Left and Right Folding over an Infinite list

Question

I have issues with the following passage from Learn You A Haskell (Great book imo, not dissing it):

One big difference is that right folds work on i

Answer 1

Your understanding is correct. I wonder if the author is trying to talk about Haskell's lazy evaluation system (in which you can pass an infinite list to various functions not including fold, and it will only evaluate however much is needed to return the answer). but I agree with you that the author isn't doing a good job describing anything in that paragraph, and what it says is wrong.