LRU cache for ~=

[Andrei Alexandrescu]

Sean Kelly wrote:
> Andrei Alexandrescu Wrote:
>> 
>> What I'm saying is that with the cache in place we'll have slices
>> that are safe and efficient. Right now they are not safe and not
>> efficient. I can hardly find reasons to characterize the new state
>> of affairs as kludgey.
> 
> I'm not sure I agree that they'd be safe.  Given only a pointer to
> the head of a block there's no way to know whether it represents the
> array or a slice of the array from [0..n].

That's the beauty of the cache: with the cache in place, you may 
actually know that the memory beyond the end of a cached slice is seen 
by nobody else.

Andrei