[Haskell-cafe] Unboxed Rationals?

I have a program which does a lot of computations with Array's of rationals. In order to get better performance I'd like to use unboxed arrays, but, since (Ratio Int) isn't a primitive type this doesn't work. It occured to me that I could rewrite this using -fglasgow-exts where I represent a rational by (# Int, Int #). It isn't too hard to do this, but I'd like to know it it's already in some library out there, so that I can use something already existing. This is a more general problem that I have (I'm pretty new to Haskell) of finding a library to "do X". Victor