Purpose: [What is the purpose of this page?]
It's useful to distinguish two kinds of event processing in Tcl, that having to do with stream-oriented input-output [some reference here], and the events of Tk's WIMP user interaction, detailed in "windowing system events". Note, thought, that both exploit the notifier.
It's also important to understand the Tcl event loop, and the general concepts of Event programming and why it is relevant to Tcl/Tk programming.
Is there also an idea of some sort of user defined events - something not associated with either window systems or I/O ?