Fokker's jpeg gofer code to haskell?

How would I go about converting some gofer code to haskell? The code

i'm interested in is in the paper:

Jeroen Fokker, Functional Specification of the JPEG algorithm, and an

Implementation for Free. In: Programming Paradigms in Graphics,

Proceedings of the Eurographics workshop in Maastricht, the Netherlands,

september 1995. (R.C. Veltkamp and E.H.Blake, eds). Wien, Springer 1995,

pp. 102-120.

and is avaiable at:

http://www.*-*-*.com/

I've made some progress defining undefined utility functions (by pasting

them in from the gofer prelude and lib files), replacing the monad

constructor "result" with "return", and fixing a name clash "lookup"; but

now I'm stuck: something with the ST monad and StFun.

Thanks,

John Atwood