Regarding the hash references..
"Actually I would numify the reference since it's cheaper but that's not the point."

I took this to mean that you would be comparing references (numbers) instead of strings. If you use a hash for a key for remembering what data you have processed, then the key gets stringified, what I wasn't thinking was that the values of the keys wouldn't be stringified and that's what you would be comparing. slaps($self).

As far as taking my word on the diffculties, don't take my word for anything. I don't know enough about internals but I think if it was that easy we would have had it a long time ago. Personally I'd like to see it. Very handy. One of the reasons I am trying to get into internals is to figure out how to implement coroutines and such. Haven't had that much time to devout so far and for me it's taking awhile. So many macros!

-Lee

"To be civilized is to deny one's nature."