Andrei Alexandrescu wrote:
2. I haven't measured, but the cost of the indirect call is large enough to make me suspect that opApply is not as efficient as it's cracked to be, even when compared with an iterator.
When you know the type beforehand or can use templates, that is, rather than wrapping your range struct in a wrapper class. If you can't use a template for whatever reason, ranges are going to suck -- three virtual calls rather than one.
I don't usually care sufficiently about performance to worry about whether a call is virtual or not, but you brought that issue up before. And I imagine that, most of the time, you will know the range type in advance.
