About Scala IDE and Java 7

Mon Feb 20 00:00:00 -0800 2012

One of the comment from the roadmap post was asking “When is Java 7 support planned?”. This is likely to be a recurring question, so let me take some time to describe the current state.

Using Java 7

The question can be understood in two ways. The first one is “When can I start to use Java 7 with Scala IDE?”. And the answer is: right now.

Eclipse 3.6.2 is able to run Java 7, and the full support is part of version 3.7.1. Scala 2.9.1 is compiled for Java 5 and can be run on Java 7. The same is true for Scala IDE. So there is nothing stopping someone to use Java 7 for its whole setup. And from the information provided in tickets, some users do use Java 7.

That said, it might not be without problems. Eclipse 3.6.2 does not provide support for the new language features from Java 7, and some obscure problem are still being reported against Eclipse 3.7.1 (#364735). The changes in the Java Standard Library in version 7 might require changes in the user’s Scala code, which then make it incompatible with Java 6 or earlier (forum post). At least one ticket specific to Java 7 has but opened against Scala IDE (#1000820).

Explicit Java 7 support

The second way the question can be understood is “When will Java 7 be on the recommended list of VMs?”. Short answer: not planned right now.

The documentation will continue for the time being to discourage users to run Scala IDE on Java 7, at least until the problems occurring when running Eclipse on Java 7 have been clearly identified.

Eclipse support aside, there is no effort planned to solve potential problems specific to Scala IDE when running it on Java 7. It is a simple problem of resources and priorities. A big part of the contributors are using Mac OS X, for which there is currently no release version of Java 7. Of the other contributors, none has expressed an interest in taking on this task.

But Scala IDE is an open source project, and contribution are always welcome.

If you are using Java 7 and find Java 7 specific problems in Scala IDE, do create tickets.

Happy coding.

Eclipse command line installation

Fri Feb 10 00:00:00 -0800 2012

When working on the Scala IDE I often need to install and uninstall the Scala plugin. Sometimes I need to use the Scala trunk version, other times I need to reproduce a bug in an older version, or simply I need to change to the next nightly. Although I have several Eclipse installations, I still need to tinker with them.

Doing it using the UI is tedious, and requires two restarts: one when you uninstall the feature, and another one when you (re-)install the new one. On top of it, it requires clicking around – how many times did I click Cancel instead of Continue, when faced with the unsigned warning? – and in the end it can take several minutes.

The Eclipse director application

Few people know that Eclipse can be controlled from the command line. Features and bundles can be installed or uninstalled without firing up the UI, saving precious minutes. We have added a customized script in the Scala IDE repository. Here’s a taste of it:

$ eclipse-director.sh uninstall
Eclipse installation dir is /Applications/eclipse-helios-210
Unnstalling..
Uninstalling org.scala-ide.sdt.feature.feature.group 2.1.0.nightly-2_10-201201110534-4c40dde.
!SESSION 2012-02-10 11:18:07.453
   [..]
Operation completed in 12919 ms.

By default, this installs the latest nightly build of the Helium builds, for the specified Scala version(2.9.2-SNAPSHOT or trunk). You can install a different version using --branch, or even install from a local repository (directory on disk) using install-local.

$ eclipse-director.sh --eclipse-dir /Applications/eclipse-helios-210 install 2.9.2-SNAPSHOT
Eclipse installation dir is /Applications/eclipse-helios-210
Installing 2.9.2-SNAPSHOT..
  [..]
Installing org.scala-ide.sdt.feature.feature.group 2.1.0.nightly-2_09-201202091714-4ffdd09.
Operation completed in 46198 ms.

You can specify the location of your Eclipse installation directory using --eclipse-dir.

Scala IDE Roadmap

Fri Jan 20 00:00:00 -0800 2012

After an exciting end of the year, concluded with the release of the Scala IDE V2.0 for Eclipse, it is now time to focus our efforts on the next Scala IDE’s release, code name Helium. During the past week we have prepared a tentative roadmap, which we would like to share with the community.

We will have three milestones, each of them containing both new functionalities and major redesign of the current plugin’s architecture. In fact, one important goal of the future release is to provide a clean and simple API to developers interested in building plugins on top of the Scala IDE.

Here follows the complete roadmap:

Milestone 1 - mid-March 2012

Implicit highlighting - Jin Mingjian, David Bernard and Mirko Stocker done
Semantic highlighting - Matt Russell
Move to Eclipse Indigo - Eric Molitor done
Design and implement a Scala model - Typesafe team
Create an abstraction layer with the Scala compiler - Typesafe team
Use the Scala model for the Outline view - Typesafe team
Smoother step over/in in the debugger - Typesafe team
Create a worksheet (like a REPL but in an editor) - Typesafe team
Create a new JDT model builder, using the compiled classes - Typesafe team
Extract the presentation compiler in its own project - Typesafe team

Milestone 2 - mid-May 2012

Add support for Find References - Typesafe team
Create a real Scala Editor (with all completion, indentation, formatting, … support) - Typesafe team
Improve dependency tracking - Typesafe team

Milestone 3 - mid-July 2012

Add support for Type Hierarchy (both in JDT and Scala specific) - Typesafe team
Scala Search (implicit use) - Typesafe team
Add support Call Hierarchy - Typesafe team
Finalize the API in Scala IDE - Typesafe team

Not aligned

More refactoring support - Mirko Stocker, Michael Holzer
Specs2 support - Eric Torreborre?
ScalaTest support - Bill Venners?

Items marked with done are already available in the nightly builds. If you like staying on the cutting edge, you can install the Scala IDE Helium through one of the update sites available in the Nightlies download page.

If you would like to contribute to the Scala IDE project, we believe this is the perfect time to get involved. Come and help us pushing the Scala IDE to the next level!

Release Notes 2.0

Tue Dec 20 00:00:00 -0800 2011

We released the Scala IDE V2.0 for Eclipse today! After 9 months of intensive work by the community contributors, users and the IDE team we are really proud to release the new version. Not only is it robust and reliable but also comes with much improved performance and responsiveness. There are a whole lot of new features that make it a real pleasure to use, Report errors as you type, Project builder with dependency tracking, Definition Hyperlinking and Inferred type hovers, Code completion and better integration with Java build tools, and lots more. You can learn more about them all below. We hope you will enjoy using the new version and continue to help us with ideas and improvement suggestions, or just contribute them.

While working on V2.0 the team has been listening hard to what the IDE users need. Simply stated faster compilation, better debugging and better integration with established Java tools like Maven. The good news is the team is ready for and excited by the challenge. Doing V2.0 we learned a lot about the build process and now understand what is needed to make significant gains in large project compile times. This and providing a solid debugging capability will be the main thrust of the next IDE development cycle. More details will be laid out as we go through the project planning phase and establish milestones. Contributors will be most welcome and we have made it a lot easier to be one. So if you want us to get the next version faster, come and help!

A lot of effort has gone into this version of the IDE and we would like to recognize the people who have contributed so much time and energy to the success of the project.

A bit of history

The Scala IDE project began a few years back, when Miles Sabin laid down the foundations of the open source project and an enthusiastic community formed around the effort to create a free, open-source, Eclipse-based IDE for Scala. In late 2010 the Typesafe team decided to support the open source project, and in September Eugene Vigdorchik became the first full-time engineer to work on the project, supported part-time by Hubert Plociniczak from the EPFL team. Typesafe founder and Scala creator Martin Odersky led the redesign of the Scala presentation compiler, the engine behind the IDE semantic actions.

Version 2.0

For version 2.0 we had some tough decisions to take, and development started with a very limited number of features, aiming for a very reliable core. Naturally, this raised the need for early and frequent feedback from our users: on March 28 we had the first beta of the upcoming 2.0 release. This was followed by a stream of betas (12 in total!), packing around 300 closed tickets over the next months. As Eugene moved on to other projects, several other Typesafe engineers joined the IDE team: Iulian Dragos and Mirco Dotta, followed by Luc Bourlier in September. Together with the great community (Mirko Stocker and Matt Russell just to name a few), the IDE took great strides to reach its first production-ready release.

Diversity

As things moved forward and the 2.0 branch became the main version in use, it became clear that we needed to have more than one IDE version: 2.0 remained the rock-solid branch, where only bug-fixing happens, while 2.1 is the place where new features, such as semantic highlighting or implicit highlighting are developed.

Besides the two IDE versions, we support three versions of the Scala compiler: 2.8.x, 2.9.x and 2.10 (Scala trunk), with nightlies for all of them, so you can choose what suits you the best: the latest IDE developments on a stable Scala compiler, the stable IDE on the bleeding edge Scala compiler, or even the latest and greatest of both – like the core Scala team, who uses the Eclipse IDE for their daily scalac development! The choice is yours.

Community

While the IDE always had a vibrant community around it, contributing to the project itself was sometimes challenging for newcomers. On October 4 we moved the project to Github, leading to a much simpler process for contributors. In just a few weeks we had 17 forks, some of which are extremely interesting developments in their own right (check out ScalaGWT, who brings Scala to the GWT framework).

Website

Today we also release a redesign of the Scala IDE website, along with reworked documentation, including screencasts. Thanks Heather for the awesome work (also, check out the screencasts)! We believe that the current version is not only pretty, but makes it much easier to find documentation, both for users and contributors (and everyone is a potential contributor!). The website is backed by Github too, so you can contribute by using the awesome Pull Request button!

A look at the future

Even though it’s been a long ride, today’s release is not the end of the road, but rather a beginning. We can now look at adding new features on a solid base, and great things will come, such as /find references/, or a Scala /debugger/. Suggest your favorite feature, and help us build the next great IDE!

After the 2.0.0 release we will continue to support the 2.0 branch with maintenance releases including important bug fixes. However, the focus will shift to the 2.1 development, and concentrate on the upcoming features. Also, 2.0.0 is the last version that supports the 2.8 compiler. This decision was not taken lightly, but the effort to support 2.8 is way too high and slowed us down too much. We believe that 2.0.0 is a solid release that can help people who cannot upgrade to 2.9.x in the immediate future.

Features

Scala IDE version 2 improves developer productivity through a large number of features. Below we highlight the main ones, but don’t forget to check out the full list on the website, and watch the screencast to see them in action.

Report errors as you type

The IDE saves you time by type-checking your program as you type, and notifying you of errors before you build. This greatly reduces the number of times you need to build your project.

Project builder with dependency tracking

The IDE saves you time even when you do have to build your project: by using Sbt’s engine for tracking dependencies between source files (even between dependent projects), the IDE only builds the sources that need to be built. This is often much less than all the sources in your project.

Definition Hyperlinking

Ctrl-click on an identifier to navigate to its definition. This allows you to concentrate on your program, since you don’t need to remember in what source file a certain definition lies. Try it out surfing through the Scala collection library!

Code Completion

Hit Ctrl-space to see a list of all members you could invoke at a certain point in your program. Even members added through implicit conversions are available. Moreover, you can find a class on your classpath, even if it wasn’t imported in your file yet (and the completion engine takes care of adding the import).

Inferred type hovers

Hover with the mouse over an identifier to see its type. This comes in handy when the compiler infers a different type than what you expect.

And there is more! Check out the full list of features, and download Scala IDE 2.0 today at www.scala-ide.org!