[namelosw]

I think it's hard to do just side-by-side comparison. Just imagine you just go back to 90s and convince C++ fans using Java.

They are all general purpose programming languages, just with some better/different design decisions to make things safer or relatively more/less expressive.

Similarly, the difficulty to explain Monad is Monad itself is pretty abstract and general. You can describe what it is, but it's hard to guarantee what the audience get from you. Someone says it can solve asynchronous programming issues, then someone will think it's something just for solving this kind of issues. Same as solving null pointer exceptions. After all, it's an abstract representation of sequencing computations with effectful context. But the last one is much harder to understand than the formers.

An equivalent thing is expressing the concept of the "variable" to a mathematical audience who never heard of a computer. They can definitely understand part of it, but not what you want to express.

[PaulAJ]

The "Monad" typeclass in Haskell is a unification of a bunch of things that are treated separately in other programming languages. By "unification" I mean the same kind of thing that physicists mean when they say that Maxwell unified light and electrical phenomena, or that Newton unified physics and astronomy.

It is this unification that makes monads so powerful; one abstraction handles sequencing, exceptions, non-determinism, parsing, IO, transactions, asynchronous state machines and tons of other stuff.

[chii]

i like to explain monads as the same sort of thinking process as a 'design pattern' in OOP. People who have done OOP would have heard of things like the visitor pattern. In OOP, patterns aren't unified in some class, but could be.

Monads (and type classes in general) are like design patterns in OOP, in that they encode a common use case. Except in haskall, you can encode this pattern into the language semantics.

[james_s_tayler]

>Similarly, the difficulty to explain Monad is Monad itself is pretty abstract and general.

A Monad is just a Monoid in the Category of Endofunctors.

[PaulAJ]

For the non-Haskell readers, I should point out that this is just an old joke in the Haskell community. If you want it explained, see here:https://stackoverflow.com/questions/3870088/a-monad-is-just-...

[james_s_tayler]

damn... I missed "what's the problem?" haha.

[mikojan]

This. What's so hard to understand about that?

[alexanderdmitri]

Would I be correct in saying you just encapsulated the monad state type `this` in an identity `that` by creating a monad transformer out of `understand`?