A language, server and C++ class library for event sequencing
Vern Paxson, C. Saltmarsh, M. Allen, M. Kane · Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · 1990
Many accelerator control tasks are well specified as a sequence of operations, each step of which is contingent upon the status of other operations or sequences. To enable the rapid creation and modification of such sequences we have devised the “Glish” language. Sequences are described in Glish in terms of asynchronous hardware and software “events”, where an event is the notification that a particular thing has happened and the value associated with that notification. Events are produced and consumed by UNIX processes. One uses Glish to write expressions which specify how events associated with the processes depend on combinations of other events. We describe the Glish server, which manages Glish events distributed across a network, a C++ class library for Glish clients, and operational experience gained in using Glish to control an accelerator physics experiment on the Fermilab Tevatron.