D 2015/2016 Vision?

[Namespace via Digitalmars-d]

On Wednesday, 7 October 2015 at 11:27:49 UTC, Marc Schütz wrote:
> On Wednesday, 7 October 2015 at 10:03:44 UTC, Namespace wrote:
>> Because there is no guarantee that others, who use your code, 
>> get it right and use those constructs.
>
> The obvious way would be to make the constructor private and 
> only provide a factory method returning a Scoped!Texture2D. I 
> just tried that, but ran into problems with the construction 
> (probably a bug in emplace). Don't have time to investigate 
> this now. Maybe you can also return a Unique!Texture2D, but 
> that one doesn't have an alias this...

Something like this?

----
import std.stdio;

struct Scoped(T) if (is(T == class)) {
     private void[__traits(classInstanceSize, T)] _buf = void;

     this(Args...)(auto ref Args args) {
         _buf = typeid(T).init[];
         this.get().__ctor(args);
     }

     @disable
     this(this);

     ~this() {
         .destroy(this.get());
     }

     @nogc
     private inout(T) get() inout pure nothrow {
         return cast(T) _buf.ptr;
     }

     auto opDispatch(string method, Args...)(auto ref Args args) {
         return mixin("this.get()." ~ method ~ "(args)");
     }
}

class A {
     private string name;

     private this(string name) {
        this.name = name;
        writeln("Creating A");
     }
	
	static auto scoped(Args...)(auto ref Args args) {
		return Scoped!(typeof(this))(args);
	}

     ~this() {
        writeln("Destroying A");
     }

     void hello() {
        writeln("Hello, ", this.name);
     }
}

void main() {
	auto a = A.scoped("Foo");
	a.hello();
}
----

Kinda ugly, but it works.