Merge pull request #5517 from dotty-staging/0.11-blogpost

[WIP] Dotty 0.11.0-RC1 blog post

Author: allanrenucci

docs/blog/_posts/2018-11-30-11th-dotty-milestone-release.md

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+---
+layout: blog-page
+title: Announcing Dotty 0.11.0-RC1
+author: Allan Renucci
+authorImg: /images/allan.jpg
+date: 2018-11-30
+---
+
+Today we are excited to release Dotty version 0.11.0-RC1.
+This release serves as a technology preview that demonstrates new language features and the
+compiler supporting them.
+
+Dotty is the project name for technologies that are considered for inclusion in Scala 3. Scala has
+pioneered the fusion of object-oriented and functional programming in a typed setting. Scala 3 will
+be a big step towards realising the full potential of these ideas. Its main objectives are to
+
+- become more opinionated by promoting programming idioms we found to work well,
+- simplify where possible,
+- eliminate inconsistencies and surprising behaviours,
+- build on strong foundations to ensure the design hangs well together,
+- consolidate language constructs to improve the language’s consistency, safety, ergonomics, and
+  performance.
+
+You can learn more about Dotty on our [website](https://dotty.epfl.ch).
+
+<!--more-->
+
+This is our 11th scheduled release according to our
+[6-week release schedule](https://dotty.epfl.ch/docs/usage/version-numbers.html).
+
+## What’s new in the 0.11.0-RC1 technology preview?
+
+### Opaque Type Aliases
+
+Opaque types aliases provide type abstraction without any overhead. Example:
+
+```scala
+opaque type Duration = Long
+```
+
+This introduces `Duration` as a new type, which is implemented as a `Long` but is different from
+it. The fact that `Duration` is the same as `Long` is only known in the companion object of
+`Duration`. Here is a possible companion object:
+
+```scala
+object Duration {
+
+  // These are the ways to lift to the Duration type
+  def fromNanos(duration: Long): Duration = duration
+  def fromSeconds(duration: Long): Duration = duration * 1000000000
+
+  // This is the first way to unlift the Duration type
+  def toNanos(l: Duration): Long = l
+
+  // Extension methods define opaque types' public APIs
+  implicit class DurationOps(self: Duration) extends AnyVal {
+    // This is the second way to unlift the Duration type
+    def toSeconds: Long = self / 1000000000
+    def + (that: Duration): Duration = self + that
+  }
+}
+```
+
+The companion object contains the `fromNanos` and `fromSeconds` methods that convert from longs to
+`Duration` values. It also adds a `toNanos` function and a decorator that implements `+` on
+duration values, as well as a conversion `toSeconds`. All of this is possible because within object
+`Duration`, the type `Duration` is just an alias of `Long`.
+
+Outside the companion object, `Duration` is treated as a new abstract type. So the following
+operations would be valid because they use functionality implemented in the `Duration`
+object.
+
+```scala
+val d1 = Duration.fromNanos(1000L)
+val d2 = Duration.fromSeconds(2L)
+val d3 = d1 + d2
+```
+
+But the following operations would lead to type errors:
+
+```scala
+val l: Long = d1      // error: found: Duration, required: Long
+val d: Duration = 3L  // error: found: Long(3L), required: Duration
+d1 + 2L               // error: found: Long(2L), required: Duration
+d1 - d2               // error: `-` is not a member of Duration
+```
+
+### Worksheet Mode Support in Visual Studio Code
+
+Dotty IDE can now be used in Worksheet mode. A worksheet is a Scala file that is evaluated on save,
+and the result of each expression is displayed in a column on the right of your program. Worksheets
+are like a REPL session on steroids, and enjoy 1st class editor support: completions, hyperlinking,
+interactive errors-as-you-type, etc.
+
+![]({{ site.baseurl }}/images/worksheets/worksheet-demo.gif "Run worksheet")
+
+For more information about the worksheets, see [Worksheet mode with Dotty
+IDE](http://dotty.epfl.ch/docs/usage/worksheet-mode.html)
+
+### Various IDE improvements
+
+#### Help with method signatures
+
+When writing a method call, Dotty IDE will now show contextual information that helps filling in the
+arguments of the method.
+
+![]({{ site.baseurl }}/images/dotty-ide/signature-help.png "Signature help")
+
+#### Improved display of documentation in Dotty IDE
+
+In this release, we reworked how we show documentation inside the IDE. We now extract usefull
+information from the Scaladoc comment, then format it before we display it in the IDE.
+
+![]({{ site.baseurl }}/images/dotty-ide/documentation-hover.png "Documentation hover")
+
+### And much more!
+
+Please read our [release notes](https://github.com/lampepfl/dotty/releases/tag/0.11.0-RC1)
+for more details!
+
+## Trying out Dotty
+
+### sbt
+
+You can setup a new sbt project with Dotty as the compiler by running:
+
+```shell
+sbt new lampepfl/dotty.g8
+```
+
+For more details on using Dotty with sbt, see the
+[example project](https://github.com/lampepfl/dotty-example-project).
+
+### [Mill](http://www.lihaoyi.com/mill/)
+
+The Mill build tool version 0.2.6 introduced experimental support for Dotty. For more details on
+using Dotty with Mill, see the
+[example project](https://github.com/lampepfl/dotty-example-project/tree/mill).
+
+### IDE support
+
+Start using the Dotty IDE in any Dotty project by following
+the [IDE guide](https://dotty.epfl.ch/docs/usage/ide-support.html).
+
+### Standalone installation
+
+Releases are available for download on the _Releases_
+section of the Dotty repository:
+[https://github.com/lampepfl/dotty/releases](https://github.com/lampepfl/dotty/releases)
+
+For MacOs users, we also provide a [homebrew](https://brew.sh/) package that can be installed by
+running:
+
+```shell
+brew install lampepfl/brew/dotty
+```
+
+In case you have already installed Dotty via `brew`, you should instead update it:
+
+```shell
+brew upgrade dotty
+```
+
+## Let us know what you think!
+
+If you have questions or any sort of feedback, feel free to send us a message on our
+[Gitter channel](https://gitter.im/lampepfl/dotty). If you encounter a bug, please
+[open an issue on GitHub](https://github.com/lampepfl/dotty/issues/new).
+
+## Contributing
+
+Thank you to all the contributors who made this release possible!
+
+According to `git shortlog -sn --no-merges 0.10.0..0.11.0-RC1` these are:
+
+```
+   143  Martin Duhem
+   104  Nicolas Stucki
+    82  Martin Odersky
+    60  Guillaume Martres
+    35  Allan Renucci
+    21  poechsel
+    12  Olivier Blanvillain
+    10  Liu Fengyun
+     8  Aleksander Boruch-Gruszecki
+     6  Tobias Bordenca
+     5  Sébastien Doeraene
+     4  Stéphane Micheloud
+     3  João Pedro Evangelista
+     3  Miles Sabin
+     3  Neeraj Jaiswal
+     3  Abel Nieto
+     2  Ólafur Páll Geirsson
+     2  Fengyun Liu
+     2  veera venky
+     1  mikhail
+     1  Glavo
+     1  0xflotus
+     1  Paolo G. Giarrusso
+```
+
+If you want to get your hands dirty and contribute to Dotty, now is a good time to get involved!
+Head to our [Getting Started page for new contributors](https://dotty.epfl.ch/docs/contributing/getting-started.html),
+and have a look at some of the [good first issues](https://github.com/lampepfl/dotty/issues?q=is%3Aissue+is%3Aopen+label%3Aexp%3Anovice).
+They make perfect entry points into hacking on the compiler.
+
+We are looking forward to having you join the team of contributors.
+
+## Library authors: Join our community build
+
+Dotty now has a set of widely-used community libraries that are built against every nightly Dotty
+snapshot. Currently this includes ScalaPB, algebra, scalatest, scopt and squants.
+Join our [community build](https://github.com/lampepfl/dotty-community-build)
+to make sure that our regression suite includes your library.
+
+[Scastie]: https://scastie.scala-lang.org/?target=dotty
+
+[@odersky]: https://github.com/odersky
+[@DarkDimius]: https://github.com/DarkDimius
+[@smarter]: https://github.com/smarter
+[@felixmulder]: https://github.com/felixmulder
+[@nicolasstucki]: https://github.com/nicolasstucki
+[@liufengyun]: https://github.com/liufengyun
+[@OlivierBlanvillain]: https://github.com/OlivierBlanvillain
+[@biboudis]: https://github.com/biboudis
+[@allanrenucci]: https://github.com/allanrenucci
+[@Blaisorblade]: https://github.com/Blaisorblade
+[@Duhemm]: https://github.com/Duhemm