foldls

$ ghci
GHCi, version 8.0.1: http://www.haskell.org/ghc/  :? for help
Prelude> :t foldl
foldl :: Foldable t => (b -> a -> b) -> b -> t a -> b

$ elm repl
---- elm-repl 0.17.1 -----------------------------------------------------------
 :help for help, :exit to exit, more at <https://github.com/elm-lang/elm-repl>
--------------------------------------------------------------------------------
> List.foldl
<function> : (a -> b -> b) -> b -> List a -> b