For Julia there are PyCall and RCall, so the ecosystem is less of an issue than with other languages. Also, its ecosystem has been growing quickly over the last 2 years or so.
Re:From First Principles: Why Scala?
by occupy_paul_st on Thursday February 11, 2021 @10:13AM
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I actually haven't seen a language that can do everything that Scala can do, so in a lot of senses I agree with you!
The alternative is to use multiple different languages to fill different niches. In theory this sounds suboptimal but I think it might actually be easier to learn multiple simpler languages than it is to learn Scala.
BTW according to PYPL: Swift, Kotlin, TypeScript, and Rust are now more popular than Scala.
I've switched to Clojure, it covers all those basis.
F#
I actually came to Scala via F#. You can even find exact dates of those transitions in my stackoverflow history.
Scala and F# are sinilar enough to basically be the same language, though I found F# had a number of warts and idiosyncracies that made me move on to Scala. Scala didn't have all of these (though of course it had warts of its own!) and is what stuck with me for the long term
F# has a much more primitive type system than Scala and isn't particularly impressive imo. And it doesn't have functors ala OCaml.
What I like about F# vs Scala is the ML-style syntax and the relative simplicity. I have found Scala staggeringly complex every time I have tried to learn it, it seems like the C++ of functional programming languages. This impression may be misguided.
Julia, Rust, and Elixir are all great, but popularity, ecosystem are not there yet.