AmbientTalk is an experimental object-oriented distributed programming language developed at the Software Languages Lab at the Vrije Universiteit Brussel, Belgium. The language is primarily targeted at writing programs deployed in mobile ad hoc networks.
AmbientTalk is a research platform to experiment with new language features or programming abstractions to facilitate the construction of software that has to run in highly volatile networks exhibiting intermittent connectivity and little infrastructure.
The language's concurrency features are founded on the actor model and have been largely influenced by the E programming language. The language's object-oriented features find their influence in languages like Smalltalk (i.e. block closures, keyworded messages) and Self (prototype-based programming, delegation). Finally, the language has a functional core, inspired by Scheme and Pico.
AmbientTalk's main differences with mainstream languages are that:
It employs a purely event-driven concurrency framework, founded on actors.
It abandons the RPC abstraction in favor of asynchronous, non-blocking message passing. Because the system automatically buffers such messages while the receiver of the message is disconnected, the programmer can abstract from temporary network failures by default.
It uses futures (aka promises) to ease the construction of event-driven, asynchronous workflows.
It has built-in programming language constructs for objects to discover one another in the local ad hoc network. Peer-to-peer service discovery is built into the language.
It features a dynamic OO kernel language built upon the principles of prototype-based programming. The kernel language supports reflection using mirrors, which provide access to an extensive metaobject protocol, making the language extensible from within itself.
The language syntax derives primarily from the 'curly brace' family of languages, but it mixes in the keyworded messaging syntax from Smalltalk as well. This, together with AmbientTalk's lightweight block syntax, enables you to easily build your own control structures.
The current implementation of AmbientTalk embraces the JVM as a platform. It's easy for AmbientTalk programs to use Java libraries, and it's easy for Java objects to use AmbientTalk as an embedded scripting language. This interaction is safe: even when AmbientTalk objects are "exposed" to the JVM, JVM threads cannot violate the concurrency constraints of AmbientTalk's actor model.
In this screencast on the AmbientTalk programming language, we show how to implement a simple echo service for mobile ad hoc networks. We introduce AmbientTalk's support for peer-to-peer service discovery, asynchronous messages, futures and how remote object references are resilient to network failures by default.