A simplification of the RvalueRef idiom

[Satoshi via Digitalmars-d-learn]

On Tuesday, 22 November 2016 at 19:16:56 UTC, Ali Çehreli wrote:
> On 11/22/2016 08:05 AM, Satoshi wrote:

> I don't have extensive experience with other languages. In 
> fact, the only other languages that I can claim proficiency are 
> C and C++. (I also know Python just enough to find it 
> incredible how it's used in the industry. Let's not get in to 
> that discussion but I really tried and failed... in industry... 
> :) ) Given that experience, I still find D a very useful tool.
>

D is one o the best languages what exists, it's reason why I'm 
using it. But some issues are solved better in other languages 
like rust, go or swift.


> Agreed but it opens the door for bugs. Assuming
>
> struct A { int a; }
> struct B { int b; int c; }
>
> void foo(int, int, int);
>
> If foo(1, 2, 3) meant foo(A(1), B(2, 3)) today, it could 
> silently mean foo(A(1, 2), B(3)) if one moved one member from 
> one struct to the other.
>
> Then there are other corner cases:
>
>     writeln(1, 2, 3);
>
> Should that print the integers or A(1) and B(2, 3)? It's always 
> better to be explicit.
>

argument expand should be applied only to the last argument and 
cannot be used in variadic templates. Like in my simple example 
where I exactly know what function will do, but I want to call it 
by simplest way.

It actually works with classes, but no with structs.


> import std.stdio;
>
> struct Point {
>     int x;
>     int y;
> }
>
> struct GraphicsContext {
>     static GraphicsContext current() {
>         return GraphicsContext();
>     }
>
>     void moveTo(Point point) {
>         writefln("Moving to %s", point);
>     }
>
>     void lineTo(Point point) {
>         writefln("Drawing line to %s", point);
>     }
> }
>
> void goTo(GraphicsContext gc, int x, int y) {
>     gc.moveTo(Point(x, y));
> }
>
> void drawTo(GraphicsContext gc, int x, int y) {
>     gc.lineTo(Point(x, y));
> }
>
> void main() {
>     auto gc = GraphicsContext.current;
>     gc.goTo(70, 70);    // <-- Clean syntax
>     gc.drawTo(70, 170);
> }

But I need to write overload function for every function taking 
simple messengers like Point/Size/Rectangle