DIP33: A standard exception hierarchy

[Lars T. Kyllingstad]

On Wednesday, 3 April 2013 at 08:40:52 UTC, deadalnix wrote:
> On Tuesday, 2 April 2013 at 20:11:31 UTC, Lars T. Kyllingstad 
> wrote:
>> Phobos/druntime devs can always add to the enums.  Users still 
>> have the option of subclassing if strictly necessary.
>>
>
> This is fundamentally incompatible with :
>
>> I'm not sure I agree with that rule.  And anyway, D's final 
>> switch mitigate some of the problems with classic switch.
>>
>
> As adding an entry unto the enum will break every single final 
> switch in user code.

I don't see the incompatibility.  This is exactly the purpose of 
final switch.  If the user didn't want to be forced to handle a 
new error category, they'd use normal switch instead.

You have yet to specify the problems with switch in OOP.  Maybe 
you meant something else, that final switch doesn't solve?

Lars