Having trouble with parallel Haskell

[Isaac Dupree]

Bryan O'Sullivan wrote:
>   | otherwise = rnf lesser `par` (rnf greater `pseq`
>                 lesser ++ x:greater)

It seems that `pseq` doesn't have a defined precedence, so it's infixl 
9, unlike `seq` and `par` which are infixr 0.  Therefore the above is 
equivalent to

   | otherwise = rnf lesser `par` ((rnf greater `pseq` lesser)
                 ++ x:greater)

(no idea if that's relevant, though)

-Isaac