langreiter.com plain, simple: rebol-notes-events

LANGREITER.COM plain, simple

START

INDEX

rebol-notes-events

CREATED BY chris • LAST EDITED BY chris 8315 days AGO

The event! datatype is for GUI (input) events only, not for other types of system events. The universal i/o and signalling mechanism in REBOL consists of ports and 'wait. Timers would be implemented using ports as well. An "event" in its abstract notion is simply "something that happens asynchronously". In REBOL this concept is captured by data arriving at a port and that port signalling the arrival to a pending 'wait call.

"Event-driven programming" has nothing to do with the event! datatype. It simply describes a style in which the program waits in a single, central place most of the time, and the program flow is driven by external influences. In REBOL you do this by using ports and 'wait. If you want to handle GUI events as well then ONE of the ports you wait for is the global event-port, but other than that there is no impact on your event loop, and it is certainly not necessary to use the event-port to write event-driven programs.

Holger Kruse on REBOL-L, 2002-01-30.