Re: Any way to reproduce Dart style constructors?

[Nicholas Wilson via Digitalmars-d-learn]

On Thursday, 25 May 2017 at 08:34:54 UTC, JN wrote:
One of my favourite language features of Dart (other one being 
factory constructors) are auto-assign constructors, for example 
(writing it in pseudo-D):

class Person
{
  string name;
  int age;
  this(this.age, this.name);
}

would translate to

class Person
{
  string name;
  int age;
  this(int age, string name)
  {
    this.age = age;
    this.name = name;
  }
}


It saves a lot of typing in the long run when doing lots of 
OOP, is there a way to reproduce such behaviour using mixins? I 
was thinking of some interface like:

class Person
{
  string name;
  int age;
  mixin(AutoConstructor!(age, name));
}

but I don't know if that's even doable using mixins. Even 
cooler might be something like an annotation (feels a bit 
Lombok-like from Java):

@AutoConstructor
class Person
{
  string name;
  int age;
}

but I don't think it's doable in D right now.

I am not looking for code, I can try that myself, just asking 
if such things are possible?

Not sure about classes (I don't use them much) but structs have 
an automatically defined constructor. It is most definitely 
possible to do that with a mixin template (I remember someone 
recently showing autogenerating properties for readonly private 
members, sorry don't have a link).

The UDA approach won't work because they are there for 
reflection. You can generate code based on the presence (or 
absence) of a UDA but you can't synthesise new methods with that 
without forwarding from a wrapper.