bubbleSort xs =
   mapReduce
  (\xs -> head xs)
  (\xs -> tail xs)
  (\xs -> null xs)
  (\xs -> [])
   (bubble)
    xs

Error message


Problem5.hs:33:4:

    Couldn't match expected type `[a] -> [a]'

           against inferred type `[a1]'

    In the fifth argument of `mapReduce', namely `(bubble)'

    In the expression:

        mapReduce

          (\ xs -> head xs)

          (\ xs -> tail xs)

          (\ xs -> null xs)

          (\ xs -> [])

          (bubble)

          xs