Introducing EScript - scripting for your IDE

During the last years I was playing around with a scripting engine supporting JavaScript that is directly integrated in Eclipse. This engine is used as a basis for my RCPs to allow users to create their own workflow.

I thought this might come in handy for others too, so I raised bug 365133. In the meantime I was able to extend the framework and added other interpreters as well. Currently Rhino, JRuby and Jython are supported (some better, some worse).

Hoping to get feedback from the community (you!) I release this project into the wild. Check out the project homepage, or dive directly into the source at github.

"What can I do with such an engine?", you may ask.
At my company we use it to automate test equipment, create test patterns and accumulate test results. Therefore we need to commuinicate with lots of lab equipment like oscilloscopes, RFID readers and so on. As our work flows are very dynamic, we provide a script environment along with command sets to easily access these devices. Our users may then create their dedicated tests by implementing their own scripts.

By creating libraries (which are independent of the used interpreter!)  you may extend the script languages with your own functionality. Find an example at the EScript homepage.

You may also access any class available in your IDE and directly call methods on it.

All source is available under EPL terms. Drop me a line if you find it useful or need some support.
Please be aware that despite the Rhino implementation is available for quite some time, other interpreters were added just recently. So be prepared for some surprises :)

Eclipse integrated JavaScript Interpreter

I am working on an integration of Rhino (a Java based JavaScript interpreter) into the Eclipse IDE. Target is to execute JavaScript code directly within the running Eclipse environment. Such an interpreter might be used to script Eclipse itself. Wouldn't it be nice to have macro support?

Therefore I raised bug 365133. As I finally was able to post some code I'd like to give a short overview of what can be done.

Run Plug-ins

You need at least Eclipse 3.7 with JSDT tools installed (get them from the Indigo repository).

Import all four projects from the archive to your workspace. Right click one one of them in Package Explorer and select Run As -> Eclipse Application.

JavaScript Shell

Before we have a look at the integrated JS shell we will quickly adjust some settings: open menu Window -> Preferences and navigate to JavaScript -> Shell. Set all output values to "Shell".

Now open the shell view: select menu Window -> Show View -> Other... Then open view JavaScript -> JavaScript Shell.

The shell consists of a big output pane and an input line at the bottom. Start entering your first JS code there:

i = 2+2;

You will see the result right in the output pane. There is a print command available that will dump text to the Console view.

print("Hello world!");

An integrated help is available when hitting the help toolbar button.

JavaScript Run target

To execute JavaScript files there exists a new run target that allows to right click any JS source file and select Run As -> JavaScript. This will create a new interpreter (so it will not run in the same context as the shell) and execute the file.

Loadable Modules

For developers there exists an interesting Plug-in: com.example.javascript.modules.tools. It is an example how to extend JS functionality. Every method within this class augmented with @WrapToJavaScript
will be available as JS function automagically. This way JS functionality can be easily extended while using the benefits of Java.


Due to Rhino and the used ClassLoader it is possible to mix JavaScript code and pure Java classes. Eg the following JS code will create an instance of java.io.File and call a method upon it:

var myFile = new Packages.java.io.File("~/.bashrc");
print(myFile.exists());

Wrap up

Having a native JS interpreter within Eclipse will provide great new ways to build applications. It might give us macro support, rapid testing facilities for programmers (just load your Plug-in and access it with the Script Shell) and maybe a lot more things I can currently not think of.

If you want to support this idea please vote on bug 365133 or help in finding ways to make this part of Eclipse.