[Template-haskell] Tool to preprocess template haskell definitions?

Hello I remember someone having written a small utility to preprocess a Haskell source file with TH definitions and generate a new file with the TH bits replaced by their resulting slices. If anyone knows the utility or a way to do this pointers would be nice. I am trying to use Haddock to create documentation, but datatypes are created with TH... - Einar Karttunen