[Sharlin]

There is a saying that the difference between poetry and math is that poetry is about giving different names to the same thing, and math is about giving the same name to different things.

Grokking monads really requires the adoption of the mathematical mindset of finding commonalities in things that at a first glance appear completely different. Tell an average OO programmer that lists, exceptions, dependency injection, and asynchronous execution all share a common structure, and they will probably give you a blank stare.

Of course, just the fact that abstracting over those things is possible doesn’t mean it is useful. In a pure FP language it might be necessary, but why should I bother with weird mathy things in my imperative language that has side effects and global state? You really have to start by explaining why composability is such a nice thing to have, and that gives the motivation for various FP patterns that are, fundamentally, all about composability.

[eli_gottlieb]

>Of course, just the fact that abstracting over those things is possible doesn’t mean it is useful. In a pure FP language it might be necessary, but why should I bother with weird mathy things in my imperative language that has side effects and global state? You really have to start by explaining why composability is such a nice thing to have, and that gives the motivation for various FP patterns that are, fundamentally, all about composability.

But then you start running into the nasty issue that when you need to compose multiple monads, you find out that monad transformers don't always commute!

[Sharlin]

Yeah. And then you start hearing about these things called algebraic effects…

[dorgo]

>but why should I bother with weird mathy things in my imperative language that has side effects and global state

There are good reasons, like encapsulation, etc. But the real reason is, it just dosn't feel right and there is this urge to fix it.

[tsss]

Because in your imperative language monads can still be a useful abstraction. For example they can give you stuff like async-await or null-safe method chaining for free.

[Sharlin]

Which is exactly my point about composability.