Event-Driven Programming

• Event-Driven Programming
• Early Smalltalk Philosophy: "Don't Mode Me In"
• Creating non-modal interfaces:
• User events collect in queues
• Program polls queues and processes them according to context
• Macintosh, Windows, Java AWT, and X-Windows GUI programming all event-based
• Programming with Events: Merging the Controller into the View
• Each interface component sends pre-defined messages (events)
• The model can choose to use (implement handler) or ignore each event
• HyperCard as Example
• Buttons, Fields, Cards, Background, and Stacks
• Object-BASED but not Object-ORIENTED