Real World Haskell Chapter 2
last [] last [1..] Haskellで循環リストみたいなものを作れるのならば.
--lastButOne.hs lastButOne (x:xs) = if length(xs) == 1 then x else lastButOne xs
以下のほうが,関数型ぽいかな?
--lastButOne.hs lastButOne (x:[_]) = x lastButOne (x:xs) = lastButOne xs lastButTwo (x:[_,_]) = x lastButTwo (x:xs) = lastButTwo xs