I stumbled across the ScalaCL project and its compiler plugin that has an awesome loop optimizer.
This made me wonder:
Which compiler plugins are available for scala?
Plugins need not be performance improving plugins; any type of plugin is eligible for this list.
(I have done Google searches but the SNR is low for this query.)
A few plugins are linked from this thread on the mailing list (autoproxy, browse, enhanced strings, avro).
From the Scala team, there is the existing delimited continuations plugin, and a current effort toward an effect system plugin.
Documentation on writing a plugin is here.
There also exists a compiler plugin for generation functional lenses in scalaz: https://github.com/gseitz/Lensed for more details see here: http://groups.google.com/group/scalaz/browse_thread/thread/a9334c5741b67d55
There's also the miniboxing plugin, for optimizing generics: scala-miniboxing.org.
Here's a plugin written by Eiríkr Åsheim that optimizes generic numeric code (runtime + compiler plugin) :
https://github.com/azavea/numeric
Related
I was wondering if anyone can explain where and how comment documentation in Scala is applicable - in particular, the Eclipse plugin. For example, is there a way to comment a procedure, that might later show as a help-hint while using Eclipse? I'm not entirely sure how to get these Javadoc like effects when using Scala Eclipse. I've checked the various FAQs for the plugin, it's possibly not supported but I can't find an explanation either way.
You need to use Scaladoc, but it isn't supported completely yet.
ScalaDoc on hover/completion is not yet integrated in the Scala IDE.
The good news is that this feature is currently under development and we plan to have intial support for it in the coming months. A Pull Request for adding ScalaDoc in support in the Scala Presentation Compiler has been recently merged.
A Pull Request on the Scala IDE project will follow. You can track progress on this feature here
I've been searching for a long time now to find a decent IDE for Scala.
Eclipse is not satisfying at all, as auto completion doesn't work, somehow. Also, I can't modify the libraries at all in the build path e.g. set the docs/source.
IntelliJ seems better, however, there are some major bugs:
When the drop down menu appears that lists all the function, some of them are sometimes just not shown! I think it's because of scala-library / scala-compiler, it mixes them up or something...
The docs cannot be fetched, I get this message over and over again (here the functions are listed, strange enough...):
This is the library window:
The dependencies and the compiler are set right, I strongly suppose.
Does anyone know what the problem is? And how to fix it? Or is it a known bug?
Is there an IDE that can handle Scala?
Regards!
Typically, searching for names (values/classes/functions/etc.) for auto-complete can be quite slow compared to Java in IntelliJ simply because the automatically imported namespace can be quite large, and it also searches through all implicit conversions. However, I've never seen it refuse to show functions like your screenshot, what version of IntelliJ and Scala plugin are you using?
I've never gotten the pop-up docs to work via attaching JavaDocs (I haven't tried remote fetching), so I'd recommend just ctrl+click to go through to the source to read the documentation there. (However, the function/type definition does popup correctly when sources are attached). I'd suggest posting an issue at http://youtrack.jetbrains.com/issues/SCL if you have the opportunity.
To your final question, the answer is unfortunately no. The tooling for Scala is nowhere near that of Java, but both Scala IDE for Eclipse and IntelliJ are making great progress in changing that, and both are strong in some areas while weak in others. In the end, you'll get limited support either way, so choose whichever fits you best.
I have found the solution to the problem:
The bug was caused by Java Decompiler Plugin. It tried to decompile the binaries of Scala's class-files, which obviously failed. This led to that error message and further led to the Scala plugin not working as it should, thus not displaying some of the functions.
This took me a long time to figure out, I installed 2 other versions of IntelliJ (which apparently imported the JD plugin), NetBeans and downloaded several builds of the Scala Plugin, only to discover this cause. Deactivating Java Decompiler solved it.
Regards.
Where I work, we use mostly Java. We've always made extensive use of CheckStyle to enforce our coding standards for Java.
We're now branching out into Scala. Many of the same considerations as in Java apply (indentation/whitespace, naming conventions, ...) - and arguably having a consistent coding style is even more important given the power of the language.
However, there does not seem to be a Checkstyle equivalent for Scala.
Does anyone know of one?
Yes. It is called Scalastyle. (Same sort of focus as Checkstyle and findbugs). It's currently in version 0.2.0, we're adding rules all of the time
EDIT (Dec 2012):
Scalastyle 0.2.0 was released last month, with a total of 46 rules. There is, in no particular order:
A maven plugin
An eclipse plugin
An SBT plugin
Under development are:
An Intellij plugin
A sonar plugin
Contributions/bug fixes are always welcome: github.
For code formatting, you can use Scalariform.
It can be used standalone, integrated into an editor, or as an SBT plugin that runs it automatically before every compilation.
Codacy integrates Scalastyle (amazing work from Matthew) along with custom rules (like checking for Option.get() and warning you when you do them) and works as an improved Sonar for Scala.
Free for open source.
You also have abide from the Typesafe team and scapegoat from the makers of SCoverage.
There's sniff, which detect "code smells" based on regular expressions. It can be used as a Specs2 test, which is nice.
The scala plugin seems to automatically download version 2.8 of Scala. I'l like to try out the Gridgain 3.0-beta, which currently only works with Scala 2.7.7. Since Gridgain 3.0-beta already provides scala-compiler-2.7.7.jar and scala-library-2.7.7.jar, is it possible to get the Eclipse Scala Plugin to compile to Scala 2.7.7?
I tried removing the Scala Library 2.8 from the project build path and added both the 2.7 jars, but this didn't seem to work.
Would this be easier if I switched to Netbeans?
Both the Eclipse plugin and the NetBeans plugin use the Scala Compiler for a lot of things from the simple stuff like syntax highlighting to stuff like type inference, resolution and display of implicits to more involved stuff like automated type-driven refactorings and semantic highlighting.
And more specifically, they use the 2.8 compiler, because the 2.8 compiler has a completely refactored API and a new framework (the so-called presentation compiler), which is specifically designed for IDEs, so that they can get all the information they need out of the compiler, but also can feed information (like in the case of refactorings) back into the compiler.
So, in short: the version of the plugin is closely coupled to the version of the compiler, and the compiler in turn only supports one version of the language. In particular, the IDE plugins require a 2.8 version of the compiler, because they use the new presentation compiler framework, and the 2.8 compiler does not support the 2.7 language.
This tight coupling is of course not a good thing, and it will get broken up in the future, but for now, you are stuck.
You could try the IntelliJ IDEA IDE and their Scala plugin. As far as I know, they have written their own compiler (well, at least the parts they need for syntax highlighting and refactoring purposes) purely from the Scala Language Specification, without using any of the Scala Compiler APIs. The Scala Plugin does work with the Community Edition.
The best place for questions like this is the Scala IDE user mailing list. But in brief, the Eclipse tooling for Scala doesn't support the use of other versions of the Scala compiler and libraries than the ones which it ships with. This is unlikely to change in the foreseeable future.
I've been reading up on Scala a lot recently and I really want to get into it. I do my Java web development from within Eclipse with Tomcat as my preferred server and I'd like to keep it that way. I've tried the Scala Eclipse plugin but it's safe to say, it isn't there yet. I had to uninstall it because it simply ins't working. On top of that, it doesn't seem to provide anything for doing web projects (I could be wrong there).
Since Scala is a compiled language just like Java is, I was wondering if it's possible to simply swap out Java with Scala, as in, where I'd normally would create Java classes I would now be able to create Scala classes instead? Maybe even mix Java and Scala?
Is there anyone out there who's been able to set up a decent Scala workflow in Eclipse for web development without the dreaded "official" Scala Eclipse Plugin?
PS: I've tried the Play framework (I think it recently added Scala support) but it simply isn't for me. I like my classes compiled and to use JSP's for my views.
You don't say anything about what version of the Scala IDE for Eclipse you were using, or what you tried to do to resolve your issues. I suggest that before changing your workflow you head over to http://groups.google.com/group/scala-ide-user and see if we can help you out.
Since Scala is a compiled language
just like Java is, I was wondering if
it's possible to simply swap out Java
with Scala, as in, where I'd normally
would create Java classes I would now
be able to create Scala classes
instead?
Yes, absolutely. That's one of Scala's big advantages over some other JVM languages.
Maybe even mix Java and Scala?
Yes, absolutely. That's one of Scala's big advantages over some other JVM languages.
Make sure you have familiarity with the Java and Scala collections libraries (and that you keep them straight -- if you're planning using advanced Scala features on Java collections, definitely use a Scala 2.8 release candidate). Also make sure you're faimilar with the #BeanProperty annotation -- it can simplify your Scala coding somewhat.
As Miles said, you should give us the version of Eclipse you are working with.
I'm also new to Scala and found difficult to work through Eclipse. I was using Eclipse Galileo 3.5.2 and found specially long to compile all the scala libraries. I switched to IntelliJ (IDEA 9.0.2) and I'm much more confortable now. I recomend trying it although it's more a personal matter.
Even so, I agree, the plugins are not there yet specially for web development. The great news is that you can use everything you have in Java and mix it with Scala. Since Scala is compiled to Java BitCode, they are totally compatible. See Combining Scala and Java.
When writing in Scala you always have (almost) all the Java libraries at your service plus anything you have created before. You will have to be carefull with the types (i.e. primitive types) but it normally works out very well.