Thing you can receive notifications from, as well as task-switch on
Note that every event source can control task switching, but not every
task switcher is an event source. Generators, for example, can control
task flow, but do not really produce any "events".
Event callbacks must not raise errors, as event sources are not required
to ensure that all callbacks are executed when a callback raises an error.
|
Methods
|
|
addCallback
|
|
|
addCallback
|
addCallback ( func )
Call func(source,event) the next time this event occurs
Usage::
canceller = source.addCallback(somefunc)
If this method is called from within a callback, func must not be
invoked until the next occurrence of the event.
Note also that callbacks will be called at most once for each time
they are registered; adding a callback does not result in an ongoing
"subscription" to the event source.
This method should return a canceller object that can be called to
cancel the callback. Cancelling a callback that has already occurred
or been cancelled is a no-op. (Note that even if the same func is
passed to addCallback() more than once, each individual canceller
must cancel that specific occurrence, and no other.)
|
|