Re: [Haskell-cafe] defining last using foldr

For a really good article to see how foldr is in fact very powerful and how you can make it do some funny tricks, see the Monad.Reader 6th issue : http://www.haskell.org/sitewiki/images/1/14/TMR-Issue6.pdf I'll point out that you can write a lazy dropWhile with foldr in the style of the first example of the article just by using a non-refutable pattern in the combine function : dWLazy p = snd . foldr (\a ~(x, y) -> if p a then (a : x, y) else (a : x, a : x)) ([], []) -- Jedaï