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Editorial Team
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Asked: 2026-05-19T05:15:03+00:00

The Scala collections api has some pretty interesting properties and I’m wondering how one

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The Scala collections api has some pretty interesting properties and I’m wondering how one would implement it in Haskell; or if it’s even possible (or a good idea in general). I’m a bit of a haskell newbie so I’d like to hear your thoughts.

The scala map definition looks like this:

def map[B, That](f: A => B)(implicit bf: CanBuildFrom[Repr, B, That]): That

An interesting feature of this API is that if you map over a string and your map function returns a character, the result will be of type string (and not a list of characters).

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  1. Editorial Team

    We have something roughly as general as the Scala API. It’s called Foldable.

    class Foldable t where
  fold :: Monoid m => t m -> m
  foldMap :: Monoid m => (a -> m) -> t a -> m
  foldr :: (a -> b -> b) -> b -> t a -> b
  foldl :: (a -> b -> a) -> a -> t b -> a
  foldr1 :: (a -> a -> a) -> t a -> a
  foldl1 :: (a -> a -> a) -> t a -> a

    http://www.haskell.org/ghc/docs/6.12.2/html/libraries/base-4.2.0.1/Data-Foldable.html

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