SmallWorld

SmallWorld is a very simple Smalltalk Virtual Machine written in Java. It is derived from Tim Budd's Smalltalk. The original import in this repository was taken from the state of the SmallWorld.tar file found at http://web.engr.oregonstate.edu/~budd/SmallWorld/Source/SmallWorld.tar dated 10-Nov-2004.

This version extends the original in several ways:

• The serialization format no longer depends on Java serialization.
• The GUI has been decoupled from the interpreter.
• The Smalltalk classes are in plain text files for easier browsing. These were extracted from the main image using Class>>fileOut. Also included are some classes (related to the compiler) which are in the image, but not listed in the main class browser (they were probably explicitly hidden.)
• Code has been reformatted, and warnings/deprecation reduced.

Running SmallWorld

SmallWorld is built and run with Gradle. Simply run

./gradlew run

and you're good to go! It will open a Swing-based user interface for evaluating expressions, browsing classes, and so on.

SmallWorld from the command line

It is possible to run a version of SmallWorld from the command line. Look at build.gradle for more details. If you change to the repl main class, then ./gradlew --console=plain run will start the interpreter. The text that you enter will be compiled and the result printed with printIt. For example:

> Task :commandline
image initialized
SmallWorld> 3 + 4
Running task: 3 + 4
SmallInt: 7
Task complete
SmallWorld> 'hello' size
Running task: 'hello' size
SmallInt: 5
Task complete
SmallWorld> ((1 / 3) + (3 / 4)) printString
Running task: ((1 / 3) + (3 / 4)) printString
(13/12)
Task complete
SmallWorld>

Hit Ctrl-D to exit.

Experimental features

The experimental directory used to contain a highly experimental version of SmallWorld that used TeaVM to translate the Java bytecode into JavaScript. This code somewhat worked, but was very incomplete. In the meantime, I have created an alternative implementation of SmallWorld. In smallworld.js I rewrote SmallWorld directly in JavaScript, including a port of the GUI to HTML. There is also a native HTML UI that allows Smalltalk code to update the DOM of the Web page on which it is running. I recommend checking out smallworld.js.