I am a Haskell newbie. I have coded a Regular Expression to Determinate Finite Automata translator. Algorithm from the Dragon Book.

Would someone eyeball the code and give me suggestions please. 

I have not done anything on character classes yet though. And the parsing is a bit of a hack.

What I am not sure about is having to have multiple versions of similar datatype, each with variations in order to enumerate and generate followPos set.

Is there a better way of implementing this ?

Many thanks in advance,

Aaron