2009-09-24から1日間の記事一覧
import Maybe (catMaybes) ---Exercise 4.1 safeHead :: [a] -> Maybe a safeTail :: [a] -> Maybe [a] safeLast :: [a] -> Maybe a safeInit :: [a] -> Maybe [a] safeFunc f [] = Nothing safeFunc f xs = Just $ f xs safeHead = safeFunc head safeTail …