Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/prelude/PreludeList/Scanl1.hs
module Prelude where import Scanl scanl1 :: (a -> a -> a) -> [a] -> [a] scanl1 f (x:xs) = scanl f x xs scanl1 f [] = [] --scanl1 f [] = error "PreludeList.scanl1: empty list"