On Monday, 26 March 2018 at 14:40:03 UTC, Atila Neves wrote:
On Friday, 23 March 2018 at 22:01:44 UTC, Manu wrote:
Forked from the x^^y thread...
<snip>
There are too many replies on this thread, addressing all the
comments would take forever and pollute the thread itself. So
forgive me if I say something that was covered already by
someone else.
AFAIK being able to bind rvalues to `ref const(T)`, only makes
sense when calling C++ functions that take `const T&`
(especially since that is common). I have not yet heard any
other use for them. I'd be in favour of allowing it _only_ for
`extern(C++)` functions. Otherwise use `auto ref` or have
overloads for pass-by-value and pass-by-ref.
I too, once a recent immigrant from the lands of C++, used to
keep writing `ref const(T)`. I just pass by value now.
C++ T&& (forwarding reference) -> D auto ref T
C++ T&& (Rvalue reference) -> D T
C++ const T& -> D T
C++ T& -> D ref T
If replacing const T& with T chafes, I understand. I used to
feel that way too. It's _possible_ that would incur a penalty
in copying/moving, but IME the cost is either 0, negligible, or
negative (!).
I'm tearing my remaining stubs of hair out trying to understand
why memory copies (not talking about copy constructors) are
needed when passing an rvalue to a non-ref function:
https://stackoverflow.com/questions/49474685/passing-rvalue-to-non-ref-parameter-why-cant-the-compiler-elide-the-copy
