What advantage does Monad give us over an Applicative?
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arrowdodger
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Published on 2013-07-01T16:26:15Z
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2013/07/02
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I've read this article, but didn't understand last section.
The author says that Monad gives us context sensitivity, but it's possible to achieve the same result using only an Applicative instance:
let maybeAge = (\futureYear birthYear -> if futureYear < birthYear
then yearDiff birthYear futureYear
else yearDiff futureYear birthYear) <$> (readMay futureYearString) <*> (readMay birthYearString)
It's uglier for sure, but beside that I don't see why we need Monad. Can anyone clear this up for me?
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