cats-effect
FS2
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cats-effect | FS2 | |
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34 | 17 | |
1,954 | 2,321 | |
1.7% | 0.9% | |
9.7 | 9.5 | |
5 days ago | 8 days ago | |
Scala | Scala | |
Apache License 2.0 | GNU General Public License v3.0 or later |
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Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
cats-effect
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A question about Http4s new major version
Those benchmarks are using a snapshot version of cats-effect. I don't know where that one comes from, but previously they were using a snapshot from https://github.com/typelevel/cats-effect/pull/3332 which had some issues (3.5-6581dc4, 70% performance degradation), which have since been resolved (see that PR for more info and comparative benchmarks).
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The Great Concurrency Smackdown: ZIO versus JDK by John A. De Goes
Recently, CE3 has had similar issues reported across multiple repositories, almost an epidemic of reports!
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40x Faster! We rewrote our project with Rust!
The one advantage Rust has over Scala is that it detects data races at compile time, and that's a big time saver if you use low level thread synchronization. However, if you write pure FP code with ZIO or Cats Effect that's basically a non-issue anyway.
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Sequential application of a constructor?
See also cats-effect and fs2. cats-effect gives you your IO Monad (and IOApp to run it with on supported platforms). fs2 is the ecosystem’s streaming library, which is much more pervasive in functional Scala than in Haskell. For example, http4s and Doobie are both based on fs2.
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Should I Move From PHP to Node/Express?
On the contrary, switching to the functional mindset, with something like Typelevel Scala3 and respective cats and cats-effect fs2 frameworks, helps to rethink a lot of designs and development approaches.
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Next Steps for Rust in the Kernel
I think "better Haskell on JVM" (in contrast to "worse Haskell") is a good identity for Scala to have. (Please note that this is an intentional hyperbole.)
Of course, there are areas where Haskell is stronger than Scala (hint: modularity, crucial for good Software Engineering, is not one of them). And Scala has its own way of doing things, so just imitating Haskell won't work well.
Examples of this "better Haskell" are https://typelevel.org/cats-effect/ and https://zio.dev/ .
All together, Scala may be a better choice for you if you want to do Pure Functional Programming. And is definitely less risky (runs on JVM, Java libraries interop, IntelliJ, easy debugging, etc...).
None of the other languages you mentioned are viable in this sense (if also you want a powerful type system, which rules out Clojure).
I agree that Rust's identity is pretty clear: a modern language for use cases where only C or C++ could have been used before.
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Java 19 Is Out
I would use Scala. I like FP and Scala comes with some awesome libraries for concurrent/async programming like Cats Effect or ZIO. Good choice for creating modern style micro-services to be run in the cloud (or even macro-services, Scala has a powerful module system, so it's made to handle large codebases).
https://typelevel.org/cats-effect/
https://zio.dev/
The language, the community and customs are great. You don't have to worry about nulls, things are immutable by default, domain modelling with ADTs and patter matching is pure joy.
The tooling available is from good to great and Scala is big enough that there are good libraries for typical if not vast majority of stuff and Java libs as a reliable fallback.
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Typelevel Native
What took my interest is this (for both JVM and future multithreaded Scala native): https://github.com/typelevel/cats-effect/discussions/3070 Having the same threads poll available IO events and execute callbacks should improve performance greatly
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Scala isn't fun anymore
The author is the creator of Monix and implemented the first version of cats-effect. He knows what he is doing.
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Question about some advanced types
You want Kernmantle, which quite honestly shouldn't be hard to implement around Cats and cats-effect. In particular, although Kernmantle doesn't require the use of the Arrow typeclass, there happen to be Arrow (actually ArrowChoice) instances for both Function1 from the standard library and Kleisli from Cats itself, given a Monad instance for the Kleilsi's F[_] type parameter. In other words, we should be able to port Kernmantle from Haskell to Scala (with the Typelevel ecosystem) and instantly be able to use pretty much anything else from the Typelevel ecosystem, or wrapped with it, in our workflow graphs. Pure functions, monadic functions, applicative functions, GADTs with hand-written interpreters, any of it. I think this would be eminently worth doing.
FS2
- Ask HN: What are some of the most elegant codebases in your favorite language?
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The Great Concurrency Smackdown: ZIO versus JDK by John A. De Goes
Recently, CE3 has had similar issues reported across multiple repositories, almost an epidemic of reports!
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Parallel streaming in Haskell: Part 1 – Fast, efficient, and fun
Thanks for the explanation!
So it's pull based and not push based like most other streams lib.
Does maybe someone know how this compares to FS2 or Iteratees than? (Both are also pull based streaming solutions).
https://fs2.io/#/
https://en.wikipedia.org/wiki/Iteratee
Looks quite similar to me. Is the Scala FS2 lib maybe even a clones of the Haskell solution? Or are they different in important aspects?
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Grasping the concepts and getting them down to earth
Most important/known: * https://http4s.org/ - an HTTP client/server * https://github.com/typelevel/fs2 - streaming * https://github.com/tpolecat/doobie - JDBC
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Should I Move From PHP to Node/Express?
On the contrary, switching to the functional mindset, with something like Typelevel Scala3 and respective cats and cats-effect fs2 frameworks, helps to rethink a lot of designs and development approaches.
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Is Scala a good choice for a data intensive web backend?
fs2 for streaming.
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Is “Functional Programming in Scala” 1st edition still relevant?
Finally, the last chapter has been rewritten to be based on some of the main design ideas from FS2 (https://fs2.io), which I hope will be more approachable than the 1st edition.
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FS2 stream doesn't work as I expect it to
Just to clarify, is your doubt about the meaning of the api, or do you think you have found a bug? In either case, you can also open a Github discussion https://github.com/typelevel/fs2/discussions.
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How to update and access state that needs to be shared across multiple API endpoints with FP?
Another more reactive solution would to use signals, as in FPR sinal network. fs2 implements this very nicely here https://github.com/typelevel/fs2/blob/8b285a6b54c63d43ed6aa3bb91365652035c90e5/core/shared/src/main/scala/fs2/concurrent/Signal.scala
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Introducing effects systems S.A. ZIO at work?
Assuming the bug mentioned here is https://github.com/typelevel/fs2/issues/2568, we came up with a partial fix in a day (https://github.com/typelevel/fs2/pull/2569) and a complete fix in 2 days: https://github.com/typelevel/fs2/pull/2572. Note the original bug was opened on a Saturday. :)
What are some alternatives?
ZIO - ZIO — A type-safe, composable library for async and concurrent programming in Scala
Diffy
fs2-grpc - gRPC implementation for FS2/cats-effect
Http4s - A minimal, idiomatic Scala interface for HTTP
doobie-quill - Integration between Doobie and Quill libraries
ScalaMock - Native Scala mocking framework
Kategory - Λrrow - Functional companion to Kotlin's Standard Library
ScalaTest - A testing tool for Scala and Java developers
Slick - Slick (Scala Language Integrated Connection Kit) is a modern database query and access library for Scala
ScalaMeter - Microbenchmarking and performance regression testing framework for the JVM platform.
cats - Lightweight, modular, and extensible library for functional programming.
Gatling - Modern Load Testing as Code