The Operational Feature Exchange Language

Abstract : This collection of documents describes the existing Feature Exchange Language (FEL) as it is implemented in the prototype Intelligent Machining Workstation (IMW). The original design of FEL is described, the FEL interface to several IMW subsystems (Planning, Modeling, and Holding) is explained in considerable detail, and the implementations for both the Sun Unix C++ and the TI Explorer Lisp environments are explained. FEL has been designed as a language for communicating messages in a distributed environment. FEL was designed to make parsing and generation simple. The assumption was that possibly many different computing platforms would require an FEL interpreter. It was assumed that FEL could tie together processes running on one machine or many, and therefore FEL was designed to represent the sender, receiver(s) and other information that could be useful in message transport. Features were chosen as the objects that should be communicated. Each feature has a name and a set of built in parameters that go with it. Each sentence of FEL has a verb that specifies how a message should be interpreted by a particular receiver. FEL was designed to represent complex message exchanges between distributed parties.