3 ms·
Isn’t it the case that for a given functor (on Set) there can only be at most one Monad structure?
by Jaxan 1y ago
Isn’t it the case that for a given functor (on Set) there can only be at most one Monad structure?
- whateveracct 1y agoNope. It's that there's only one lawful Functor instance. But Applicatives and Monads can be multiple - lists are the classic example (zip vs cross-product)
- Jaxan 1y agoAh right. Didn’t remember it correctly.
- deleted 1y ago[deleted]
- ryandv 1y agoThe cross-product is not to be confused with the Cartesian product, which is related to the (in this case unfortunately named) "cross join" in SQL. Cross products operate in ℝ³, while Cartesian products are just defined over sets. The standard List monad instance uses the latter.
- whateveracct 1y agoah yes my bad! good callout