RT/CT Type

[pham]

On Tuesday, 2 April 2019 at 10:45:37 UTC, Jacob Carlborg wrote:
> On 2019-04-02 09:48, Alex wrote:
>> Since D has a highly evolved meta programming and it should 
>> have unitifed type that works two ways:
>> 

>> 
>> This is a contrived example but I'm finding that I'm having to 
>> use CTFE to deal with types which requires strings and then 
>> convert those strings back in to types using string mixins, 
>> which is a PIBA.
>
> 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