[eru]

Yes, I know that `Gen` in QuickCheck is a Monad. What I am saying is `Arbitrary` isn't a Monad.

I know, Arbitrary technically can't be a Monad, because the kinds are wrong. But I mean 'morally': you can fmap the generation process, but you can't fmap the shrinking. Exactly because generation and shrinking are separated; and shrinking is driven purely by the value and type of the generated item, but has no access to any information about the generation process.

> But in general, I would be surprised if such ‘functional’ APIs (map, filter, reduce, bind, etc.) could not be ported to Haskell.

Yes, have a look at the Jack library I already linked to.