Does D really need something like const&?

[Steven Schveighoffer]

On Fri, 01 Mar 2013 16:16:46 -0500, Namespace <rswhite4 at googlemail.com>  
wrote:

> If your data is massy: use a class. If not and you don't need  
> polymorphism: use a struct. Done! ... or not?

Size is not a major factor when I decide whether to use a struct or  
class.  I don't think the decision for class or struct should be  
inextricably linked to data size.

And I believe, actually, that passing a massive struct by value if it's an  
rvalue IS the most performant -- no copy needed, no referencing needed.

However, I agree we need SOMETHING to avoid writing every function at  
least twice.

I'd also point out that D's notion of rvalue vs. lvalue is too limited,  
and results in unnecessary restrictions.  We may need a marker to tell the  
compiler whether a type is an rvalue or not.  I'd also like to have a way  
to specify a struct member function takes it's 'this' parameter by value.

-Steve