[Haskell-cafe] defining last using foldr

Chaddaï Fouché chaddai.fouche at gmail.com
Fri Aug 17 19:23:38 EDT 2007

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 :

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)) ([], [])


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