RT/CT Type

[Bastiaan Veelo]

On Tuesday, 2 April 2019 at 17:00:41 UTC, pham wrote:
> On Tuesday, 2 April 2019 at 10:45:37 UTC, Jacob Carlborg wrote:
>> I would much rather that D had first class types. That is, it 
>> would be possible to store types in variables and in arrays 
>> and so on.
>
> Delphi has implemented class type for a long time. D should 
> have vision to implement it. However, D also needs to implement 
> inherited constructor in order for it to work
>
> Skeleton sample in Delphi
>
> type
> A = class
>   create() virtual  // constructor
>     writeln('A.create')
>
> B = class(A)
>   create() override // constructor
>     //inherited create() // call inherited constructor 
> implement if needed
>     writeln('B.create')
>
> ClassType = class of A; // Any class inherited from A can be 
> used to set to this type
>
>
> ClassType x = A;
> var x1 = x.create()  // output 'A.create'
> x = B
> x1 = x.create()  // output 'B.create'
>
> Cheers
> Pham

Jacob is talking about "first class" types. D does support 
classes just like Delphi does (https://dlang.org/spec/class.html):

----
If no call to constructors via this or super appear in a 
constructor, and the base class has a constructor, a call to 
super() is inserted at the beginning of the constructor.

If there is no constructor for a class, but there is a 
constructor for the base class, a default constructor is 
implicitly generated with the form:

this() { }
----