safer casts - take II

[BCS]

Reply to terranium,

> BCS Wrote:
> 
>> The proposed dynamic_cast template, can't be implemented safely and
>> efficiently
>> with the primitives you propose.*
>> *You either get a redundant downcast check, invoke the exception
>> handling
>> system or you need to use reinterpret_cast.
>
> this should be deemed as sort of legacy functionality, so it need not
> to be efficient.
> 

As far as I'm concerned it's still an open question if the dynamic_cast or 
force_cast (by whatever name) will be used more often. So I don't see how 
you can call it legacy.