Here is a minimal function for a fold which operates the standard way.
fold : (b -> a -> b) -> b -> List a -> b
fold f =
List.foldl (flip f)
Example use:
fold (++) "" ["a", "b", "c"]
-- result: (("" ++ "a") ++ "b") ++ "c"
-- == "" ++ "a" ++ "b" ++ "c"
-- == "abc"
Additionally, here is a minimal function for a right fold where the call
visually matches how it works.
foldBack : (a -> b -> b) -> List a -> b -> b
foldBack f =
flip (List.foldr f)
Example use:
foldBack (::) ["a", "b", "c"] []
-- result: "a" :: ("b" :: ("c" :: []))
-- == "a" :: "b" :: "c" :: []
-- == ["a", "b", "c"]
--
You received this message because you are subscribed to the Google Groups "Elm
Discuss" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/d/optout.
