Making Events Less Slippery with eel

Event-driven programming divides a program’s logical control flow into a series of callback functions, making its behavior difficult to follow. However, current program analysis techniques can preserve the event model while making event-driven code easier to read, write, debug and maintain. We designed the Explicit Event Library (libeel) to be amenable to program analysis, and created tools to graphically expose control flow, verify resource safety properties, and simplify debugging. The result sustains the advantages of event-driven programming while adding the important advantage of programmability.