[Haskell-cafe] Thompson's Exercise 9.13

[Daniel Fischer]

> so it doesn't work in all cases. The idea is nice, though:
>
> import Data.Maybe
>
> finit  = catMaybes . foldr f [Nothing] . map Just
>   where
>   f x ys = case ys of
>                     [Nothing] -> []
>                     _             -> x:ys
>
> will do fine.
>
Ooooops, only for nonempty lists!