Code fails with linker error. Why?

[eles via Digitalmars-d-learn]

On Monday, 6 October 2014 at 15:44:36 UTC, John Colvin wrote:
> On Monday, 6 October 2014 at 12:36:41 UTC, ketmar via 
> Digitalmars-d-learn wrote:
>> On Mon, 06 Oct 2014 11:54:55 +0000
>> John Colvin via Digitalmars-d-learn 
>> <digitalmars-d-learn at puremagic.com>
>> wrote:
>>
>>> I disagree. It's simple and easy to understand.
>> and hackish.
>
> D is very amenable to slightly hackish code.
>
>>> This is the only genuine problem I can see that requires a 
>>> language extension. Separating class definition from method 
>>> definition in to different compilation units doesn't allow 
>>> access to private members without very nasty hacks.
>
>> no hacks needed.
>
> I meant that without a language change, one does need hacks.

So, you admit it is a hack! Gotcha!