Haskell - What is Control.Applicative.Alternative good for?

alternative-functor, applicative, haskell

Solution

It's commonly used with parser combinators. For example, if `space` is a parser combinator that matches a single whitespace character, `many space` would be one that would match consecutive whitespace.

I can agree that it's slightly out of place in `Control.Applicative`, though.

Problem

I was looking at the `Applicative` class within Haskell libraries and stumbled across `Alternative`. What is this class good for? A google search did not reveal anything particularly insightful. And it seems to be completely out of place, bundled as it is with the Applicative package. Could someone please post a possible scenario where you would use this class?

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