Monads are monoids in the category of endofunctors

Re:Monads are monoids in the category of endofunctors by opnitro on Friday September 10, 2021 @12:03PM (#28483449)

To be honest with you, you're right in that you usually get that one without trying. Most of the things we think of as mappable obey the identity rules.

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Re:Monads are monoids in the category of endofunctors by tantalor on Friday September 10, 2021 @12:54PM (#28484225)

I think the confusion is calling anything that doesn't "obey the rules" a map function just because it is named "map".

For example, ruby's hash "map" returns an array instead of hash. That's not really a map, is it?

Making this useless distinction between "things with map function" and "functors" serves no purpose. It should be "things with real/fake map functions".

The name of the function does not matter!

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Re:Monads are monoids in the category of endofunctors by opnitro on Friday September 10, 2021 @11:54PM (#28489308)

Sure, the name doesn't matter. The type does though. `Functor f => a -> b -> f a -> f b` And it most type systems the law can't easily be captured in the type system.

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