I created a bunch of global hashes that contain references to all sorts of hashes, arrays, variables, and subs, which may or may not be defined, depending on whether or not they are needed. Typically (99%+ of the time) I will not use all of the references within any given global hash.

However, many of the places where I created the more localized variables, I have several different hashes which have the same keys, but different values or references. So I use an array to keep track of the keys. It's made that way mostly for readability's sake (I use fairly long and descriptive variable names); I plan to pass this code on to other maintainers after I get done with it.

I really appreciate the tip, though. I was aware of the keys() function, but never really thought about using it :)