D 2015/2016 Vision?

[bitwise via Digitalmars-d]

On Sunday, 4 October 2015 at 22:10:18 UTC, Namespace wrote:
> On Sunday, 4 October 2015 at 20:18:25 UTC, rsw0x wrote:
>> On Sunday, 4 October 2015 at 18:02:21 UTC, bitwise wrote:
>>> [...]
>>
>> It's just a symptom of D classes being so difficult to use 
>> without the GC, compared to when I first picked up D to now I 
>> find myself barely *ever* using classes and just C-style(er, 
>> D-style?) polymorphism with structs, mixins, and alias this.
>> Bye.
>
> You can use classes without GC _and_ with deteministic lifetime:
>
> ----
> import std.stdio;
>
> class A {
> 	string name;
> 	
> 	this(string name) {
> 		this.name = name;
> 	}
> 	
> 	void hello() {
> 		writeln("Hallo, ", this.name);
> 	}
> }
>
> struct Scoped(T) if (is(T == class)) {
> 	import core.stdc.stdlib : malloc, free;
> 	
> 	enum SIZE = __traits(classInstanceSize, T);
> 	
> 	T obj;
> 	
> 	this(Args...)(auto ref Args args) {
> 		void[] buffer = malloc(SIZE)[0 .. SIZE];
> 		buffer[] = typeid(T).init[];
> 		
> 		this.obj = cast(T) buffer.ptr;
> 		this.obj.__ctor(args);
> 	}
> 	
> 	~this() {
> 		destroy(this.obj);
> 		free(cast(void*) this.obj);
> 	}
> 	
> 	alias obj this;
> }
>
> auto scoped(T, Args...)(auto ref Args args) if (is(T == class)) 
> {
> 	return Scoped!T(args);
> }
>
> void main() {
> 	auto a = scoped!A("Foo");
> 	a.hello();
> }
> ----

And if I want to nest a class in a struct? or pass a class 
around? and still have deterministic destruction?

You can't nest a Scoped in a struct, and RefCounted doesn't work 
on a class.

It just shouldn't be this hard do such trivial things.

    Bit