Created
December 13, 2018 03:49
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An implementation of the Either 'rights' function that is slow
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| import Data.Array (snoc) | |
| import Data.Either (Either(..)) | |
| rights :: forall a b. Array (Either a b) -> Array b | |
| rights array = | |
| let | |
| f (Left _) accumulator = accumulator | |
| f (Right value) accumulator = snoc accumulator value | |
| in | |
| foldr f [] array | |
| -- See this gist for the fast implementation | |
| -- https://gist.github.com/gregberns/58c5a5701e545aa757d8a54bf61bebc2 |
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Article on why this is slow.
https://medium.com/@gregberns/purescript-performance-with-foldl-to-get-rights-845118bf87e5