SCALA 2.11.0 IS NOW AVAILABLE!

• Get started with the Hello Scala 2.11 template in Typesafe Activator
• Download a distribution from scala-lang.org
• Obtain it via Maven Central

New features in the 2.11 series

• Collections
  • Immutable HashMaps and HashSets perform faster filters, unions, and the like, with improved structural sharing (lower memory usage or churn).
  • Mutable LongMap and AnyRefMap have been added to provide improved performance when keys are Long or AnyRef (performance enhancement of up to 4x or 2x respectively).
  • BigDecimal is more explicit about rounding and numeric representations, and better handles very large values without exhausting memory (by avoiding unnecessary conversions to BigInt).
  • List has improved performance on map, flatMap, and collect.
  • See also Deprecation above: we have slated many classes and methods to become final, to clarify which classes are not meant to be subclassed and to facilitate future maintenance and performance improvements.
• Modularization
  • The core Scala standard library jar has shed 20% of its bytecode. The modules for xml, parsing, swing as well as the (unsupported) continuations plugin and library are available individually or via scala-library-all. Note that this artifact has weaker binary compatibility guarantees than scala-library – as explained above.
  • The compiler has been modularized internally, to separate the presentation compiler, scaladoc and the REPL. We hope this will make it easier to contribute. In this release, all of these modules are still packaged in scala-compiler.jar. We plan to ship them in separate JARs in 2.12.x.
• Reflection, macros and quasiquotes
  • Please see this detailed changelog that lists all significant changes and provides advice on forward and backward compatibility.
  • See also this summary of the experimental side of the 2.11 development cycle.
  • #3321 introduced Sprinter, a new AST pretty-printing library! Very useful for tools that deal with source code.
• Back-end
  • The GenBCode back-end (experimental in 2.11). See @magarciaepfl’s extensive documentation.
  • A new experimental way of compiling closures, implemented by @JamesIry. With-Ydelambdafy:method anonymous functions are compiled faster, with a smaller bytecode footprint. This works by keeping the function body as a private (static, if nothis reference is needed) method of the enclosing class, and at the last moment during compilation emitting a small anonymous class that extends FunctionN and delegates to it. This sets the scene for a smooth migration to Java 8-style lambdas (not yet implemented).
  • Branch elimination through constant analysis #2214
  • Scala.js, a separate project, provides an experimental JavaScript back-end for Scala 2.11. Note that it is not part of the standard Scala distribution.
  • Be more Avian– friendly.
• Compiler Performance
  • Incremental compilation has been improved significantly. To try it out, upgrade to sbt 0.13.2 and add incOptions := incOptions.value.withNameHashing(true) to your build! Other build tools are also supported. More info at this sbt issue – that’s where most of the work happened. More features are planned, e.g. class-based tracking.
  • We’ve been optimizing the batch compiler’s performance as well, and will continue to work on this during the 2.11.x cycle.
  • Improve performance of reflection SI-6638
• The IDE received numerous bug fixes and improvements!
• REPL
  • The bytecode decompiler command, :javap, now works with Java 7 SI-4936 and has sprouted new options SI-6894 (Thanks, @som-snytt!)
  • Added command :kind to help to tell ground types from type constructors. #2340(Thanks, George Leontiev and Eugene Yokota!)
  • The interpreter can now be embedded as a JSR-223 Scripting Engine SI-874. (Thanks,Raphael Jolly!)
• Improved -Xlint warnings
  • Warn about unused private / local terms and types, and unused imports.
  • This will even tell you when a local var could be a val.
• Slimming down the compiler
  • The experimental .NET backend has been removed from the compiler.
  • Scala 2.10 shipped with new implementations of the Pattern Matcher and the Bytecode Emitter. We have removed the old implementations.
  • Search and destroy mission for ~5000 chunks of dead code. #1648

Reporting Bugs / Known Issues

Scala IDE for Eclipse

Available projects

"org.scalacheck"                   %% "scalacheck"                % "1.11.3"

"org.scalatest"                    %% "scalatest"                 % "2.1.3"

"org.scalautils"                   %% "scalautils"                % "2.1.3"

"com.typesafe.akka"                %% "akka-actor"                % "2.3.2"

"com.typesafe.scala-logging"       %% "scala-logging-slf4j"       % "2.0.4"

"org.scala-lang.modules"           %% "scala-async"               % "0.9.1"

"org.scalikejdbc"                  %% "scalikejdbc-interpolation" % "2.0.0-beta1"

"com.softwaremill.scalamacrodebug" %% "macros"                    % "0.4"

"com.softwaremill.macwire"         %% "macros"                    % "0.6"

"com.chuusai"                      %% "shapeless"                 % "1.2.4"

"com.chuusai"                      %% "shapeless"                 % "2.0.0"

"org.nalloc"                       %% "optional"                  % "0.1.0"

"org.scalaz"                       %% "scalaz-core"               % "7.0.6"

"com.nocandysw"                    %% "platform-executing"        % "0.5.0"

"com.qifun"                        %% "stateless-future"          % "0.1.1"

"com.github.scopt"                 %% "scopt"                     % "3.2.0"

"com.dongxiguo"                    %% "fastring"                  % "0.2.4"

"com.github.seratch"               %% "ltsv4s"                    % "1.0.0"

"com.googlecode.kiama"             %% "kiama"                     % "1.5.3"

"org.scalamock"                    %% "scalamock-scalatest-support" % "3.0.1"

"org.scalamock"                    %% "scalamock-specs2-support"  % "3.0.1"

"com.github.nscala-time"           %% "nscala-time"               % "1.0.0"

"com.github.xuwei-k"               %% "applybuilder70"            % "0.1.2"

"com.github.xuwei-k"               %% "nobox"                     % "0.1.9"

"org.typelevel"                    %% "scodec-bits"               % "1.0.0"

"org.typelevel"                    %% "scodec-core"               % "1.0.0"

"com.sksamuel.scrimage"            %% "scrimage"                  % "1.3.20"

"net.databinder"                   %% "dispatch-http"             % "0.8.10"

"net.databinder"                   %% "unfiltered"                % "0.7.1"

"io.argonaut"                      %% "argonaut"                  % "6.0.4"

"org.specs2"                       %% "specs2"                    % "2.3.11"

"com.propensive"                   %% "rapture-core"              % "0.9.0"

"com.propensive"                   %% "rapture-json"              % "0.9.1"

"com.propensive"                   %% "rapture-io"                % "0.9.1"

"org.scala-stm"                    %% "scala-stm"                 % "0.7"

"org.scalafx"            %% "scalafx"            % "8.0.0-R4"

"org.scalafx"            %% "scalafx"            % "1.0.0-R8"

"org.scalamacros"        %% "paradise"           % "2.0.0-M7"

"com.clarifi"            %% "f0"                 % "1.1.1"

"org.parboiled"          %% "parboiled-scala"    % "1.1.6"

"org.monifu"             %% "monifu"             % "0.4"

Cross-building with sbt 0.13

scalaVersion        := "2.11.0"



crossScalaVersions  := Seq("2.11.0", "2.10.3")



// add scala-xml dependency when needed (for Scala 2.11 and newer)

// this mechanism supports cross-version publishing

libraryDependencies := {

  CrossVersion.partialVersion(scalaVersion.value) match {

    case Some((2, scalaMajor)) if scalaMajor >= 11 =>

      libraryDependencies.value :+ "org.scala-lang.modules" %% "scala-xml" % "1.0.1"

    case _ =>

      libraryDependencies.value

  }

}

Important changes

• SI-4577 Compile x match { case _ : Foo.type => } to Foo eq x, as specified. It used to be Foo == x (without warning). If that’s what you meant, write case Foo =>.
• SI-7475 Improvements to access checks, aligned with the spec (see also the linked issues). Most importantly, private members are no longer inherited. Thus, this does not type check:class Foo[T] { private val bar: T = ???; new Foo[String] { bar: String } }, as the bar in bar: String refers to the bar with type T. The Foo[String]’s baris not inherited, and thus not in scope, in the refinement. (Example from SI-8371, see alsoSI-8426.)

• SI-6809 Case classes without a parameter list are no longer allowed.
• SI-7618 Octal number literals no longer supported.

• SI-7296 Case classes with > 22 parameters are now allowed.
• SI-3346 Implicit arguments of implicit conversions now guide type inference.
• SI-6240 Thread safety of reflection API.
• #3037 Experimental support for SAM synthesis.
• #2848 Name-based pattern-matching.
• SI-6169 Infer bounds of Java-defined existential types.
• SI-6566 Right-hand sides of type aliases are now considered invariant for variance checking.
• SI-5917 Improve public AST creation facilities.
• SI-8063 Expose much needed methods in public reflection/macro API.
• SI-8126 Add -Xsource option (make 2.11 type checker behave like 2.10 where possible).

Deprecations

• SI-7605 Procedure syntax (only under -Xfuture).
• SI-5479 DelayedInit. We will continue support for the important extends App idiom. We won’t drop DelayedInit until there’s a replacement for important use cases. (More details and a proposed alternative.)
• SI-6455 Rewrite of .withFilter to .filter: you must implement withFilter to be compatible with for-comprehensions.
• SI-8035 Automatic insertion of () on missing argument lists.
• SI-6675 Auto-tupling in patterns.
• SI-7247 NotNull, which was never fully implemented – slated for removal in 2.12.
• SI-1503 Unsound type assumption for stable identifier and literal patterns.
• SI-7629 View bounds (under -Xfuture).

• #3103, #3191, #3582 Collection classes and methods that are (very) difficult to extend safely have been slated for being marked final. Proxies and wrappers that were not adequately implemented or kept up-to-date have been deprecated, along with other minor inconsistencies.
• scala-actors is now deprecated and will be removed in 2.12; please follow the steps in theActors Migration Guide to port to Akka Actors
• SI-7958 Deprecate scala.concurrent.future and scala.concurrent.promise
• SI-3235 Deprecate round on Int and Long (#3581).
• We are looking for maintainers to take over the following modules: scala-swing, scala-continuations. 2.12 will not include them if no new maintainer is found. We will likely keep maintaining the other modules (scala-xml, scala-parser-combinators), but help is still greatly appreciated.

Binary Compatibility

FORWARDS AND BACK

META

CONCRETELY

License clarification