[<<][haskell][>>][..]Sun Jun 17 02:32:42 EDT 2018

https://www.reddit.com/r/haskell/comments/4fkkzo/when_does_one_consider_using_arrows/ Come up with some other examples? A function and its inverse? data InvFun a b = InvFun (a->b) (b->a) https://hackage.haskell.org/package/invertible Not an arrow, because "arr" doesn't have an implementation. Kmett: Arrow is primarily used when one has failed to discover Applicative. One of the primary motivations for them was to find a way to model Swiestra and Duponcheel's parser for LL(1) grammars... which actually makes a much better Applicative than an Arrow. The main usecase I have for importing Control.Arrow these days is when I want to call (&&&), not to define instances. EDIT 7/21: Kmett: class (Strong p, Category p) => Arrow p instance (Strong p, Category p) => Arrow p See 7/21

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