Typelevel Scala and the future of the Scala ecosystem (2014)
typelevel.org
typelevel.org
One example I can think of is the Typelevel "Kind Projector" which had a syntax for lambda types. This became an integrated feature of Scala 3
https://github.com/typelevel/kind-projector
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While we're on the frontpage, might as well use this as a small promotion for Scala 3:
I'm predominantly a Typescript developer, though have written (either for money, or for personal projects) a good number of languages.
I passed up Scala 2 several years ago because it seemed overly complicated. And the (perceived/community-driven) emphasis on purely functional programming. I believe in immutability, and love higher-order functions as much as the next fellow -- but only insomuch as they make writing programs easier, and the code simpler/more understandable.
When Scala 3 was announced I went and had a look through the documentation and entry book/guide again.
What I saw was a language that was (for the most part) very intuitive. It has all the features you could ask for, and the language is flexible enough to get out of your way.
You can just as easily write OO or FP code, in a clear/concise/simple manner. I was able to take code that I would have written in Typescript, and transcribe it mostly 1-to-1 to Scala 3, with the bonus of having pattern matching and proper "Maybe" types built in.
Then come some other things that you DON'T get in languages outside of Scala. Contextual values ("given"/"using") blew my mind and are so fantastic + useful.
If you're someone who generally just wants to write pragmatic code and had previously passed on Scala due to reputation, I would encourage checking out the docs and playing with it for an hour to see if it meshes with you.
(Fair warning: most pure Scala libraries have heavy FP patterns, but I've mostly stuck to popular Java libraries and experience has been solid doing this so far)
Had never really used the JVM prior to this. I enjoyed Scala 3 the most out of all of them. Though of course the tooling is not up to par with Java (not much is), that's kind of the tradeoff you make.
Also, F# is really nice I think. Though again same sort of tooling situation when comparing Scala to Java.
This is because it's so easy and natural to use Java libraries from Scala, if you aren't trying to write in a pure FP style. Sharing libraries with the larger Java ecosystem means you get APIs that don't take advantage of Scala features, but it has a lot of advantages, too, and this is what most Scala programmers do if they aren't fully committed to functional programming.
Doing pure FP and managing side effects through effects requires wrapping or replacing Java libraries with pure, effectful APIs, and that is the raison d'etre of a lot of Scala libraries. On one hand, the smaller community means you miss out on the maturity and battle-testing that adoption in the larger Java ecosystem brings, but on the other hand, you get to write in pure, effectful FP style, if that's your thing.
Yeah, pretty much. Though it falls mostly into two categories:
1) "Haskell on the JVM". Pure functional, algebraic effects, monads, custom operators/DSL's the whole nine yards. This would be the Typelevel ecosystem stuff, and ZIO/Scalaz/FS2/Cats/etc.
(Actually, some of the ZIO stuff is not so wild. I think it's fairly digestible/easy compared to some of the more "hardcore" scala FP libraries)
I can imagine this being an issue if you were working with it in a professional context, or on a team that had differing ideas about what Scala ought to look like.
Being a personal project, I've done a bunch of stuff that you probably wouldn't find recommended online. I am using Quarkus/Vertx Java libs, and a lot of Enterprise Java (javax/jakarta) stuff.
(Note: I actually wrote a Quarkus extension to add support for compiling Scala 3 so that it could be used with Quarkus' ecosystem)
https://github.com/quarkusio/quarkus/pull/18431
That being said, the online Scala community is helpful, even if FP-oriented. On the Discord you'll find deep expertise and answers to most anything you ask.
And believe it or not they won't burn you alive if you say "Hey I'm not really interested in hardcore FP".
I owe a lot of what (little) I know to a handful of members on there (tpolecat, Balmung, Aly, Ethan) who always seem to have time to answer my dumb questions.
>> The way I see it, the TypeLevel compiler was very useful for trying out and refining features that have found their way into the mainline compiler afterwards. (by Martin Odersky
As a Scala user (with not much awareness of the big players in the community), I think the fork worked out nicely. I enjoy the features in Scala 2.13 that were stimulated by the fork. With the impending release of Scala 3 it probably made even more sense to discontinue the fork rather than use it to seed more new features.
For Pure FP there's scala3.com