> why `m a -> (a -> m b) -> m b` but not something else? it's basically continuation-passing-style (`a -> m b` is the "continuation"), you might as well ask "w

> why `m a -> (a -> m b) -> m b` but not something else? it's basically continuation-passing-style (`a -> m b` is the "continuation"), you might as well ask "why can you represent so many control-flow things using CPS?". idk why, but you can! from another angle, you could compare Monad with the less powerful Applicative. a formulation[0] that's easier to parse than the usual one[1] is: class Functor f => Applicative f where unit :: f () pair :: f a -> f b -> f (a, b) if you're familiar with JS Promises, a rough analogy would be >>= (Monad) Promise.then pair (Applicative) ≈ Promise.all unit (Applicative) = return (Monad) = Promise.resolve ignoring parallelism, you can implement Promise.all using Promise.then, but not the other way around. --- [0] Called "Monoidal" here: https://stackoverflow.com/q/45267953 https://stackoverflow.com/q/45267953 [1] https://en.m.wikibooks.org/wiki/Haskell/Applicative_functors#The_Applicative_class https://en.m.wikibooks.org/wiki/Haskell/Applicative_functors...