haskell - What is a monad? - Stack Overflow
网页2008年9月5日 · A monad is, effectively, a form of "type operator". It will do three things. First it will "wrap" (or otherwise convert) a value of one type into another type (typically called a "monadic type"). Secondly it will make all the operations (or functions) available on the underlying type available on the monadic type.
functional programming - Monad in plain English? (For the OOP ...
网页2010年4月24日 · Monads allow ordered computation within Functional Programing, that allows us to model sequencing of actions in a nice structured form, somewhat like a DSL. And the greatest power comes with the ability to compose monads that serve different purposes, into extensible abstractions within an application.
haskell - A monad is just a monoid in the category of endofunctors ...
网页2010年10月6日 · Going to Chapter VII on Monoids (which comes later than Chapter VI on Monads), we find the definition of the so-called strict monoidal category as triple (B, *, e), where B is a category, *: B x B-> B a bifunctor (functor with respect to each component with other component fixed) and e is a unit object in B, satisfying the associativity and ...
c# 3.0 - In C#, What is a monad? - Stack Overflow
网页A monad is some way to do this "combining of computations". Usually your most basic "operator" to combine two computations together is ;: a; b. When you say this you mean "first do a, then do b ". The result a; b is basically again a computation that can be combined together with more stuff.
What is the difference between a Functor and a Monad?
网页2017年7月22日 · Functors and monads both provide some tool to wrapped input, returning a wrapped output. Functor = unit + map (i.e. the tool) where, unit = something which takes raw input and wraps it inside a small context. map = the tool which takes a function as input, applies it to raw value in wrapper, and returns wrapped result.
Why monads? How does it resolve side-effects? - Stack Overflow
网页Producing a value without effect (return) In order to fill the missing bits in our promptBoolean function, we need a way to represent dummy actions without any side effect but which only outputs a given value: -- "return 5" is an action which does nothing but outputs 5. return :: (Monad m) => a -> m a.
Compose nested Monads in Haskell - Stack Overflow
网页2015年10月17日 · Expanding on the comments: As the linked questions show, it is necessary to have some function n (m a) -> m (n a) to even have a chance to make the composition a monad. If your inner monad is a Traversable, then sequence provides such a function, and the following will have the right type: (>>>=) :: (Monad m, Monad n, Traversable n) => m (n a ...
haskell - Why do we need monads? - Stack Overflow
网页2015年1月25日 · This example illustrates, that monads not only allow you to abstract computational context and write clean reusable code (due to the composability of monads, as @Carl explains), but also to treat user-defined datatypes and built-in primitives uniformly. This answer explains, why we need the Monad typeclass.
Monads in JavaScript - Stack Overflow
网页So I want to understand the practical cases where monads in JavaScript are helpful. I read a bunch on articles on Monads in JavaScript and understand that jQuery is one example of its use. But besides the "chaining" pattern, what other issues can be effectively solved using Monads in front-end engineering? Ref:
haskell - What are free monads? - Stack Overflow
网页2012年11月13日 · Free monads are just a general way of turning functors into monads. That is, given any functor f Free f is a monad. This would not be very useful, except you get a pair of functions. liftFree :: Functor f => f a -> Free f a. foldFree :: Functor f => (f r -> r) -> Free f r …