Re: rvalues -> ref (yup... again!)

[Rubn via Digitalmars-d]

On Monday, 26 March 2018 at 22:48:38 UTC, Walter Bright wrote:

On 3/26/2018 12:24 PM, Manu wrote:

On 26 March 2018 at 07:40, Atila Neves via Digitalmars-d

C++ const T& -> D T

Yeah, no... T may be big. Copying a large thing sucks. Memory copying

is the slowest thing computers can do.

As an API author, exactly as in C++, you will make a judgement on a case-by-case basis on this matter. It may be by-value, it may be by const-ref. It depends on a bunch of things, and they are points for

consideration by the API author, not the user.

Copying does suck, I agree. Consider the following:

    void foo(T t) { foo(t); } <= add this overload
    void foo(ref T t) { ... }
    T aaa();

    foo(aaa());

With inlining, I suspect we can get the compiler to not make any extra copies. It's not that different from NRVO. And as a marvy bonus, no weird semantic problems (as Atila mentioned).

How do you add this overload for the following?


void foo(ref T t) { ... }

void function(ref int) func = &foo;
int aaa();

func(aaa()); // err