interop-cats VS cats

If you're using http4s, don't use ZIO. Yes, ZIO has an interop-cats module, so you can do this. But using http4s means you're working in the conceptual framework the Typelevel ecosystem is based on (and what interop-cats does can be characterized as "describe ZIO's implementation in those terms, so the Typelevel ecosystem can make heads or tails of it.") This is essentially all cost and no benefit: you can't avoid understanding the Typelevel ecosystem if you use http4s (at least, no more than you can by using cats-effect), and you don't get any of the value proposition of ZIO (interop-cats gives you Typelevel typeclass instances for the RIO type alias, which means your error channel is rooted in Throwable, and you're faced with the most complex part of the ZIO ecosystem: ZLayer, which the Typelevel ecosystem doesn't use and doesn't need). Finally the ZIO ecosystem is still quite immature, and this brings us to documentation. There is not (yet!) anything comparable to:

These are necessarily oversimplifications. In particular, the ZIO ecosystem offers the relevant instances of cats-effect typeclasses to support use of the ZIO type in the cats-effect ecosystem.

However, ZIO continues to offer cats-effect type classes and I certainly have no doubt cats-effect 3 continues to benefit from John's contributions. Furthermore, I likewise don't doubt the value of the ZIO ecosystem generally, and John's success in building the ZIO community speaks for itself. I personally have chosen to remain closer to the other, let's say "classical," pure FP ecosystems, partially for historical (or, if you prefer, "sunk cost") reasons, but partially because I'm satisfied the value of the Haskell/Typelevel/PureScript/fp-ts/etc. interplay warrants it.

It seems that zio/interop-cats faces a similar issue.

A functional programming library: https://typelevel.org/cats/

Learn something that pays the bill first - nowadays it's Golang/Rust react/typescript. Then you can try some pure fp libs like fp-ts and fp-core.rs, and look through existing scala cats docs. If you'll feel bad about it - that's totally fine and expectable, fp takes a paradigm shift and not that many dev able to shift their brains way of thought due to basic psychological rigidity) (inability to change habits and to modify concepts/attitudes once developed). And that's purely a staffing and management issue - folks hired randoms out of the blue, and called 'em a team.

I'm sorry, but have you ever done functional programming for a real company, like in a functional programming language like Haskell, Scala, or F#? Have you ever used Scala cats or scalaz? Have you ever learned category theory and how to apply its abstractions in software? Listen u/judethedude2106 this person hasn't gone as far down the functional programming rabbit hole as I have. Beyond learning the basics like the difference between pure and impure functions, what are closures, what higher order functions are and the most common ones like .map, .filter, and .flatmap, the immutable collections like immutable linked lists and trees, and what a Monad is and common monads like those used for futures/promises, async programming, and Option (Some or None, which is used instead of null checking), the more advanced functional programming stuff like category theory based abstractions are totally useless for real jobs and is just a giant time suck. Don't waste years on functional programming, spend at most a few months on it and no more.

As a former functional programmer in Scala, please do not go deep into the Category Theory programming. Scala has libraries like this one called "Cats", a cute shortened name for "Category Theory", but code that makes heavy use of these constructs is not understandable to other programmers. Other than using Monads as a design pattern for things like Options (which can be "Some" or "None"), Futures or Promises (which is used for asynchronous programming), and a few other things, please do not make heavy use of category theory constructs in real programming projects that will have other developers working on them. It is a rabbit hole that may be fun but is not super practical. Sure, write pure functions without side effects, but do not use the words "Bimonad", "Invariant Monoidal", and "Semigroup" in your code. The most common, practical application/use of functional programming is basic things like closures, .map, .filter, maybe chaining maps with like a .flatmap or whatever your programming language uses instead of chain or flatmap, and SQL that uses keywords like WHERE which can be represented in code by using a call to .filter. Like the place where these constructs are used most is in data processing like with SQL, ETL (Extract Transform, Load) jobs, Java's MapReduce on Hadoop, Scala's Apache Spark, and other data processing type things. Haskell is not a popular programming language in real world projects for a number of reasons and one of them is the heavy and sometimes impractical use of Category Theory.

At a previous job of mine we actually had an entirely pure Scala ecosystem using cats which instead uses typeclasses, referential transparency, and other FP concepts as the foundations for how to code. So a lot of flexibility to the language.

Thanks! It's used heavily here

I did work in Scala for a few years. We employed Cats[1], and even a bit of Matryoshka[2] though most of the work I do today is in Python.

Nowadays I think about computational requirements in terms of relations among behavioral dependencies. Like, "I want to perform operation O on input A and return a B. To do this, I'll need a way to a -> b and a way to b -> b -> b." I often pass these behavioral dependencies in as arguments and it tends to make the inner core of my programs pretty abstract and built up as layers of specificity.

Zooming out nearly all the way, it makes me feel tethered in a qualitatively unique way to certain deep truths of the universe. In a Platonic sense, invoking certain ideas like a monad make me feel like I'm approaching the divine or at least one instantiation of a timeless universal that operates outside of material existence.

I'd imagine some mathematicians might see the universe in a similar way - one where immortal relations between ontological forms exist beyond time and space and at the same time can be threaded through the material world by intellectual observation and when those two meet a beautiful collision occurs.

1. https://typelevel.org/cats/

2. https://github.com/precog/matryoshka

Our second type class example attempted to illustrate one last perk: type safety at compile time. It did so with a simplified example of the cats core library for type safety equality comparison between objects. If you're not familiar with cats, go ahead and give it go.