About ref used for performance reasons with struct

[kinke]

On Tuesday, 12 February 2013 at 15:53:57 UTC, Namespace wrote:
> Don't get me wrong, I also hope that this unfortunate and 
> lengthy discussion ends. And I also like the idea that const 
> ref works as in C++.
> But I'm sure you can convince neither Walter nor Andrei still 
> the core developer team.

I tried my best a while back, but they sadly didn't take part in 
the discussion. Just in case, it's summarized in 
http://forum.dlang.org/thread/zteryxwxyngvyqvukqkm@forum.dlang.org.
I could live with 'const auto ref' too, but I'd hate having to 
type these 5 additional characters every time. ;)

> And I don't quite understand what speaks against my suggestion.
> If the compiler decides that by value is a better solution, 
> then structs are received by value, otherwise by ref. But the 
> user don't need to worry about it, because, whatever the 
> compiler may decide to do, he adapt calls to these functions 
> automatically.

Your proposal, if I understood correctly, restricts deadalnix' 
approach to rvalues only and additionally requires changing the 
param from 'A' to 'A&'. But iirc rvalues are already passed 
directly (moved) in D, i.e., they are not copied - so your 
approach is 1) simply not needed and 2) would require the A -> 
'A&' transform (similar to A -> 'auto ref A').

> It is in principle nothing more than what you want.

No, nothing more, but it's already covered by D, without special 
syntax. I'd like to see
1) the move optimization applied to safe lvalue cases as well, 
also without requiring syntactic changes;
2) Kenji's 'auto ref' proposal getting pulled in the near future 
so that we can manually prevent argument copying for the 
remaining unsafe lvalue cases.