Interface file

[Jan Johansson via Digitalmars-d]

Hello all,

I'm testing D language, and the first thing I want to do is to 
separate declaration from implementation. I was happy to find 
support of interfaces in the D language, and set out to do a 
basic test. However, this test failed, and I want some newbie 
help to understand how it should be done in D language.

----------------------

The interface file (I called it test.di):

// Interface
interface IMyTest {
   void Write(string message);
}

// Factory for type implementing IMyTest
IMyTest createInstance();

----------------------

The library file (I called it test.d):

import std.stdio;

class MyTest : IMyTest {
     void Write(string message) {
         writeln(message);
     }
}

IMyTest createInstance() {
     return new MyTest;
}

----------------------

And finally the main file (I called it main.d):

import test;
import std.stdio;

void main() {
     auto p = createInstance();
     p.Write("Hello, World!");
}

----------------------

The assumption was that I could do:

   dmd test.d test.di -lib -oftest

and next do:

   dmd main.d test.di test.a


The shared information is in the test.di file.

However, this failed, since the first statement generates the 
following:

   dmd test.d test.di -lib -oftest
   Error: module test from file test.di conflicts with another 
module test from file test.d

I guess it is because the file name test.d and test.di creates 
conflict, surfaced as module test.

How can I accomplish what I want to do?

Kind regards,
Jan Johansson