Limitation with current regex API

[Don Clugston]

On 17/01/12 10:40, Jonathan M Davis wrote:
> On Tuesday, January 17, 2012 05:04:39 Timon Gehr wrote:
>> I don't know exactly, since @safe is neither fully specified nor
>> implemented. In my understanding, in @safe code, operations that may
>> lead to memory corruption are forbidden. Pointer - pointer cannot, other
>> kinds of pointer arithmetic may.
>
> Pointer arithmetic is definitely forbidden in @safe, but I'm not sure that that
> forbids pointer - pointer, since it's not dangerous. It's changing a pointer
> via arithmetic which is dangerous.
>
> - Jonathan M Davis

My guess is that safe D is supposed to enforce C pointer semantics.
At least, code which is both @safe and pure must do so.
The semantics are currently enforced in CTFE.

pointer - pointer is undefined behaviour in C, if the pointers come from 
different arrays. It's OK if they are from the same array, which is true 
in this case.