(Cross-posted from haskell-cafe as suggested by Carter Schonwald)

I would love to have foldl' as part of the Prelude. I use it quite frequently and it seems like a beginner trap to have foldl but not foldl' (which is almost always the better choice). I see that foldMap has been added (in addition to all of Monoid and Traversable), why was foldl' left out?

It might be good measure to add foldr' as well, although I use that much less frequently.

-bob