Re: Implementing interfaces using alias this

[basile b. via Digitalmars-d-learn]

On Wednesday, 14 June 2017 at 09:34:27 UTC, Balagopal Komarath 
wrote:
Why doesn't this work? The Test!Duck type has a void quack() 
method but the compiler says it is not implemented.

import std.stdio;
interface IDuck
{
    void quack();
}

class Test(T) : IDuck
{
    T data;
    alias data this;
}

struct Duck
{
    void quack()
    {
        writeln("Quack");
    }
}


void main()
{
        Test!Duck d;
}

The way to do that in D is with mixins:

interface IDuck
{
    void quack();
}

class Test(alias MyImpl) : IDuck
{
    mixin MyImpl;
}

mixin template DuckImpl()
{
    void quack()
    {
        import std.stdio;
        writeln("Quack Quack");
    }
}

void main()
{
    (new Test!DuckImpl).quack;
}