Ambient-Oriented Programming

AmbientTalk is a distributed programming language developed specifically for writing programs to be deployed on mobile ad hoc networks. A distributed programming language is often characterised as a programming language with built-in support for aiding the programmer in dealing with the difficulties engendered by distribution. If you wonder what those difficulties would be, a good starting point are the well-known fallacies of distributed computing.

For the programming language adepts: AmbientTalk is:

1. dynamically typed, which is not the same as being untyped: AmbientTalk values are typed, but variables are not)
2. object-oriented, but prototype-based: AmbientTalk provides full support for objects, delegation (a form of inheritance) and polymorphic message dispatch. Objects are not instantiated from classes, as in Smalltalk, but rather cloned from existing objects or created ex-nihilo, as in Self.
3. event-driven: AmbientTalk has built-in support for actor-based concurrency, which operates based on entirely asynchronous and event-driven communication. No threads, no locks, no deadlock and no data-level race conditions!
4. distributed: AmbientTalk has built-in natives to make objects discover and talk to one another in a peer-to-peer manner across a TCP/IP network.
5. symbiotic: built on top of the Java Virtual Machine, AmbientTalk exploits the Java reflection API to enable AmbientTalk objects to collaborate with Java objects. This enables reuse of existing Java libraries while not abandoning the dynamic programming style of AmbientTalk.

A word of warning, though: AmbientTalk is not a stable development platform. Rather, it is a research artifact used as a “programming language laboratory” to experiment with and discover new language abstractions for distributed computing in mobile ad hoc networks.

Enough talking, let's delve into some AmbientTalk code by means of a simple example to see whether we can spark your interest in AmbientTalk. The demo program we're about to explore is an extremely simple instant messenger program. Each instant messenger runs on e.g. a PDA, laptop or cell phone. When peers join the ad hoc network, the instant messenger should issue a warning to the user that a new buddy is available for chatting. The user can then send simple text messages to that buddy. Off we go: