Is the scala eclipse IDE stable enough? - eclipse

I use eclipse as my scala IDE. But It seems not so good. I can build my project using maven successfully. But eclipse always warn me there's compilation error. Any has experience of scala eclipse plugin ? Thanks BTW I use scala IDE for 2.8.1

There is a new Eclipse plug-in which is in the final stages of release, currently in beta 4 which offers numerous improvements including stability. It runs with Scala 2.9.
You can download and try it for yourself. More information and download available here:
http://www.scala-ide.org/
Also, be sure to read on improving Eclipse performance, I find a few of these tweaks makes a big difference. Here are some answers on Stackoverflow regarding that:
How can you speed up Eclipse?
What are the best JVM settings for Eclipse?

I've been using all three major IDEs over the last few days for Scala.
Eclipse is pretty good and perfectly useable although you will encounter a few bugs - silly things like you can't load compiler plugins if you have a space in your plugin folder pathname. It also behaved pretty badly a few times and wouldn't run anything until I restarted Eclipse, but this might be partly because I'm new to it and maybe have been doing something wrong. One thing that is good about Eclipse is that the build time is a lot quicker than for the other two - I think this is because it does and "incremental build". Or maybe it's just more optimized, but it's noticeable.
I would recommend trying the latest version of IntelliJ (10.5). It seems to be the best at the moment with the fewest rough edges, and the only one to have Scaladoc support integrated. I haven't used it much but first impressions are good.
The NetBeans plugin seems to be getting left behind a bit (there's only one guy working on it), which is a shame because it has IMO easily the best code editor for Java, with excellent predictive capabilities which you don't get for Scala at the moment. I'll continue to use it for Java, but the Scala plugin development is a bit sparse. (Although it might be because I'm using a beta version, because that's all that's available right now for Scala 2.9.)

Related

Scala plugin and Rational Developer for System z with Java not working

Hi all you clever people.
I'm a Scala enthusiast which fully believe in Scala as a tool which will raise productivity, compared to Java in many areas. I have been a happy user of the eclipse scala plugin for some time. However now the time has come for me to introduce it for my colleagues, and to my big disappointment the Scala plugin doesn't seem to work with Rational Developer for System z with Java.
This is a big issue for me, since I wouldn't like to force my colleagues to have another eclipse installation just for the Scala plugin, and when building.
The problems I get seems to be related to the java launcher, and also the aspectj weaving.
Is there somebody there know if this is a known issue, or what I else should do.
If nobody knows about this issue, I guess the next place to go, is to place a bug description on the Scala plugin, however I don't know the fix time for these kind of issues.
Many thanks in advance.
Regards Stefan
You're probably right in your analysis that it's something to do with the aspectj weaving. Does the Rational plugin use aspects at all? If so, that may be the problem. In the past there have been a number of problems due to the scala-ide use of aspects. There has been a lot of work done, and the latest versions (as of 15.03.2012) are a lot better.
Two things to try:
Try the latest version of the scala-ide plugin.
If the above doesn't work, raise a bug (http://www.assembla.com/spaces/scala-ide/tickets) but mention specifically that you're using Rational developer, and if you can identify the rational plugin that's using aspects, even better. Please attach a url which points to the version of the rational plugin that you're using.

Is it a good idea to develop an IDE for scala?

I have to choose a sizable (but not too sizable!) project for my next & last term in university. I thought maybe a nice IDE for scala is what the world might need right now :).
Would you like to see an IDE specifically made for scala? Or are you more comfortable using (the already available) plugins for popular (mainly java) IDEs & editors?
What do you think about the whole idea?
P.s. I'd make it open source & would add features one by one, so if it doesn't end in one semester, it won't be a problem from the university perspective.
Actually, not anymore. IntelliJ, Netbeans and Eclipse all have Scala-specific efforts that have more man-hours in it than you could possible start to begin putting in at a last term. And there's two very interesting efforts that were results of projects like that, both of which were made to contribute to any IDE effort: ENSIME and Scala Refactoring.
And, beyond these efforts, most programming editors, such as jEdit or TextMate, also have some Scala support to one degree or another.
So, really, contributing to one of these projects might be a good idea, but making a Scala IDE is not.
For his Masters thesis, Mirko Stocker contributed the refactoring functionality to the Eclipse Scala plugin, see:
http://misto.ch/scala-refactoring-talk-at-scala-days-2010/
Instead of creating an IDE from scratch, why not contribute a major piece of functionality to the Eclipse plugin, all contributions are welcome. For ideas, see tickets.
Or instead of reinventing the wheel.. you can contribute..
http://wiki.netbeans.org/Scala
But I am not sure if it will be somehow enough for your university work. At the same time, as you see, those plug-ins still require a lot of work.
While writing your own IDE you will just trying to solve problems that were already solved and tested. Besides, even if - what kind of IDE is that, which allows you to do
Scala (even if its great) only. So just for simple xml edit of ant file or whatever you will need another tool.
I think Brian Clapper already summed it up nicely.
I'd suggest something like CheckStyle but for Scala might go down well and be reasonable to tackle as a project.
Not a Scala developer but an Eclipse plug-in would probably be a worthy senior project.
Concur. Operating systems, text editors, and IDEs...does the world really need more of them? No. But everyone wants to write one.
If you want to do something useful, as opposed to simply academic, develop an extension for an existing IDE. Eclipse, NetBeans, Komodo, etc. are all nicely extensible through plugins.

Another Java vs. Scala perspective - is this typical?

I have been reading about Scala for a while and even wrote some small programs to better understand some of the more exoteric features.
Today I decided to do my first "real project", translating some 60 lines of ugly Java code to Scala to rewrite it using the better pattern-matching features (why? because the Java version was becoming hard to maintain due to excessive combination of regex and conditionals).
About halfway through the editing process, Eclipse thew up this error:
alt text http://img269.imageshack.us/img269/1243/errorms.jpg
I get the general impression that the Scala IDE in Eclipse is a lot buggier and less complete than its Java equivalent. Is this correct or do I just have a bad installation? Is there a better IDE for Scala?
I really like IntelliJ Idea Community Edition's Scala support. I've been using it from it's early days. I've also tested Netbeans and Eclipse plugins but I really don't like them that much. Especially all Eclipse Scala plugins are crap. I also tested Textmate Scala bundle, which is very nice but doesn't offer auto completion.
Here is my Scala Ide top list:
IntelliJ Idea Community Edition
Netbeans
Textmate (This is here, since I really like Textmate for writing Rails applications)
Eclipse
When you learn IntelliJ Idea keyboard shortcuts and add some live templates you can be very productive programmer. Furthermore, if you buy the Intellij Idea Ultimate Edition you can even share the settings with multiple computers or with your team.
What I suggest:
Download IntelliJ Idea Community Edition
Install the Scala plugin
Learn the keyboard shortcuts: Windows and Linux, Mac
Configure Live Templates when you get more familiar with the ide
The Eclipse IDE Scala support has not been great for some time, but is now receiving additional development effort alongside the introduction of Scala 2.8, and appears to be improving. For Scala 2.7 I have found the Intellij plugin to be in a better state.
One problem that both of these plugins have is that Scala itself is a moving target - Scala 2.8 has introduced additional syntax and structures to Scala 2.7.
From my own experience with Eclipse, using it for languages other than Java is never quite as good.
You might find this post of interest.
I get the general impression an IDE for a new, young, niche language is a lot buggier and less complete than a widespread, supported, mature language
Try Netbeans. Its plugins are generally of a simpler construction anyway, so should have less 'gotchas'
One point to make is that it is possible that people are still put off IntelliJ because they assume that the licence is expensive, especially if they are happy with Eclipse and are unaware of the Community Edition which is free and open source.
I cannot give any comparison with the other IDEs as I have always used IntelliJ, however the Scala support is certainly good, all things considered, and getting better.
We are using Eclipse Scala plugin at work and working with it is quite terrible. One cannot really trust reported errors inside IDE, runtime exceptions are the order of the day. Our best experience is with build from 25-11-2009.
At home I play with IntelliJ 9 and its Scala plugin and I find it much much better. I am newbie to IntelliJ but I am very impressed with all those little details which (once you get used to them) increase your productivity... a lot.
The drawback is in IntelliJ there is no compile-error reporting on the fly (at the time you're writing code) yet implemented and only Scala up to 2.7 is supported (2.8 by nightly builds only), but there are NO runtime exceptions while working with the IDE. I would recommend you to try IntelliJ, community edition at least.
I never really get on with IDEs at the best of times because they are usually pretty awful at actual text editing, but Eclipse's Scala plugin is particularly brittle to the point that projects "forget" that they are Scala after a while. Battling Eclipse seems to consume more effort than it saves. I just went back to my Emacs and sbt REPL in a terminal.
A light play with IntelliJ confirmed that it does at least do the job as a Scala IDE, but again I didn't care for its editor. It's also commercial software. However, if you are seeking a robust Scala IDE, this is perhaps where you should be looking.
What I have since settled on is perhaps perverse and not for the newcomer, but suits somebody who has definite opinions about their text editor. ENSIME is an editor plugin and server component that adds what you need from a Scala IDE to Emacs. It also claims support for vim, Atom, and Sublime, but I've not tested these. Occasionally it also has a bad day—obscure kinds of macros particularly confuddle it—but it generally does the job.

How to become more productive using Scala? (Tools, IDEs)

What Tools do you people use to work with Scala? For my learning phase, I used the Scala REPL and hacked some code with TextMate and compiled it with the scalac CLI. But as the projects grow in size, much more sophisticated tools are required.
I am aware of the Scala plugins for Elipse, IntelliJ and Netbeans and I tried them all. The best one is IMHO IntelliJ, but still far away from being perfect.
The major issue I have is the lack of auto completion. As a not-so-advanced Scala coder, I still dont know the whole standard API and have to switch between the Scaladoc and IDE regularly. This feels like "killing productivity". But they all fail to auto-complete method arguments. (I heard that method arguments are not included in compiled scala code, but what about attaching source to do auto completion?)
Another very annoying issue is the build process. I am using Maven to build my Scala projects and manage their dependencies. But nevertheless, I have to do a full rebuild to test my changes. Maybe I am spoiled by Eclipses incremental rebuild available in the Java world, but it feels like a big issue to me.
I like Scala very much and I feel way more productive while coding, but the lack of sophisticed tools let me feel less productive. And both seem to cancel out themselves.
So, whats my question? I doubt every single Scala programmer uses good ol' vim or emacs along with scalac to do their work. So what tools do you use? What workflows have you developed to bring speed into developing with the Scala language?
Edit
Clarification what I ment with auto-completion of method arguments.
val myList = "foo" :: "all your base" :: Nil
myList.partition(_.length > 3)
For the code above, IntelliJ fail to provide me with the information that partition requires that I have to pass a () => Boolean function. In fact, IntelliJ does not check for this contraint. I can pass a String and IntelliJ will not indicate my error until I do a compile.
scalac
Get familiar with command line options to Scalac.
-deprecation
-Xprint:all: watch your code progress through compiler phases, very useful to see what implicits are applied.
-help / -X' /-Y` list all options.
The latest nightly builds of scalac include a bash completion file that makes these easier to use.
IntelliJ IDEA
Method completion with Javadoc (CTRL-Space, CTRL-Q/Apple-J) Screenshot
Parameter Info for the example in the question (CTRL-P) Screenshot
Method Argument Completion (CTRL-SHIFT-Space). Screenshot
You need to have the source or javadocs linked into the dependencies in IntelliJ to see the Javadoc.
It doesn't currently highlight type errors on the fly, as there are still too many false-positives in complex code. This is coming, though.
Simple Build Tool
SBT keeps the compiler resident, and analyzes dependencies between classes to allow incremental recompilation. It can also monitor for changes to source files and automatically trigger recompilation and/or test execution.
Continous Compilation: >~compile
Continuous Compilation + Test: ~test-quick
I have SBT and IntelliJ project configured in http://github.com/scalaz/scalaz, you could use this as a reference.
I've been using Scala daily for the last six months. I'm still using vim (and ctags to find stuff), and Maven for builds. I've gotten some good mileage out of JRebel when working on Lift web apps -- it will reload changes on the fly without server restarts.
I spent some time looking into IDEs, but it got depressing really fast. I really missed a lot of Eclipse features at first, but after a period of adjustment I don't think I'm significantly less productive now.
I've heard some rumblings that NetBeans is the current champ for Scala IDEs, but I haven't tried it first hand.
One simple way is to use fsc, an offline compiler. It maintains caches of information, and the standard compiler will talk to fsc (running as a daemon) and use its cached information during compilation, thus speeding up your compilation cycle.
Here's my answer on a similar thread. After giving about an hour to Ensime. I just can't help but get the word out. I must say it's very, very well written for an Emacs package.
I am afraid you have to wait for Scala to become rock-solid.
I had exactly the same issue with Java ten years ago. It was even worse.
I also tried them all. For Scala 2.7.7 IntelliJ is the winner, but for Scala 2.8.0-SNAPSHOT Eclipse is not that bad.
Wait half of a year after 2.8.0 is released and check again. It should become bearable.
With Scala 2.8, please see this for getting better performance out of Maven.
You should also give Netbeans 6.8 a try with the nightly Scala build. I am very satisfied programming Scala with this IDE. For building, I sometimes also use Ant. The best thing about NB Scala plugin is that it is fast and code-completion works flawlessly.
For the example you gave: NB gives me this error
code-completion:
The Eclipse Scala IDE is quite mature now (as of 3.0).

What's the best Scala build system? [closed]

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I've seen questions about IDE's here -- Which is the best IDE for Scala development? and What is the current state of tooling for Scala?, but I've had mixed experiences with IDEs. Right now, I'm using the Eclipse IDE with the automatic workspace refresh option, and KDE 4's Kate as my text editor. Here are some of the problems I'd like to solve:
use my own editor IDEs are really geared at everyone using their components. I like Kate better, but the refresh system is very annoying (it doesn't use inotify, rather, maybe a 10s polling interval). The reason I don't use the built-in text editor is because broken auto-complete functionalities cause the IDE to hang for maybe 10s.
rebuild only modified files The Eclipse build system is broken. It doesn't know when to rebuild classes. I find myself almost half of the time going to project->clean. Worse, it seems even after it has finished building my project, a few minutes later it will pop up with some bizarre error (edit - these errors appear to be things that were previously solved with a project > clean, but then come back up...). Finally, setting "Preferences / Continue launch if project contains errors" to "prompt" seems to have no effect for Scala projects (i.e. it always launches even if there are errors).
build customization I can use the "nightly" release, but I'll want to modify and use my own Scala builds, not the compiler that's built into the IDE's plugin. It would also be nice to pass [e.g.] -Xprint:jvm to the compiler (to print out lowered code).
fast compiling Though Eclipse doesn't always build right, it does seem snappy -- even more so than fsc.
I looked at Ant and Maven, though haven't employed either yet (I'll also need to spend time solving #3 and #4). I wanted to see if anyone has other suggestions before I spend time getting a suboptimal build system working. Thanks in advance!
UPDATE - I'm now using Maven, passing a project as a compiler plugin to it. It seems fast enough; I'm not sure what kind of jar caching Maven does. A current repository for Scala 2.8.0 is available [link]. The archetypes are very cool, and cross-platform support seems very good. However, about compile issues, I'm not sure if fsc is actually fixed, or my project is stable enough (e.g. class names aren't changing) -- running it manually doesn't bother me as much. If you'd like to see an example, feel free to browse the pom.xml files I'm using [github].
UPDATE 2 - from benchmarks I've seen, Daniel Spiewak is right that buildr's faster than Maven (and, if one is doing incremental changes, Maven's 10 second latency gets annoying), so if one can craft a compatible build file, then it's probably worth it...
Points 2 and 4 are extremely difficult to manage with the current scalac. The problem is that Scala's compiler is a little dumb about building files. Basically, it will build whatever you feed it, regardless of whether or not that file really needs to be built. Scala 2.8.0 will have some tremendous improvements in this respect, but until then... Eclipse SDT actually has some very elaborate (and very hackish) code for doing change detection and dependency tracking. On the whole, it does a decent job, but as you have seen, there are wrinkles. Eclipse SDT 2.8.0 will rely on the aforementioned improvements to scalac itself.
So, building only modified files is pretty much out of the question. Aside from SDT, the only tool I know of which even tries this is SBT (Simple Build Tool). It uses a compiler plugin to track files as they are compiled and query the dependency graph computed by the compiler itself. In practice, this yields about a 50% improvement over the recompile-the-world approach. Once again, this is a hack to get around deficiencies in pre-2.8.0 scalac.
The good news is that reasonably fast compilation is still achievable even without worrying about change detection. FSC uses the same technology (ooh, that sounded so "Charlie Eppes") that Eclipse SDT uses to implement fast incremental compilation. In short, it's pretty snappy.
Personally, I use Apache Buildr. Its configuration is significantly cleaner than either Maven's or SBT's and its startup time is orders of magnitude less (when running under MRI). It integrates with FSC and attempts to do some basic change detection on its own (fairly primitive). It also has auto-magical support for the major Scala test frameworks (ScalaTest, ScalaCheck and Specs) as well as support for joint compilation with Java sources and IDE meta generation for IntelliJ and Eclipse. Oh, and it supports all of Maven's features (dependency resolution, etc) and then some. I'm even working on an extension which would allow interactive shell support integrated with JavaRebel and supporting several shell providers (Scala, JIRB, Clojure REPL, etc). It's not ready for the SVN yet, but I'll commit once it's ready (possibly in time for 1.3.5).
As you can see, I'm very firmly of the opinion that Buildr is the best Scala build tool out there. Its documentation is a little spotty where Scala is concerned, but that's because everything is so straightforward that it's hard to document without feeling verbose. You can always check out one of my GitHub repositories for examples. Good luck!
Have you looked at Intellij IDEA and its Scala integration ? Intellij has a loyal (fanatical?) following amongst Java developers, so you may find this is appropriate for your needs.
Am also quite frustrated with the scala plugin on Eclipse and I can add a few more problems to the list:
auto-complete only works some of the time
the debugger doesn't work properly (especially when trying to debug scala xml)
the debugger forgets breakpoints
'go to definition' doesn't work more often than not.
I'm glad to hear that Buildr sounds like a better alternative (on the build front anyhow), I'll give that a try - thanks!
If you use Emacs, I think Ensime is a pretty good IDE. I think at the time writing, Ensime is the only IDE that will give you fast and accurate autocompletion on both Scala and Java objects, including implicit conversions.
There's code browsing support using Speedbar, code templates using the excellent Yasnippet, and code completion menu using Autocomplete. These are all very modern, actively maintained Emacs packages. There's also out of the box incremental building support for Maven and SBT.
There's a lot more in there such as interactive debugging, refactoring, and the Scala interpreter in an inferior process. All the things you want in a modern IDE for Scala is already there in Ensime. Highly recommended for Emacsens.
For the reasons of completeness, I have to say that there is also Pants -- the build tool that in use in Twitter (one of the early scala adopters)
The main difference it that it is intended not only for scala (and written in python, by the way) and is modeled after google build system.
It's not so bloated as sbt, so for the freshmans it's much simplier, but I've never heard about Pants usage outside of twitter and foursquare.
If you scared of SBT, maybe another no-so-popular build tool, ABT, could be an alternative for you?
I went down the same road, and here is where I am at:
- After some initial investigation, I dropped Kate. I love to use it for most things, but when it came to things like defining tab completions, I found it sorely lacking. I would recommend that you look into gedit instead, which is much more robust for Scala development
- With gedit as my editor, I use SBT and have found it to be a great build tool. I can put it into a 'test' mode where when any code changes it recompiles the relevant files and runs my test suite. This has been an extremely effective way to work.
I have not taken a look at Buildr yet. I would like to say that I will, but honestly with SBT at my disposal I don't really have a compelling need to look at another build tool.
If you want to use Eclipse, but build the project using sbt, and still be able to debug, take a look at this post here:
zikaprog.wordpress.com/2010/04/19/scala-eclipse-sbt-and-debugging/
It also can be applied to builders other than sbt.
The latest version of the Maven Scala plugin supports Zinc/Nailgun for faster start times and faster incremental builds. See Zinc and Incremental Compilation.