__traits proposal: derive hierachy and current-scope-type or something

[Christopher Wright]

dennis luehring wrote:
> 1. derive-hierachy
> 
> class A
> class B:A
> class C:A
> class D:C
> 
> * derivedClasses - returns the derived classes
> (what about abstract/interface classes?)
> 
> __traits( derivedClasses, "A" ) ==> [ B, C ]
> __traits( derivedClasses, "C" ) ==> [ D ]

// in file a.d
module a;

class A { }
class B : A { }

// set to ["B"]
const string[] a_derived = __traits(derivedClasses, "A");

// in file c.d
module c;
import a;

class C : A { }
// set to ["B"]
const string[] my_a_derived = a.a_derived;


It's a difficult relationship to get meaningfully and consistent.

> * baseClass (the upward version of derivedClasses)
> 
> __traits( baseClass, "D" ) ==> [ C ]
> __traits( baseClass, "B" ) ==> [ A ]

This works reliably.

> should maybe work only in module-scope

For derivedClasses, it'd have to.

> 2. current-scope-type
> 
> class bla
> {
>   scope-type = in class bla
>   void test()
>   {
>     scope-type = in class bla.test()
>   }
> }
> 
> maybe with line/module information

I don't get the purpose of this.

> only at compile-time
> 
> ciao dennis