[Haskell-cafe] Library for package preprocessing

Hi all, I'm writing a tool to analyze source code of a package, which uses haskell-src-extra. As copied from hackage, libraries may contain some extra stuff (for example, cpp directives). What is the modern way to preprocess the package (configuring for the environment, running the cpp ecc) to obtain code which is guaranteed to be parsed by haskell-src-extra? Ideally I'd like to leave most of the logic for this part outside of the package. Could you point me towards some libraries doing a similar thing? Best regards