What is it that Leibniz calls a “Monad”? Monads capable of this are called "vernünftige Seelen" or "Geister" (intelligent souls or spirits, "animae") Now, there is a hierarchy of monads with regard to their apperceptions: From "schlummernden" (slumbering) up to the omniscient monad, the "monas monadum" (monad of monads) – God Somewhere in between are animal and spirit monads
haskell - A monad is just a monoid in the category of endofunctors . . . A Monad f is a fixed endofunctor, not a subset of endofunctors closed under composition A common construction is to use f to generate a monoid by taking the set of all k -fold compositions f^k = f(f( )) of f with itself, including k=0 that corresponds to the identity f^0 = id
How to extract value from monadic action - Stack Overflow (See also my previous thoughts on magicMonadUnwrap :: Monad m => m a -> a) Suppose I tell you I have a value which has the type [Int] Since we know that [] is a monad, this is similar to telling you I have a value which has the type Monad m => m Int So let's suppose you want to get the Int out of that [Int] Well, which Int do you want? The
Relationship between Functor, Applicative Functor, and Monad Changing the definition of Monad at this point, would have broken a lot of existing code (any piece of code that defines a Monad instance) to be worthwhile Breaking backwards-compatibility like that is only worthwhile if there is a large practical benefit to the change
What is the purpose of the state monad? - Stack Overflow The maybe monad for instance can be easily understood, because it deals with a problem that both languages are facing: Computations that might go wrong by not returning a value (null undefined in Javascript) Maybe saves developers from scattering null checks throughout their code In the case of the state monad the situation is a little different