Shortest Quicksort Ever?

I found this J example on StackOverflow. 43 characters, excluding name, assignment operator, and optional whitespace.

    quicksort =: (($:@(<#[) , (=#[) , $:@(>#[)) ({~ ?@#)) ^: (1<#)

http://stackoverflow.com/questions/2603739/what-is-the-most-...

Usually, when I see an opaque post like this, I'll not worry too much because I figure it's really only relevant to the (very, very, very small) minority of the people who understand it. But it's only 61 characters, and I'm certain that I should be able to walk my understanding of quicksort (refreshed with http://en.wikipedia.org/wiki/Quicksort) - but I'm stumped.

And so, I beging to lose another two hours of my life as I attempt to understand what this interesting syntax mechanism for representing algorithms consists of...

This is a good opportunity to show off the (fake) Haskell quicksort:

qsort :: (Ord a Bool) => [a] -> [a]

qsort [] = []

qsort (x:xs) = qsort (filter (<= x) xs) ++ [x] ++ qsort (filter (> x) xs)

Not 61 characters, but it has the added benefit of being comprehensible!