SOMns - A Simple Newspeak Implementation

Introduction

Newspeak is a dynamic, class-based, purely object-oriented language in the tradition of Smalltalk and Self. SOMns is an implementation of the Newspeak Specification Version 0.0.95 derived from the SOM(Simple Object Machine) class libraries, and based on the TruffleSOM. Thus, SOMns is implemented using the Truffle framework and runs on the JVM platform.

A simple Hello World program looks like:

class Hello usingPlatform: platform = (
  public main: platform args: args = (
    'Hello World!' println.
    ^ 0
  )
)

Implementation and Deviations from the Specification

SOMns is implemented as self-optimizing AST interpreter using the Truffle framework. Thus, it can utilize the Truffle support for just-in-time compilation to optimize the execution performance at runtime. It is completely file-based and does not have support for images. The parser is written in Java and creates a custom AST that is geared towards representing the executable semantics.

The overall goal is to be compliant with the specification, but include only absolutely necessary features. The current list of intended deviations from the specifications are as follows:

• the mixin support of slots is not yet complete, see deactivate tests in core-lib/TestSuite/MixinTests.som

• simultaneous slots clauses are not supported (spec. 6.3.2)

• the file syntax is adapted to be more practical. This includes that category names are optional instead of being mandatory.

• setter send syntax is still based on the classic Smalltalk :=

• local variables in methods do not yet support the full slotDeclartion style

• as in SOM method chains are not supported

• as in SOM, blocks can only have 3 arguments (counting self)

Obtaining and Running SOMns

To checkout the code:

git clone https://github.com/smarr/SOMns.git

Then, TruffleSOM can be build with Ant:

ant jar

Afterwards, the simple Hello World program is executed with:

./som core-lib/Hello.som

Information on previous authors are included in the AUTHORS file. This code is distributed under the MIT License. Please see the LICENSE file for details.

Setup Development Environment

1. Install JDK 1.8 and Eclipse Mars (or later)

2. Download the project from Github https://github.com/smarr/SOMns

3. Configure in Eclipse SOMns project In option Run Configurations go to Java Application/SOMns and select tab Arguments, then copy:

In Program arguments: core-lib/Benchmarks/Harness.som Mandelbrot 1 0 500

In VM arguments: -ea -esa

4. Run ant on the command line, or via Eclipse, to make sure that all libraries are loaded and available.

5. Start Truffle service $ cd libs/truffle/ $ ../mx/mx eclipseinit

6. Test SOMns with Mandelbrot file $ ./som -G core-lib/Benchmarks/Harness.som Mandelbrot 2 0 500

Build Status

The current build status is:

Academic Work

SOMns is designed as platform for research on concurrent programming models, and their interactions. Here, we collect related papers:

• Optimizing Communicating Event-Loop Languages with Truffle, Stefan Marr, Hanspeter Mössenböck; Presentation at the AGERE!’15 Workshop, co-located with SPLASH’15.