I've been playing with AbyssDragon's (A.K.A. SET library the past couple days. I've optimized it a little and made it easier to expand. Check it out at :)

Thanks Nick! Without SET, I would probably never have had the time or patience to work on an expression evaluation library.
double post much? =P
Awesome. SET was one of my favorite things to create (it started as a programming exercise, just to see if I could do it).. I wish I had had the time to maintain it; but I'm glad you were able to!
Great work SD! Oh and great idea to begin with Nick.