EventScript: An event-processing language based on regular expressions with actions

EventScript is a simple but powerful language for programming reactive processes. A stream of incoming events is matched against a regular expression. Actions embedded within the regular expression are executed in response to the matching of patterns of events. These actions include assigning computed values to variables and emitting output events. The definition of EventScript presented a number of novel and interesting language-design choices. EventScript has an efficient implementation, and has been used in a development environment for complex event-based applications. We have used EventScript to program both small examples and large industrial applications. Readers of EventScript programs find them easy to understand, and are comfortable with the familiar model of matching regular expressions. © 2008 ACM.