I have recently begun exploring Scala, and have started by installing the Scala IDE in my copy of Eclipse (Indigo). I initially installed the Scala IDE for Scala 2.9, but then noticed that there was a newer release available for Scala 2.10. Installing the newer plug-in over the older one seems to have worked, but...
Scala 2.10 has deprecated the older Scala Actors in favor of Akka Actors. Thus I'm trying to add an import to my toy Scala project:
import akka.actor.Actor
This is flagged in the IDE with the error
not found: object akka
When I look at my Scala project's properties, I indeed do not see any of the akka-* jar files that are mentioned in the Akka documentation.
Do they need to be downloaded and installed separately, even though the Scala IDE plug-in installed the rest of Scala 2.10? Or have package names changed as part of integrating Akka actors in place of the older Scala Actors? (The documentation doesn't say so, but the Scala 2.10 release is fairly recent...)
No, they aren't packaged together.
The easiest way to make sure the Eclipse IDE can see your dependencies (Akka, and anything else referenced in your build.sbt file) is to let sbt do it using the sbteclipse plugin. Here's the instructions I wrote up for co-workers:
Install the "sbteclipse" plugin
This plugin will allow sbt to add the files/references that Eclipse needs to find all the dependencies that you specify in your build.sbt. Otherwise, you will be able to use the IDE, but you will seek all kinds of "object not found" errors.
Just make sure the plugin is being added in your global plugins.sbt file. This file (and it's path) may not exist so you may need to create it at the following location:
~/.sbt $ cd ~/.sbt/0.13/
~/.sbt/0.13 $ mkdir plugins
Edit/create the plugins.sbt file:
~/.sbt/0.13 $ vi plugins/plugins.sbt
then add this line (it may be the only line in the file):
addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "2.5.0")
Running sbteclipse
To use this, you just navigate to a scala project on the commandline and run the following. If you already had Eclipse open, go ahead and restart it.
/sites/ewuser (master)$ sbt eclipse
References:
How to initialize a new Scala project in sbt, Eclipse and github
Official sbteclipse plugin
The Akka artifacts are not bundled with the Scala IDE (yet), you will have to add “akka-actor_2.10” and friends to your project’s dependencies.
Download the akka for eclipse from below location
http://downloads.typesafe.com/akka/akka_2.11-2.4.1.zip?_ga=1.167921254.618585520.1450199987
extract the zip
add dependencies from the lib folder into project
Related
As shown in the picture, when I build scala project with sbteclipse and import to eclipse, when changing build.sbt , jars are downloaded to my computer but not to scalaProject. I do not know why. Can someone help me?
scala version: 2.11.8
sbt version: 0.13.15
stbeclipse:5.1.0
I assume that you're using the Scala IDE plugin for Eclipse, correct?
The sbteclipse SBT plugin merely provides a command to generate an Eclipse Scala project from the SBT build. Before using Eclipse, you're supposed to issue the following command (from the command line) to SBT:
sbt eclipse
This should generate the project files for your Eclipse project. After executing this command, you can open your project using Eclipse (with the Scala IDE plugin).
Note that, at present, the Scala IDE Eclipse plugin does not support SBT build files. That is, if you change your SBT build file, then Eclipse will be none the wiser, until you re-run the above command.
You might want to consider switching to IntelliJ IDEA (instead of Eclipse) which has a full-featured Scala plugin that fully supports SBT builds, including downloading any dependencies. For my money (both IDEs are free) IntelliJ is light-years ahead of Eclipse for Scala development.
I have been using sbt on windows and a custom build.sbt script in conjunction with an import Chisel._ in the top-level file in order to generate Verilog from my Chisel source successfully.
I'm trying to get an IDE working on Windows to expedite Chisel development. I've gone with the Eclipse based SCALA IDE http://scala-ide.org/download/sdk.html/
I want to compile the Chisel library so that the import Chisel._ can be resolved locally, without having to go off and download the source from the repository each timeand recompile the source. When I download the Chisel-master repo from Git and include the src\main folder in my SCALA project in the SCALA IDE, I get lots of syntax errors in the Chisel SCALA files that prevent me from building the project.
Has anyone done anything like this before on Windows or have any knowledge of working with the SCALA IDE as it may just be a case of undefined symbols in the project configuration?
Not sure exactly what you did with build.sbt respect to recompile (I think it download it only the first time, then it caches it for the future). But I'm using ScalaIDE for Chisel on linux, using the default build.sbt files, maybe you can try to get it working out of the box first to help narrow down the issue.
Here are the steps I took in order to get ScalaIDE work with Chisel:
the latest Scala IDE uses 2.11.8, the current Chisel repository defaults to 2.11.7. So I had to change all the build.sbt reference to scalaVersion from 2.11.7 to 2.11.8
I used sbteclipse
https://github.com/typesafehub/sbteclipse
To create importable the workspace to setup the compilation dependencies.
Except for chiselFrontEnd. For some reason, this package is not added to the dependency. I have to Add chiselFrontEnd as a javabuildpath dependency manually (Properties/JavaBuildPath, under Projects) for my own projects.
To resolve undefined symbols, you can also add a JAR onto the project build path using Project Properties > Java Build Path > Libraries > Add External JARs...
If you are getting your JARs through Maven / SBT, they should be in:
C:\Users\<name>\.ivy2\local\edu.berkeley.cs\chisel3_2.11\jars
If you are using publish-local with chisel3, your JARs should be in
C:\Users\<name>\.ivy2\cache\edu.berkeley.cs\chisel3_2.11\jars
Note that chisel3 is compiled into one JAR, including coreMacros and chiselFrontend sub-projects
Of course, this is a more quick-and-dirty solution compared to something that can parse SBT files.
I have some main object:
import org.apache.spark.SparkConf
import org.apache.spark.SparkContext
import org.apache.spark.SparkContext._
object Main {
def main(args: Array[String]) {
val sc = new SparkContext(
new SparkConf().setMaster("local").setAppName("FakeProjectName")
)
}
}
...then I add spark-assembly-1.3.0-hadoop2.4.0.jar to the build path in Eclipse from
Project > Properties... > Java Build Path :
...and this warning appears in the Eclipse console:
More than one scala library found in the build path
(C:/Program Files/Eclipse/Indigo 3.7.2/configuration/org.eclipse.osgi/bundles/246/1/.cp/lib/scala-library.jar,
C:/spark/lib/spark-assembly-1.3.0-hadoop2.4.0.jar).
This is not an optimal configuration, try to limit to one Scala library in the build path.
FakeProjectName Unknown Scala Classpath Problem
Then I remove Scala Library [2.10.2] from the build path, and it still works. Except now this warning appears in the Eclipse console:
The version of scala library found in the build path is different from the one provided by scala IDE:
2.10.4. Expected: 2.10.2. Make sure you know what you are doing.
FakeProjectName Unknown Scala Classpath Problem
Is this a non-issue? Either way, how do I fix it?
This is often a non-issue, especially when the version difference is small, but there are no guarantees...
The problem is (as stated in the warning) that your project has two Scala libraries on the class path. One is explicitly configured as part of the project; this is version 2.10.2 and is shipped with the Scala IDE plugins. The other copy has version 2.10.4 and is included in the Spark jar.
One way to fix the problem is to install a different version of Scala IDE, that ships with 2.10.4. But this is not ideal. As noted here, Scala IDE requires every project to use the same library version:
http://scala-ide.org/docs/current-user-doc/gettingstarted/index.html#choosing-what-version-to-install
A better solution is to clean up the class path by replacing the Spark jar you are using. The one you have is an assembly jar, which means it includes every dependency used in the build that produced it. If you are using sbt or Maven, then you can remove the assembly jar and simply add Spark 1.3.0 and Hadoop 2.4.0 as dependencies of your project. Every other dependency will be pulled in during your build. If you're not using sbt or Maven yet, then perhaps give sbt a spin - it is really easy to set up a build.sbt file with a couple of library dependencies, and sbt has a degree of support for specifying which library version to use.
The easiest solution:
In Eclipse :
1. Project/ (righclick) Properties
2. Go to Scala Compiler
3. click Use Project Settings
4. set Scala Installation to a compatible version. Generally Fixed Scala Installation 2.XX.X (build-in)
5. Rebuild the project.
There are 2 types of Spark JAR files (just by looking at the Name):
- Name includes the word "assembly" and not "core" (has Scala inside)
- Name includes the word "core" and not "assembly" (no Scala inside).
You should include the "core" type in your Build Path via “Add External Jars”
(the version you need) since the Scala IDE already shoves one Scala for you.
Alternatively, you can just take advantage of the SBT and add the following
Dependency (again, pay attention to the versions you need):
libraryDependencies += "org.apache.spark" % "spark-core_2.11" % "2.1.0"
Then you should NOT include “forcefully” any spark JAR in the Build Path.
Happy sparking:
Zar
>
Reason I ask, is because it's possible to specify a Scala version in the build.sbt file (using scalaVersion setting), and once you do that, sbt will automatically download that Scala version to use with the project.
I also seem to remember that despite having Scala 2.11.1 on my system, sbt would compile and run with Scala 2.10 if no version was specified.
So the question is, do I need to install Scala separately if I got sbt installed?
No you don't need it. sbt will download Scala for you.
If you install sbt-extras (basically just a script) you don't even need to download sbt: it will automatically download the sbt launcher you need. Very handy since you just need to specify sbt.version in your build.properties and you're good to go.
Edit: removed my comment about not being able to do sbt console in an empty directory, since both sbt and sbt-extras support it now.
I just got started with Scala/LiftWeb/Sbt developing, and I'd like to import a Sbt project in IntelliJ Idea.
Actually, I managed to import my project in two different ways:
1) with Maven. I created a Maven project, and of top of that I created a Sbt project, which I then imported in IntelliJ. I could then easily start, stop the jetty server, and do other stuff.
But that's not what I want. I want to do the same stuff, just Maven-free.
That lead me to
2) with Eclipse. So, I created a new Sbt project (with a little script I wrote, configuring the Sbt project to be a WebProject). I used then the sbt-eclipsify plugin to 'convert' the project for Eclipse, which I then imported in IntelliJ (existing source -> eclipse).
But the problems started here: I cannot get the IntelliJ Sbt plugin to work.
Can anyone help me with this?
There are three basic ways how to create a project - modern versions of IntelliJ can import sbt project out of the box, otherwise you can either use sbt plugin to generate IntelliJ project, or use IntelliJ Scala plugin to create sbt project. Basic features work out of the box using both solutions, some complex builds can have problems, so try other tools to see if it works there.
IntelliJ
IntelliJ IDEA has become so much better these days. The current version (14.0.2) supports sbt projects out of the box with the Scala plugin. Just install the plugin and you should be able to open up Scala/sbt projects without any troubles.
With the plugin, just point at a sbt project and IDEA is going to offer you a wizard to open that kind of project.
IntelliJ Scala Plugin
IntelliJ plugin can be found here
http://confluence.jetbrains.com/display/SCA/Scala+Plugin+for+IntelliJ+IDEA or can be installed directoly from within the IDE using Settings -> Plugins dialog. Afterwards one can just do File -> New Project -> Scala -> SBT based. IntelliJ will generate basic build.sbt, download necessary dependencies and open project.
SBT Plugin
Sbt plugin that generate an idea project based on the sbt files can be found here: https://github.com/mpeltonen/sbt-idea
SBT 12.0+ & 13.0+
Simply add addSbtPlugin("com.github.mpeltonen" % "sbt-idea" % "1.5.2") to your build.sbt; no additional resolvers are needed.
Older Versions:
SBT 0.11+
Create and add the following lines to ~/.sbt/plugins/build.sbt OR PROJECT_DIR/project/plugins.sbt
resolvers += "sbt-idea-repo" at "http://mpeltonen.github.com/maven/"
addSbtPlugin("com.github.mpeltonen" % "sbt-idea" % "1.6.0")
Use gen-idea in sbt to create IDEA project files.
By default, classifiers (i.e. sources and javadocs) of sbt and library dependencies are loaded if found and references added to IDEA project files. If you don't want to download/reference them, use command gen-idea no-classifiers no-sbt-classifiers.
SBT 0.10.1
(according to the plugin author, 0.10.0 won't work!)
Create and add the following lines to ~/.sbt/plugins/build.sbt:
resolvers += "sbt-idea-repo" at "http://mpeltonen.github.com/maven/"
libraryDependencies += "com.github.mpeltonen" %% "sbt-idea" % "0.10.0"
Use gen-idea sbt task to create IDEA project files.
By default, classifiers (i.e. sources and javadocs) of sbt and library dependencies are loaded if found and references added to IDEA project files. If you don't want to download/reference them, use command gen-idea no-classifiers no-sbt-classifiers.
SBT 0.7
To use it, simply run this from your sbt shell, it will use the plugin as an external program:
> *sbtIdeaRepo at http://mpeltonen.github.com/maven/
> *idea is com.github.mpeltonen sbt-idea-processor 0.4.0
...
> update
...
> idea
...
You can also add trait in your project definition, as you want:
import sbt._
class MyProject(info: ProjectInfo) extends ParentProject(info) with IdeaProject {
lazy val mySubProject = project("my-subproject", "my-subproject", new DefaultProject(_) with IdeaProject)
// ...
}
For now I do this by hand. It is quite simple.
Create the project with SBT
Create a new IDEA Project with the same root path
Create a module with the same root path
Set src/main/scala as a src path on the module
Set src/test/scala as a test path on the module
Add scala-library.jar as a library
Add lib (if it is present) as a jar directory within a module library
Add lib_managed/compile (if it is present) as a jar directory within a module library
Add lib_managed/test (if it is present) as a jar directory within a module library
That's it from memory. It would be better if it were automated, but it's no big deal as it is now.
One note of caution: The above approach doesn't work well with new-school sbt, i.e. versions 0.10 and newer, because it doesn't copy dependencies into lib_managed by default. You can add
retrieveManaged := true
to your build.sbt to make it copy the dependencies into lib_managed.
Tempus fugit and IntelliJ IDEA has become so much better these days. It's 2015 after all, isn't it?
Having said that, the latest version of IntelliJ IDEA 14.0.2 supports sbt projects out of the box with the Scala plugin. Just install the plugin and you should be able to open up Scala/sbt projects without much troubles.
I'm using the Early Access version of the plugin which is 1.2.67.6.EAP as of the time of the writing.
With the plugin just point at a sbt project and IDEA is going to offer you a wizard to open that kind of project.
About sbt-idea in sbt 0.12.4
For sbt 0.12.4 the system-wide plugin configuration file - ~/.sbt/plugins/build.sbt or PROJECT_DIR/project/plugins.sbt - should have the following lines:
resolvers += "Sonatype snapshots" at "http://oss.sonatype.org/content/repositories/snapshots/"
addSbtPlugin(dependency="com.github.mpeltonen" % "sbt-idea" % "1.5.0-SNAPSHOT")
Run sbt gen-idea to generate IDEA project files.
Read the sbt-idea plugin website for more up-to-date information. You may also find my blog entry Importing sbt-based project to IntelliJ IDEA 13 (with sbt-idea, Scala 2.11 and sbt 0.12) useful.
For sbt 0.7
See the answer elsewhere on this page.
For sbt 0.10
Clone and build Ismael's sbt-idea:
git clone https://github.com/ijuma/sbt-idea.git
cd sbt-idea
git checkout sbt-0.10
./sbt package
Create an sbt plugin lib directory if you don't have one already
mkdir -p ~/.sbt/plugins/lib
Copy the jar built in step one into here
cp sbt-idea/target/scala-2.8.1.final/*.jar ~/.sbt/plugins/lib
Restart or reload sbt, then you can run gen-idea (or gen-idea with-classifiers if you want sources and javadoc in intelliJ too)
Source: Tackers' suggestion on the message group.
In IntelliJ IDEA 13.x itself
You can open an SBT-based project in IDEA nowadays. It will create the necessary project and modules, and keep your dependencies up-to-date whenever you make changes to the build scripts.
I just went through all this pain. I spend days trying to get an acceptable environment up and have come to the conclusion that ENSIME, SBT and JRebel are going to be my development environment for some time. Yes, it is going back to Emacs, but ENSIME turns it into a bit or an idea with refactoring, debugging support, navigation, etc. It's not nowhere near as good as Eclipse (Java), but unless the scala plugins work better it's the best we have.
Until the Scala development environments get up to snuff (Eclipse or IntelliJ) I'm not going to bother. They're just way too buggy.
See the discussion on the lift site.
http://groups.google.com/group/liftweb/browse_thread/thread/6e38ae7396575052#
Within that thread, there is a link to a HOWTO for IntelliJ, but although it kinda works, there are many issues that render it a little less that useful.
http://blog.morroni.com/2010/07/14/setup-intellij-9-for-lift-framework-development/comment-page-1/
The answers are old for 2014.
In IntelliJ 13.x, the plugin Scala is ver 0.41.2 ( SBT is included).
My SBT version is 0.13.5 (terminal : sbt sbtVersion )
Go to the project's root folder and enter in the terminal
sbt idea
You will see two new hidden folders .idea and .idea_modules.
Then in IntelliJ, File > Open > select the project.
It should open the project without any problem.
Before you start creating your SBT project, make sure that the Scala plugin is downloaded and enabled in IntelliJ IDEA.
below link explains everything you need to know.
https://www.jetbrains.com/help/idea/2016.1/getting-started-with-sbt.html