This is a very pretty solution, thanks ! I'm not sure by how much it will improve performance, but a closure fits here well. It's nice that Perl has this ability (borrowed from Lisp, of course) as in some case it may solve a problem graciously, but so can an object. That is said by me, who adores Lisp and FP in general and looks at OO with suspicion, as a nice solution in *some* cases, but surely not the uber-panacea hyped about so much.