FWIW, Julia does segment its method tables into multiple layers depending upon size and type. Multiple dispatch is a strict superset of single-dispatch, and indeed the first layer is just a dictionary/hash table lookup on the first argument. If there's only one result there, you're done (and have the same ~cost for the same ~complexity).
Thanks, I didn't know that! Has it always been like that? I wondering where I got the idea that it was always a linear search from? Maybe that is just the conceptual way of explaining it.
