Variations on a Theme

Come up with variations of your favorite toy problems.  The more obfuscated the better.

I'll start with a simple one:

def factorial(n): return reduce(lambda x,y: x*y, range(1,n
+1)) if n > 1 else 1

>>28-29
It's probably Clojure, but you can implement a reader macro like that with ease in CL, just it seems like a waste of valuable macro characters. If I were to use [] for anything, it would probably be a shorthand for#'(lambda (_) ...), but I already have an Emacs key chord for inserting that...