I am trying to compile a (Scala) macro in Eclipse 3.7.2 with the Scala IDE Plugin available for Scala 2.10.0-M3, but I am experiencing the following error:
"macro implementation not found: XXXXX (the most common reason for that is that you cannot use macro implementations in the same compilation run that defines them) if you do need to define macro implementations along with the rest of your program, consider two-phase compilation with -Xmacro-fallback-classpath in the second phase pointing to the output of the first phase"
I already know how to avoid it with a simple editor and a terminal (just following the error message), but is it possible to achieve the dual phase task in Eclipse?
How to create a macro project to link to an existing project:
Create a scala project named for example ProjectMacros, put a file named for example Macros.scala containing macros in it. This project should compile without problems, because there are only macros.
Right-click on the existing scala project, then "Properties". The Properties window opens.
In the Java Build Path section:
Under the tab Projects, add ProjectMacros.
Under the tab Libraries, click Add Class Folder, and select the ProjectMacros/bin directory.
In the Project References section, check ProjectMacros
Now, after adding in the existing project an import like import Macros._ you can use the macros functions and annotations.
Well, separating macro implementation and macro invocation in two differents projects (and playing with project references) seems to solve the issue. Anyway, the Scala-IDE plugin has been notably improved with its version for Scala 2.10-M4 (in terms of macro support), so I recommend to update to it.
You could probably use Ant for building, but since you are saying that you already achieved this with terminal I think it would be easier to create script, and run it using custom builder (go to project properties, click Builders -> New... -> Program and then set it up to run your script.
Related
I am using IntelliJ and would like to create a new Scala Package. In all of the instructions that I find online I see that I am supposed to select "Package" from the "New" menu. However, my "New" menu does not include "Package" as an option.
How can I add "Package" to this list or otherwise add a package to my Scala application?
Also as a side note, I am developing Scala applications and as such I would like for primarily Scala related templates to appear in this list as opposed to the menagerie or irrelevant templates that currently presents itself. How can I edit the list of templates that appears in this menu?
I solved this problem by taking the following steps:
Making sure to install both the Scala and SBT plugins. (I was missing the SBT plugin)
Copying all the source files (*.scala) into a temporary location
Deleting the project.
Creating a new project with the same structure and copying the source files into their proper location.
Now "Package" appears in the menu (and full syntax hilighting now works, which was the reason why I wanted to fix this in the first place). Note that simply installing the SBT plugin (step 1) was not sufficient in fix this problem.
Maybe it was a bug.
I am trying to set a breakpoint in a Scala Macro implementation using the Eclipse IDE and failing
Firstly: Scala Macros Rock! Up to now I have preferred Clojure to Scala, but with macros I'm no longer sure
I'm trying to create a macro that will return the toString of a function and the function itself. When that works I'm going to make a new function with a sensible toString. Ah happy days.
But I need to be able to debug the macros. I use Eclipse (20110615-0604), with Scala (2.10.1). I downloaded the scala-compiler-2.10.1.jar and the code from http://www.warski.org/blog/2012/12/starting-with-scala-macros-a-short-tutorial/ now works. I've written a couple of simple macros as well. The macros are in an eclipse project "ScalaMacro" and the code that uses them is in a separate project "HelloScalaMacro"
I'd now like to debug them
Following the instructions at http://docs.scala-lang.org/overviews/macros/overview.html I have created a runtime configuration with scala.tools.nsc.Main as the entry point. I've added -cp HelloScala.scala, and when I run the configuration it actually seems to compile the code (if I put errors in, it reports the errors correctly).
Unfortunately the instructions imply that a breakpoint in the macro implementation should cause Eclipse to pause. It doesn't.
I've done the usual: google search for Eclipse/Scala macro/Debug/Breakpoint, read all the stackoverflow questions in the scala-macro tag, and played around a lot with every eclipse setting I can find.
So if any of you out there know how to set breakpoints, could you let me know how: is it an eclipse version / scala version / ... issue?
I haven't tried this myself, and in principle it is as likely (or more likely) to fail as what you've already tried, but if successful it could be more convenient to you.
To try this you should have Scala-IDE along with the source feature installed. Make sure you are working off of an Eclipse installation that is either "Eclipse Classic", "Eclipse for RCP Developers", or a similar concoction you came up with on your own.
You will also want to install the Equinox Weaving Launcher plugin, that will allow you to create an "Eclipse Application with Equinox Weaving" launchers.
Now:
Create a new workspace
Create a Scala project
Plant your macro code in that project
Add a break point in the macro source
Getting ready to debug:
Create a new "Eclipse Application with Equinox Weaving" debug launch configuration. Give a name more elegant than "New_configuration".
under "location", point it towards a new different workspace directory
under the "configuration" tab, provide something like "-Xmx1536m"
By default, all plugins available to your running Eclipse instance should be available to the instance you are about to launch. Eclipse may need some cajoling in order to include a non-plugin project in the classpath -- if this doesn't work, that's the first thing I'd try to look at.
You will now want to launch the debug configuration.
Depending on your Scala-IDE version, you may encounter a "Multiple launchers available -- Select one..." warning. I'd go for "Equinox Weaving enabled Eclipse Application Launcher".
Once inside the Eclipse instance being debugged:
Create the project you want to use the macro
Make sure to add a dependency on the binary output
Add a small usage example of your macro to the project in the workspace being debugged.
Cross your fingers
Build
In theory, the launching Eclipse instance will now pause the instance being debugged on your break point.
The instructions given by Nadavwr (just below) were helpful, and I recommend them to other people.
The key solution for me was to realise that there are two projects involved, the project that defines the macro, and the project that uses the macro. Rather foolishly I was trying to debug the project that defined the macro
So the instructions as given in the documentation are correct, I just had to make sure I was running them in the correct project: obvious of course.
For the benefit of other people, I found it very helpful to use a command line scalac to get the command line correct: much quicker editing that, and controlling which directory I was in, then in eclipse
The other thing to realise for people thinking of using Scala Macros are that the error messages from running scalac directly are MUCH better than those from eclipse.
This question is not limited to lex and yacc, but how can I add a custom script compiler as part of a project? For example, I have the following files in the project:
grammar.y
grammar.l
test.script
The binary 'script_compiler' will be generated using grammar.y and grammar.l compiled by lex, yacc and g++. And then I want to use that generated script_compiler to compile test.script to generate CompiledScript.java. This file should be compiled along with the rest of the java files in the project. This setting is possible with XCode or make, but is it also possible with Eclipse alone? If not, how about together with Maven plugin?
(I might setup the script compiler as a separate project, but it would be nice if they can be put in the same project so that changes to the grammar files can be applied immediately)
Thanks in advance for your help!
You can add a custom "Builder" from the project properties dialog. This can be an ant script (with an optional target) or any other script or executable.
There are also maven plugins for ant and other scripting languages
If you just want to run an external program in Maven this is what you want: http://mojo.codehaus.org/exec-maven-plugin/ -- you can then run Maven targets from your IDE or command line and it should do the right thing either way.
To integrate with the normal compilation bind the plugin to the "generate-sources" phase and add the location where the Java files are generated to the "sourceRoot" option of the exec plugin. That way the compiler will pick them up.
Ideally you generate the code into a folder "target/generated-sources/MY_SCRIPT_NAME". That is the standard location for generated sources in the Maven world and e.g. IntelliJ IDEA will pick up source files inside of that location. Note that this doesn't work if the files are directly in "target/generated-sources".
The other option is to write your own Maven plugin, which is actually quite easy as well. See e.g. https://github.com/peterbecker/maven-code-generator
I am new to intellij idea and I decided to shift because I found the scala plugin on eclipse to be annoyingly buggy.
But, intellij idea, which I have heard to be very good, looks difficult to use.
I looked through the getting started with scala plugin page but couldn't find documentation specific to the latest version of lightweight ide of intellij idea 11 for scala.
I have created a project and made a hello world object in scala but I am not able to run it.
On trying to run it, it shows the scala interpreter (type in expressions to get them evaluated).
I don't exactly understand what changes to make in the project structure to be able to run scala code. As of now, i added the jsdk to point to my $JAVA_HOME and the scala library is also added. The scala plugin is also working in that syntax highlighting etc is fine.
The intellij idea user interface is also not very friendly and I don't get how to run the code. What modules am I supposed to add? Also, does compiled scala code run with jvm?
I'll be grateful to anyone who helps out.. I have been putting off writing scala code because I am not able to find THE IDE.
EDIT: Thanks for all the help! I am now able to run a basic scala program. I am trying to add external jars. What is the equivalent of doing Project right click-> Configure Build Path -> adding external jar files in eclipse? I tried adding "dependencies " under modules tab in project structure. It's adding the jar files but somehow the classes in the jar files are not still recognised.
With the Scala plugin installed either
A. Create a new project and select the Scala facet in the creation phase. It will create the Scala library lib and Scala compiler lib and setup the facet for you
B. If you already have a project. Go to Project Structure -> Modules and right click the module and go Add facet and add a Scala facet. Now you need to add scala-library.jar as a library of the module and go into the Scala facet and point it to a library containing scala-compiler.jar
Some more information
this is what your module should look like under project settings
select the Scala facet and this is what you should see (Library name for the compiler is unimportant as long as it says (version xxx) next to the library name
these are the jar files in my scala-compiler lib
and these are the jar files in my scala-library lib
With everything setup like that you should be able to right click -> new Scala class (Select object from the dropdown) in a source directory and add
def main(args:Array[String]) {
println("Hello world")
}
then right click on the class and select Run Classnam.main() and IntelliJ will setup a run configuration for you.
Edit: I can see someone posted somewhat the same I want to say here. I hope this can give a few more in-depths hints, so I will post it anyway :-)
If you would like to run Scala native in IntelliJ (I shifted to IntelliJ and still can't get my hands down) you need to make sure a few things are in order. Most of this happens under File -> Project Structure which requires you to create a project (when you get a hang of it, it is much more logical than Eclipse -- and Netbeans for that matter). I am also assuming you have selected a jdk, but this can also be done in the Project Structure.
Now, to Scala:
Make sure you have the Scala plugin. Visit the Settings (File -> Settings; can also be found at the start-up screen) and locate 'Plugins' (for me it's nr. 8 from the bottom). Under "Browse Repositories" you should be able to search for "scala", find and install a plugin.
1 A. If no plugins pops up you are probably using a version of intellij where scala is not (yet) supported. If that happens you can go to the homepage for the plugin and download the nightly build.
Import Scala as a library in File -> Project Structure -> Global Libraries. Click the plus sign, select Java (Scala is a Java-lib), browse to your scala-dir (which can be downloaded here: http://plugins.intellij.net/plugin/?id=1347) and select the lib directory. Press ok and you should see the library popping up on the list.
Make sure the facet (Scala framework) is in place. Goto File -> Project Structure -> Facets. Click on the plus-sign and find Scala. A sublink should appear (if not double-click the Scala link). Clicking the sublink make sure you have selected a compiler before continuing. This should be provided by the modules selected before. I normally use FSC (Fast Scala Compiler) but it's probably a good idea to test the basic settings before experimenting.
Make sure the Scala Module is in place. In Project Structure -> Modules click on the module you want to compile in scala and click the plus icon above and select Scala. Again be sure to select a compiler library.
If you want to, setup configurations for the compiler under the facet
Use sbt with sbt-idea plugin to generate idea project files for complex projects.
Or
For simple projects.
Add scala nature to the project, and you can right click and run any file extending App.
A good walk-through on how to set up a Scala project in Intellij is located here:
http://sonyarouje.com/2011/03/18/running-scala-in-intellij-idea-10/
I need to run some example java code. I like using eclipse because it shows the methods, properties, constructors and so on. The problem I'd like to solve is that unless I create a new project I can't compile and run the example code I'm using! Is there a way around this?
No, there is no way around this. A Java file is very rarely a self-contained program with no dependencies at all. Most of the time, a program is composed of many collaborating classes depending on external libraries.
If you just want to test a self-contained Java program consisting of just one java file, then create a "playground" eclipse project, drop this file inside this project, and run it. Use the same playground project for all the other self-contained java programs if you want: you may have several main classes inside a single eclipse project.