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Scala 2.12.0 is now available

• timothyklim 10y ago
  More details http://get-scala.org/2.12 http://get-scala.org/2.12
  • jinst8gmi 10y ago
    Where can I find more info on the performance work done on collections?
• noelwelsh 10y ago
  The right-biased Either, and the partial unification support that it builds on, are a much needed and much appreciated improvement. Really looking forward to trying out this release.
  • tel 10y ago
    I just learned these were on the table last night. It's like Christmas!
    • deleted 10y ago
      [deleted]
  • eranation 10y ago
    Is there a good source to read about what is partial unification for the uninitiated? Googling it lead me to this: https://issues.scala-lang.org/plugins/servlet/mobile#issue/SI-2712 https://issues.scala-lang.org/plugins/servlet/mobile#issue/S... which points to a formal proof of my functional programming concepts illiteracy (http://www.cs.cmu.edu/~fp/papers/lfp88.pdf http://www.cs.cmu.edu/~fp/papers/lfp88.pdf). Couldn't understand a word and I use scala for work... Any chance there is an easy explanation? Edit: found something: https://gist.github.com/djspiewak/7a81a395c461fd3a09a6941d4cd040f2 https://gist.github.com/djspiewak/7a81a395c461fd3a09a6941d4c...
    • denis1 10y ago
      This is a good explanation about what partial unification means in terms of Scala. And also a pretty good explanation of what the supposed fix actually does. https://gist.github.com/djspiewak/7a81a395c461fd3a09a6941d4cd040f2 https://gist.github.com/djspiewak/7a81a395c461fd3a09a6941d4c...
    • noelwelsh 10y ago
      Was about to post that link when I saw your edit.
    • nicktelford 10y ago
      There's a pretty decent explanation in the release-notes: http://get-scala.org/2.12#partial-unification-of-type-constructors http://get-scala.org/2.12#partial-unification-of-type-constr...
• brianwawok 10y ago
  Does anyone have sample sizes on Jar file size reduction, or clean compile time from the new backend? I haven't been deep in Scala for a few months, and it sounds interesting that Java8 allowed some improvements on the back end...
  • redtuesday 10y ago
    regarding jar size, from http://get-scala.org/2.12 http://get-scala.org/2.12 (mentioned in this thread already): 2.9 2.10 2.11 2.12 Scala library 9.0 7.1 5.7 5.5 Scala compiler 11.5 14.5 15.5 10.1 ScalaTest (3.0.0) 10.5 10.4 7.0 data is in Megabyte. Compilation would be interesting, since I have read multiple times that it is slower due to a jvm bug. Only a few days ago for example: https://www.reddit.com/r/programming/comments/5ab948/scala_212_release_notes/d9f5vsu/ https://www.reddit.com/r/programming/comments/5ab948/scala_2...
    • merb 10y ago
      > since I have read multiple times that it is slower due to a jvm bug extremly depending on your use case (p.s. it's not only compile time slower, but -Xminin-forwarders made it way better, but of course bigger jar files), the jar size, too.
• bad_user 10y ago
  This is the version of Scala that breaks compatibility with Java 6 in the generated bytecode, by making use of Java 8's features, like invokedynamic, default interface methods and integration with SAM types. This is great because the generated bytecode is smaller and more resistant to binary compatibility issues. Scala has had problems with binary compatibility because its features don't map that well on top of the JVM and traits have been very problematic, so thankfully now we have a more efficient encoding. Having SAM support is also good for both Java devs wanting to use Scala libraries and for Scala devs wanting to use Java libraries. But this also means that Scala 2.11 should be a long-term support version, because even though Java 6 and 7 have reached end of life, the world is not ready to fully commit to Java 8, as sadly there are projects like Android that are holding us back. Scala 2.12 is a big achievement, with many changes under the hood. I'm happy to finally see it released. Kudos to those involved.
  • nothrabannosir 10y ago
    ..., the world is not ready to fully commit to Java 8, as sadly there are projects like Android that are holding us back. And GAE standard environment. :(
  • pjmlp 10y ago
    > the world is not ready to fully commit to Java 8, as sadly there are projects like Android that are holding us back. This is only going to get worse after Java 9 and 10 get released. I imagine by the time we get Java 10, Google might be considering to eventually cherry pick Java 9 features. They just forked the whole eco-system, and lots of people blindly post links to their Java 8 references, without looking into Android source code, where they are just cherry picking Java 8 features, JVM bytecodes and libraries.
    • bad_user 10y ago
      Well I was against Oracle suing them with their copyright and patents and I still am, but Google did fragment the Java ecosystem and should be blamed for it. They just pulled an embrace, extend, then fuck it up. I can understand why they wanted to bootstrap their stuff on top of Java, but now they are clearly not committed to keeping up. And with all of their resources, I just won't believe they can't do it.
• mirekrusin 10y ago
  Great stuff but can you please scale up font contrast a bit? Just removing this `body { color: #586E75 }` altogether makes your page readable.
  • foepys 10y ago
    Yes, please. The font color is way too light.
  • gmartres 10y ago
    The maintainers might not see your comment, I encourage you to make a PR: https://github.com/scala/scala-lang https://github.com/scala/scala-lang
• Philipp__ 10y ago
  What grabbed my attention the most in terms of Scala is Dotty. New compiler for Scala, who's main goal is simplification and reorganization of language. You know it will be for real when even Martin is working on it! This language has bright future. Edit: grammar, sry.
  • denis1 10y ago
    Well Martin also worked on scalac, with all its warts & problems, so you can't say that it will be better just because he's also working on it. :) IMO much more important is the fact that Dotty is being developed after several years and iterations of scalac. Ideally this would mean that the problems to be solved, and the different ways to solve them are known. Dotty can do this without having a large legacy inherited code base. To me this is more important.
    • doikor 10y ago
      I think one of the best things about Dotty is that they now have a proven theory that the language works on top of (DOT calculus http://scala-lang.org/blog/2016/02/03/essence-of-scala.html http://scala-lang.org/blog/2016/02/03/essence-of-scala.html). This has allowed them to remove some unsound things (and work around others in a sound way)
    • joostdevries 10y ago
      Have you heard any of his presentations on the new compiler architecture? I'm incredibly impressed with the stewardship of Scala: they did a thorough assessment of the strengths and weaknesses of language and compiler and are working on a complete refoundation of the language semantics and a rewrite of the compiler while also steadily progressing along a multi year roadmap for the current compiler.
      • deleted 10y ago
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  • redtuesday 10y ago
    > This language has bright future. Yeah, it definitely looks good (to me). Dotty looks really promising to a layman like me especially since it's based on the machine-checked DOT calculus, so should have a better foundation than scalac. Then there are big projects like Spark, Akka, Play etc. But what I like the most about Scala at the moment is the continued effort regarding Scala.js, which seems to be one of the best compile-2-javascript projects. I like ur/web, and what comes the closest to it seems to be scala/scala.js. I wonder if the collection redesign which is planned for scala 2.13 helps reduce the file size when compiling to js. Hello world is around ~40 kb (minified and gzipped) but goes to 100-150 kb for more involved things.
• ThePawnBreak 10y ago
  Does anyone have any tips for learning Scala? I want to learn the language, it looks very interesting, and I have some familiarity with Scheme, Haskell and Ocaml, but I just don't know how to start. What should I read? What should I build?
  • mafribe 10y ago
    I have suggested Odersky's introductory MOOC [1] to many of my students and they all thought it was great. It's heavily inspired by SICP, so it should be easy, given your background. [1] https://www.coursera.org/learn/progfun1 https://www.coursera.org/learn/progfun1
    • wpietri 10y ago
      Yes, I second the recommendation for the course. And I can happily recommend it for people who don't even plan to use Scala, but who just want to get a feel for functional vs OO approaches. Odersky sees them as complimentary, and in some sense Scala is his way of proving the point.
  • kod 10y ago
    If you just want to learn the language, read scala for the impatient, first half is free on Lightbend's website. If you want to learn fp, read functional programming in scala (Manning).
  • 0xmohit 10y ago
    I'm reminded of "The State of Scala website and documentation" [0]. [0] https://groups.google.com/forum/#!topic/scala-internals/r2GnzCFc3TY https://groups.google.com/forum/#!topic/scala-internals/r2Gn...
  • paul_blei 10y ago
    take a look at: http://blog.codacy.com/2015/07/03/how-to-learn-scala/ http://blog.codacy.com/2015/07/03/how-to-learn-scala/
  • doikor 10y ago
    The https://www.scala-exercises.org/ https://www.scala-exercises.org/ is a good source (though it is just exercises so might not be the best first material) Great thing about it is that you can do it in a browser without setting up anything (requires a github account)
• amelius 10y ago
  Offtopic. Does anybody know of a practical imperative language in which promises are implicit? Often, when writing software, it happens that deeply nested functions suddenly have to return a promise instead of a direct value, and this forces the programmer to rewrite all the callers of that function into dealing with promises, which of course sucks. So it would be better if the programming language would do that rewriting instead (under the hood), so to speak.
  • dragandj 10y ago
    You are literally describing monads.
  • dewiz 10y ago
    looks like async/await (C#) is close to what you're looking for.
  • joostdevries 10y ago
    There's Async Await. Which makes asynchronous code look like regular blocking code. But the calling code needs to know about it. I recognise your concern: asynchronicity is infectious if it's manifested as monads. Which sucks. Client code needs to know whether the code it is calling is blocking or asynchronous. Maybe effect systems can trace through code whether it is 'infected' with blockingness. Without any change showing in the intermediary source code. The blockingness/non-blockingness only manifesting itself at the top of the call graph.
  • runT1ME 10y ago
    This is what monadic syntax is for. You can do the following for any Future in scala: for { resa <- asyncCall(1) resb <- asyncCall(2) resc <- asyncCall(3) } yield new Obj(resa, resb, resc) which just gets rewritten to asyncCall(1).flatMap(resa => asyncCall(2).flaMap(resb => asyncCall(3).map(resc => new Obj(resa, resb, resc)))) This doesn't just work for futures, it works for any monad. This is super amazingly useful. Also, query syntax for LINQ in C#/F# can support this too.
    • 10y ago
• lacampbell 10y ago
  I desperately want to like Scala. An expressive, concise pure OO Lang with static typing designed for a REPL is something I often wish existed. But every time I've used it I've come away disappointed with the execution. A bewildering standard library, a type system that crashes, glacial compilation, and the sbt repl leaks memory every time you type a command. I'll try it again, as I believe it's an excellent idea. Having objects so fine grained allows it to emulate functional programming really well. But I suspect I'll be disappointed again.
  • whateveracct 10y ago
    When was the last time you tried Scala? I just left a Scala/scalaz job after around 2 years and everyone I worked with was extremely happy with the language. We gradually moved to a more Haskell-like approach to programming, which I feel Scala is more capable of than any other mature general-purpose language (except Haskell ofc) I'll address your issues one-by-one. > A bewildering standard library What about it troubled you? The main things I use in the stdlib are collections (CanBuildFrom aside, they're pretty solid), Future (although I prefer scalaz.concurrent.Task), and Option. In 2.12, Either is finally usable too! > a type system that crashes I've only run into a single type checker crash (NPE) in my 2 years. Aside from that, the type system has become my best friend. I write implicit-heavy code that leans on scalaz and shapeless too. > glacial compilation A full compile of our ~250 file (idr loc) service took like 2 minutes. But I pretty much never did full compiles. Sbt incremental compilation of a handful of files would take a coupe seconds. This makes the feedback loop of running tests/the repl pretty quick, and unlike with other fast-feedback-loop languages (like Ruby), I get really strong checks from the compiler in each loop. > the sbt repl leaks memory every time you type a command. Are you referring to the Scala repl (sbt console) or the sbt build tool prompt? It's true that the repl leaks memory but that's by design: every repl evaluation is stored in a variable (res0, res1, etc). I've run into memory trouble once or twice when loading large production data into the repl, which would store it in one of these variables. I worked around it by loading it but then in a block extracting what I needed. This smaller data would in turn be stored in resX.
    • lacampbell 10y ago