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Blog Post: Announcing Dotty 0.6.0 and 0.7.0-RC1 #4053

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157 changes: 157 additions & 0 deletions docs/blog/_posts/2018-03-05-seventh-dotty-milestone-release.md
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---
layout: blog-page
title: Announcing Dotty 0.6.0 and 0.7.0-RC1
author: Allan Renucci
authorImg: /images/allan.jpg
date: 2018-03-05
---

Today, we are excited to release Dotty versions 0.6.0 and 0.7.0-RC1. These releases
serve as a technology preview that demonstrates new language features and the compiler supporting them.

If you’re not familiar with Dotty, it's a platform to try out new language concepts and compiler
technologies for Scala. The focus is mainly on simplification. We remove extraneous syntax
(e.g. no XML literals), and try to boil down Scala’s types into a smaller set of more fundamental
constructs. The theory behind these constructs is researched in
[DOT](https://infoscience.epfl.ch/record/215280), a calculus for dependent object types.
You can learn more about Dotty on our [website](http://dotty.epfl.ch).

<!--more-->

This is our seventh scheduled release according to our [6-week release schedule](/docs/usage/version-numbers.html).
The [previous technology preview](https://github.com/lampepfl/dotty/releases/tag/0.6.0-RC1) focussed
on bug fixes and stability work.

## What’s new in the 0.7.0-RC1 technology preview?

### Enums Simplicification [#4003](https://github.com/lampepfl/dotty/pull/4003)
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Typo: Simplification

The previously introduced syntax and rules for enum were arguably too complex. We can considerably
simplify them by taking away one capability: that cases can have bodies which can define members.
Arguably, if we choose an ADT decomposition of a problem, it's good style to write all methods using
pattern matching instead of overriding individual cases. So this removes an unnecessary choice.
We now treat enums unequivocally as classes. They can have methods and other statements just like
other classes can. Cases in enums are seen as a form of constructors. We do not need a
distinction between enum class and enum object anymore. Enums can have companion objects just like
normal classes can, of course.

Let's consider how `Option` can be represented as an enum. Previously using an enum class:
```scala
enum class Option[+T] {
def isDefined: Boolean
}
object Option {
case Some[+T](x: T) {
def isDefined = true
}
case None {
def isDefined = false
}

def apply[T(x: T): Option[T] = if (x == null) None else Some(x)
}
```

And now:
```scala
enum Option[+T] {
case Some(x: T)
case None

def isDefined: Boolean = this match {
case None => false
case some => true
}
}

object Option {
def apply[T](x: T): Option[T] = if (x == null) None else Some(x)
}
```

You can visit our website for more information about [enumerations](/docs/reference/enums/enums.html)
and how we can use them to model [Algebraic Data Types](/docs/reference/enums/adts.html).
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Are these links up-date?

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These links will become valid once the page is generated. An alternative would be to write absolute links (e.g. http://dotty.epfl.ch/docs/reference/enums/enums.html) so that they are also valid links in GitHub

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Sorry: I was asking if the docs in the target pages have been updated (and I thought not).


### Unused Parameters [#3342](https://github.com/lampepfl/dotty/pull/3342)
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@nicolasstucki Do you want to do this?

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@nicolasstucki Probably we should say a couple words about going from phantom types to unused parameters (#2040 (comment)), probably in the release notes rather than in the docs for the latest release (to avoid confusing new users). Starting point:

TL;DR: With unused parameters you can mark values of arbitrary types to be erased at runtime, instead of having to implement separate phantom types.

TODO

## Trying out Dotty
### Scastie
[Scastie], the online Scala playground, supports Dotty.
This is an easy way to try Dotty without installing anything.

### sbt
Using sbt 0.13.13 or newer, do:

```shell
sbt new lampepfl/dotty.g8
```

This will setup a new sbt project with Dotty as compiler. For more details on
using Dotty with sbt, see the
[example project](https://github.com/lampepfl/dotty-example-project).

### IDE support
It is very easy to start using the Dotty IDE in any Dotty project by following
the [IDE guide](http://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)

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 0.6.0-RC1..0.7.0-RC1` these are:

```
TODO
```

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](http://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
[@Blaisorblade]: https://github.com/Blaisorblade
[@Duhemm]: https://github.com/duhemm