The Emacs command loop reads a sequence of input events that represent keyboard or mouse activity, or system events sent to Emacs. The events for keyboard activity are characters or symbols; other events are always lists. This section describes the representation and meaning of input events in detail.
This function returns non-
nil if object is an input event
or event type.
Note that any non-
nil symbol might be used as an event or an
eventp cannot distinguish whether a symbol is
intended by Lisp code to be used as an event.