implement vs override

[Peter C]

On Monday, 3 November 2025 at 12:29:44 UTC, Quirin Schroll wrote:
>
> ..

Borrowing and idea from Carbon and Rust, you could group all the 
interface methods together in a dedicated block/scope using 
'impl':

It's nice and structured, and would scale very well for handling 
multiple interfaces.

module myModule;
@safe:
private:

import std.stdio : writeln;

interface IWorker
{
     void start();
     void stop();
     int status();
}

class Base
{
     void start()
     {
         writeln("Base: starting generic process");
     }

     void stop()
     {
         writeln("Base: stopping generic process");
     }

     int status()
     {
         return 0; // 0 = idle
     }
}

class Derived : Base, IWorker
{
     // Explicit interface implementation block
     impl(IWorker)
     {
         void start()
         {
             writeln("IWorker: initializing hardware");
         }

         void stop()
         {
             writeln("IWorker: shutting down hardware");
         }

         int status()
         {
             writeln("IWorker: reporting hardware status");
             return 42; // pretend 42 = "active"
         }
     }
}

void main()
{
     auto d = new Derived();

     // Calls Base methods
     d.start();   // "Base: starting generic process"
     d.stop();    // "Base: stopping generic process"
     writeln(d.status()); // 0

     // Calls IWorker methods
     IWorker w = d;
     w.start();   // "IWorker: initializing hardware"
     w.stop();    // "IWorker: shutting down hardware"
     writeln(w.status()); // 42
}