Lambda the Ultimate

Computation Orchestration: A Basis for Wide-Area Computing, Jayadev Misra and William Cook. JSSM 2006.

The widespread deployment of networked applications and adoption of the internet has fostered an environment in which many distributed services are available. There is great demand to automate business processe and workflows among organizations and individuals. Solutions to such problems require orchestration of concurrent and distributed services in the face of arbitrary delays and failures of components and communication.

We propose a novel approach, called Orc for orchestration, that supports a structured model of concurrent and distributed programming. This model assumes that basic services, like sequential computation and data manipulation, are implemented by primitive sites. Orc provides constructs to orchestrate the concurrent invocation of sites to achieve a goal -- while managing time-outs, priorities, and failure of sites or communication.

The idea of orchestration languages is one of the good ideas to come out of the web services world. Orc is an elegant little process-calculus-inspired programming language that illustrates and embodies the key ideas, and I'd recommend studying it to anyone who has even a passing inclination to design languages or libraries for "mashup" style programming.