When D is not nice

[Frank Benoit]

Simen Kjaeraas schrieb:
> Frank Benoit <keinfarbton at googlemail.com> wrote:
> 
>> String concatenation in Java:
>>
>> "abc " + a + " bla";
>>
>> where a is an interface ref.
>>
>> Ported to D, this look like this:
>>
>> "abc " ~ (cast(Object)a).toString ~ " bla";
>>
>> This are 3 steps more:
>> 1.) explicit cast to Object (interface/class compatibility!)
>> 2.) explicit call to toString
>> 3.) put additional parentheses
>>
>> I would be happy if we could remove all three of this annoying points.
> 
> 
> 
> interface A
> {
>     string opCat(string rhs);
>     string opCat_r(string lhs);
> }
> 
> class B : A
> {
>     string opCat(string rhs)
>     {
>         return toString() ~ rhs;
>     }
> 
>     string opCat_r(string lhs)
>     {
>         return lhs ~ toString();
>     }
> 
>     string toString()
>     {
>         return SomeString;
>     }
> }
> 
> This works for me.
> 
> -- Simen

My intention was not to ask how to solve it for a certain interface.
Instead i was trying to show a flaw in the language design.

Even if i would add object.Object method to /every/ interface, then 
still an interface ref is NOT implicit castable to an Object ref. And i 
would need to reimplement all those methods in every class that 
implements the interface.