Can we get rid of opApply?

[Steven Schveighoffer]

"Robert Fraser" wrote
> Steven Schveighoffer wrote:
>> The other possibly sensible reason to keep opApply is for 
>> interfaces/classes.  Ranges as a class would be slower than even opApply, 
>> as each loop iteration would call a virtual function.
>
> There would only need to be one vtable lookup for each function (since 
> every iteration would use the same head(), next(), etc.) So it would be 
> the same price as opApply (a function pointer call). Well, 3 times the 
> price, since 3 functions need to be called.

You could technically cache the vtable lookup, but a vtable call costs more 
than a delegate call (one lookup for vtable, then function + pointer call 
vs. just function + pointer call).  But besides that, yes, it would be 3 
functions called per iteration.  So still slower...

-Steve