ScalaInterpreterPane

statement

ScalaInterpreterPane is a Swing component for editing code in the Scala programming language and executing it in an interpreter. The editor component is based on SyntaxPane. ScalaInterpreterPane is (C)opyright 2010–2021 by Hanns Holger Rutz. All rights reserved. It is released under the GNU Lesser General Public License v2.1+ and comes with absolutely no warranties. To contact the author, send an e-mail to contact at sciss.de.

requirements

This project builds with sbt against Scala 2.13, 2.12, 3.x. The last version to support Scala 2.11 was 1.10.1.

To use it in your own project, add the following to build.sbt:

libraryDependencies += "de.sciss" %% "scalainterpreterpane" % v

The current version v is "1.12.0"

There is also the assembly target which creates a standalone jar in targets.

contributing

Please see the file CONTRIBUTING.md

overview

There are two independent components, CodePane and Interpreter. The former encapsulates the Swing widget for editing source code with syntax highlighting. The latter encapsulates the Scala REPL.

All have their dedicated configurations, based on a division between (mutable) ConfigBuilder and (immutable) Config. A builder is implicitly converted to a Config when necessary.

For example, to create a plain code view:

    import de.sciss.scalainterpreter._

    val codeCfg     = CodePane.Config()         // creates a new configuration _builder_
    codeCfg.style   = Style.Light               // use a light color scheme
    codeCfg.text    = """List(1, 2, 3)"""       // initial text to show in the widget
    codeCfg.font    = List("Helvetica" -> 16)   // list of preferred fonts
    // add a custom key action
    codeCfg.keyMap += javax.swing.KeyStroke.getKeyStroke("control U") -> { () =>
      println("Action!")
    }

    val codePane    = CodePane(codeCfg)         // create the pane
    val f           = new javax.swing.JFrame("REPL Test")
    // the actual javax.swing.JComponent is found at codePane.component.
    f.getContentPane.add(codePane.component, "Center")
    f.pack()
    f.setVisible(true)

To create an interpreter:

    import de.sciss.scalainterpreter._
    val intpCfg = Interpreter.Config()
    intpCfg.imports :+= "javax.swing._"         // add default imports
    intpCfg.bindings :+= "pi" -> math.Pi        // add predefined bindings

    val intp = Interpreter(intpCfg)             // create the interpreter
    // invoke the interpreter
    val res = intp.interpret("""Seq.tabulate(10)(i => math.sin(pi * i/10))""")

The result of interpret is either of Interpreter.Result, e.g. Interpreter.Success carrying the name and value of the result.

CodePane and Interpreter can be manually patched together using an entry in the code pane's keyMap setting which queries the currently selected text using codePane.getSelectedText and feeding that into the interpret method. But it is more convenient to use InterpreterPane instead, which already combines the two. Furthermore, there is a utility widget LogPane which can be used to direct the console output to. Using SplitPane, a fully self-contained system can be set up, containing a code pane in the top, a status bar in the middle, and a console log in the bottom:

    import de.sciss.scalainterpreter._
    val split = SplitPane()
    val f     = new javax.swing.JFrame("REPL Test")
    f.getContentPane.add(split.component, "Center")
    f.pack()
    f.setVisible(true)

If you use scala-swing, the components can be wrapped using swing.Component.wrap(_).

limitations

• auto-completion is based on the standard Scala REPL's auto completion, thus will only see values which have been executed in the interpreter before
• Dotty support is very basic; auto-completion for argument lists is not yet implemented
• the result value of an evaluation is currently not directly available

related

For a standalone desktop application, ScalaCollider-Swing is very useful. It has a multi-document-adapter and window docking and comes with cross-platform and Debian-based binary installers.

There are various projects which provide similar functionality or part of the functionality:

• https://github.com/Bridgewater/scala-notebook - console in a browser interface
• https://github.com/jedesah/scala-codesheet-api - code sheet is a slightly different concept with respect to execution
• https://github.com/MasseGuillaume/ScalaKata2 - console in a browser interface
• https://github.com/bobbylight/RSyntaxTextArea - an alternative to JSyntaxPane
• http://code.google.com/p/scalide/ - Swing based REPL, stopped in 2009
• https://github.com/kjellwinblad/ScalaEdit - Swing based editor based on RSyntaxTextArea, stopped in 2011
• https://github.com/Centaur/scalaconsole - Swing based console, stopped in 2011