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From First Principles: Why Scala?

lihaoyi.com

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Re: From First Principles: Why Scala?

#41

Post by MrPowers »

adenozine wrote: post #3

If I've said it once I've said it a thousand times: the day Scala kills sbt officially will be the day thousands of devs consider a return to it. Until then, I couldn't dare.

Perhaps the better way to phrase this is "the day Lightbend deprecates SBT and tells the community to use Mill", but I agree with the sentiment.

Scala needs a new "official stack", hopefully Mill + utest/Munit + scalafmt (with opinionated settings).

Scala 3 + SBT + Scalatest + whatever formatting isn't going to grab folk's attention.

Re: From First Principles: Why Scala?

#42

Post by _a1_ »

bjarneh wrote: post #17

Scala is one of those great languages with that one Achilles heel. The speed of that compiler: $ time scalac Hello.scala real 0m2,907s user 0m7,901s sys 0m0,308s $ cat Hello.scala object Hello{ def main(args: Array[String]){ println("hello world") } } Implicit type conversion can be debated I guess, but otherwise a very beautiful language.

Using scalac is not a standard use case.

Standard use case is to use sbt (well, or mill, since we're in lihaoyi's thread :D). Sbt starts up slow, but with bloop, or sbtn (native client of sbt), the compilation is really fast (much faster than C++ for example):

    $ time sbtc compile                                                                          
    [info] entering *experimental* thin client - BEEP WHIRR
    [info] terminate the server with `shutdown`
    > compile
    [info] compiling 1 Scala source to /home/.../target/scala-2.13/classes ...
    [info] compile completed
    [success] Total time: 0 s, completed Feb 11, 2021 4:21:51 PM
    sbtc compile  0,08s user 0,02s system 21% cpu 0,492 total

Re: From First Principles: Why Scala?

#43

Post by Cthulhu_ »

dominotw wrote: post #40
MrPowers wrote: post #36

I am a Scala programmer & think it's a great language. Here are some arguments for why not Scala: * Li's libs (os-lib, upickle, utest) have clean public interfaces, but most Scala ecosystem libs are hard to use, see the JSON alternatives for examples: https://www.lihaoyi.com/post/uJsonfastflexibleandintuitiveJS... * The Mill build tool looks a lot better than SBT, but seems like everyone is still using SBT * Scala mi…

> Hard to win technical arguments with Scala geniuses that like using complicated language features. I was on a team building good old crud apps using monads, monoids, categories, combinators, effects cats, seamless and bunch of other nonsense that i've now purged from my brain. You could've easily mistaken our team for a programming language research group at a university. This is literally the number one reason i w…

This is my biggest gripe with Scala as well. I'm sure it's a great language, but I've often seen it used to add complexity where none is necessary. It's abused to give developers a sense of accomplishment and intellectual superiority.

In fact, in one project my former employer was involved in, one main reason they picked Scala was to, on the one hand, weed out the chaff from their existing team of .net developers (in a "shape up or ship out" kind of fashion), and on the other to weed out the 95% of mediocre Java developers.

Re: From First Principles: Why Scala?

#44

Post by atbpaca »

I think that the Scala experience will get even better with Scala 3, tons of well thought refactorings for metaprogramming and typeclasses, among others. Also, looking forward to (optional) indentation based syntax.

Re: From First Principles: Why Scala?

#45

Post by UglyGenius »

aynyc wrote: post #15

Is Scala used outside of Spark and Akka? Spark is my company chosen analytic engine, Scala was/is the main language for majority of the production workload. In the last two years or so, more devs are writing PySpark and SparkSQL jobs than Scala.

There's a blooming ecosystem of pure functional programming libraries. Or even two ecosystems: Typelevel and ZIO.

My company uses Scala a lot with with these ecosystems (my team is on Typelevel, another one is on ZIO) and in fact Spark and Akka is what we're trying to avoid as much as possible. Once I got used to the composable nature of FP and static types - both Spark and Akka just feel clumsy and unintuitive, like maintainers of Spark chose Scala because it was a "Java with fancy syntax" back then, ignored most of benefits of static types, HKT, immutability, type classes etc. If there's future behind Scala - it definitely doesn't lie in Apache land. Akka is slightly different and probably has higher potential, but just an overkill for most of use cases it's advertised for.

Re: From First Principles: Why Scala?

#46

Post by Cthulhu_ »

occupy_paul_st wrote: post #11

I definitely agree that many newer languages are strongly inspired by Scala, but I don't see a strong argument for why to choose Scala over one of a newer hybrid language. My own intuition is that these newer languages have had the benefit of being able to learn from Scala's mistakes. A lot of them have intentionally sacrificed some of the Scala's flexibility to be easier to learn and use. I found Scala to be an extr…

I feel like Scala started a trend in language design, where every language adds features from other languages. Not because there's a need, but because some people are used to language X.

Example: adding OOP in PHP and Javascript. In both examples, especially the first attempts, were half-baked. Why bolt on half a language feature? Both languages would be much better served with dependency management and / or modules, which for both languages came out of the community at first.

Counter-example would be Go, that resists change - especially if it's requested with a "this feature is in language X! I NEED it!". From the FAQ: https://golang.org/doc/faq#Why_doesnt_Go_have_feature_X (followed by some features other languages have. Generics / type arguments is one that will probably be added in an upcoming version of Go, but they only considered it once they fully understood the problem and need)

Re: From First Principles: Why Scala?

#48

Post by ibains »

Prophecy.io - low code product for data engineering on Spark - is Scala based - we love it! We do compiler work - and packrat parser combinators are great.

Basic things are supported well. We use Play. We have GraphQL in web services - use Sangria. Slick FRM for database access is very clean. We use Akka for live web socket connections to Spark for interactive execution.

We extend Spark code from outside when needed - adding functions to classes in imported libraries.

It’s a learning curve for new engineers, but we hire the best and they like Scala after using it for a bit. SBT is confusing as hell, build times were painful but getting better. Debugging is sometimes hard (implicits)

One thing I’ve learnt us that if you’re handed a gun, you don’t have to start shooting at your feet just because you can. We used C++ at NVIDIA sensibly a decade back - using OOP but still avoiding horrible parts of C++. We use Scala sensibly now.

Can’t imagine another language that would work for us. I’ve used C, C++, F# before (building compilers and databases)- don’t know Kotlin. Only other language we use is Golang for our kubernetes operator (excluding UI)

Re: From First Principles: Why Scala?

#49

Post by zepto »

agbell wrote: post #16
mark_l_watson wrote: post #7

Earlier quoted context omitted.

I am working on an AI book using Swift. Yesterday in a meeting, my manager was asking why Swift. I compared it to Scala, but built on LLVM, and a rich CoreML and other library infrastructure. REPL + closures, very fast build times. I haven’t had much opportunity to use Scala, but I did take Martin’s Functional Programming with Scala course years ago, and that was great.

Scala is a great language. I haven't done that coursera course, but many people swear by it. To me, Swift and Kotlin look like they have taken inspiration from Scala. I think Kotlin explicitly did. That idea transfer from one area to another is how we get better langauges.

Having programmed professionally in both Scala, and Swift, and enjoyed both, I can see basically nothing that Swift takes from Scala.

The common ancestor is OCaml, and the ML languages in general.

To be fair, that may change as Swift adopts Actor based concurrency.

Re: From First Principles: Why Scala?

#50

Post by MrPowers »

dominotw wrote: post #40
MrPowers wrote: post #36

I am a Scala programmer & think it's a great language. Here are some arguments for why not Scala: * Li's libs (os-lib, upickle, utest) have clean public interfaces, but most Scala ecosystem libs are hard to use, see the JSON alternatives for examples: https://www.lihaoyi.com/post/uJsonfastflexibleandintuitiveJS... * The Mill build tool looks a lot better than SBT, but seems like everyone is still using SBT * Scala mi…

> Hard to win technical arguments with Scala geniuses that like using complicated language features. I was on a team building good old crud apps using monads, monoids, categories, combinators, effects cats, seamless and bunch of other nonsense that i've now purged from my brain. You could've easily mistaken our team for a programming language research group at a university. This is literally the number one reason i w…

In the Spark world, you can use a tiny subset of the Scala features and enjoy huge productivity gains over the other language APIs (Java & Python). Those productivity gains are wiped out as more crazy language features get used.

I don't think the super complex language features should be removed. Li's libs do some crazy stuff under the hood, but provide a clean, Python-like public interface. Most devs aren't that good and complex underlying implementations leak and yield complex public interfaces.

Lots of folks would love Scala codebases that only use 10% of the available language features and none of the complex frameworks. But, like you mentioned, it's a hard language to use responsibly.

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