Scala Worksheet: instant evaluation

More than year ago we implemented first version of Scala Worksheet. It had convenient interface, but it was possible to make coffee, while worksheet would finish evaluation, so it was almost unusable.

Now, in Scala plugin of versions 0.30.383 and 0.32.550, Scala Worksheet supports almost instant evaluation (don’t forget to use Ctrl + Alt + W shortcut):

Additionally your evaluation results will be saved even on the IDE restart until you will clean it or re-evaluate.

We are also planning to add highlighting for the output, so any suggestion are welcome as it’s not obvious how to do it.


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29 Responses to Scala Worksheet: instant evaluation

  1. Pingback: Scala Worksheet: 即時評価で高速プロトタイピング | JetBrains ブログ

  2. Marius-Andrei Danila says:


    Great to see that worksheets are properly supported in Intellij. However, I cannot manage to make it work.

    I have created a SBT project, then a new worksheet. After inserting some code and pressing “Evaluate worksheet” nothing happens. Syntax & error highlighting work fine, but no results appear in the right panel.

    I am doing something wrong?

  3. Heiko says:

    It has become so fast, you even can’t see the results 😉

    I’m on OS X, Idea 13.0.2, Java 7. The previous plugin worked (slowly), now evaluation doesn’t take place or at least doesn’t show up.

  4. Anil says:

    I have Idea 13.0.2, Java 7. After pressing compile.. compile result doesn’t show up. Please fix.

  5. Richard says:

    Same here. I am on Windows 7, Idea 13.0.2, Java 7 and 30.383 does not work. I went back to 29.464 and it is working again.

  6. Igor Kolomiets says:

    Ура! Наконец. Спасибо.

  7. Alex says:

    Scala worksheet works really faster with scala plugin v0.30.383 (project jdk 1.6.0_45, bundled idea jre 1.7) but IDEA scala compiler fails with the same error as already submitted here:

  8. Max says:

    Can you explain me why the scala worksheet has a different behavior to the scala ide?

  9. Paul says:

    I have the same issue.

    How can I install newer version of plugin via intelliJ plugin downloads ? Scala plugin version available is 0.26.361 right now. And if I try to load the plugin from the disk, I get an error (incompitable to current version error)

  10. Angel says:

    I have just used it and if I have a worksheet that contains a lot of code that does not generate any output, the editor won’t allow me to scroll down and see my code.

  11. BIBHASH ROY says:

    Few days ago, my scala worksheet used to be interactive – meaning, on writing a line of code, it will automatically compile and the results used to be printed on the right pane. Now this is no more happening and I have to click the green button for evaluating the worksheet – why this is happening?

    • Dmitry Naydanov says:


      Do you use the same worksheet as few days before, with ‘Interactive mode’ setting checked? Also, do you use compiler server? Do you have other problems with compilation?

      Best regards,
      Dmitry Naydanov

      • Bibhash Roy says:

        How to set Scala worksheet to interactive mode – do I need to configure settings? If yes, please let me know how to do it. I do not understand it how the behavior got changed – now I have to press the green (“evaluate worksheet”) button always to execute code and get results.

  12. Misha says:

    Hello there,

    I am able to see instant evaluation when I include my code in a singleton object.
    However, when I include the object inside a package like so:

    package ABC {

    object BLAH {


    then I no longer see anything evaluated on the right hand side of my Scala Worksheet.
    I am new to Scala, so I’m not sure what I am doing wrong…

    Thanks in advance!

    • Craig says:

      I’m having the same problem. I’ve previously been using Eclipse, but wanted to try IntelliJ for a course I’m doing (it’s used in part of the course). But since it doesn’t currently work, back to Eclipse.

  13. Alex Tah says:

    is it possible to get the evaluated output to be placed right in the code window, and next to the relevant line of code (as in Eclipse), rather than a separate tab to the right?

  14. Alexander Podkhalyuzin says:

    The main idea behind separate tab is not to change user file at all. If you have any problems with tab synchronization or something else, please report it in our issue tracker. IntelliJ IDEA also recently supported inline hints (with no file change), so probably we will reuse this functionality for worksheets when it will support multiline hints.

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