]

On 6/2/15 11:19 AM, Jonathan M Davis wrote:
> On Tuesday, 2 June 2015 at 18:05:20 UTC, Namespace wrote:
>> AFAIK Andrei wanted 'auto ref' as the syntax which accepts both,
>> lvalues and rvalues. That's why I'm asking if the current behaviour
>> for auto ref for templates should change, or not. If not, we have (as
>> you said) two meanings of auto ref, what is not optimal, but not so
>> bad either (IMO).
>> But if I had the choice, I would change it for both, so that both
>> create a temporary variable for rvalues.
>
> Andrei originally wanted auto ref to apply to non-templated functions,
> but Walter misunderstood what he meant and created what we have now -
> which is actually incredibly useful, because it allows you to forward
> the attributes of an argument - in particular, it's ref-ness. So, we
> definitely do _not_ want to lose that.

Yah, auto ref for templates is great. We only need to add auto ref for 
non-templates with the semantics "like ref, except (a) accepts rvalues 
on the caller side, (b) does not allow escaping the ref from the function".

Note that __traits(isRef, param) doesn't work in an auto ref param in a 
non-template function (attempt to use must be a compile-time error).

That's about it.


Andrei