| add | A function with the argument list function(f, data = NULL, name = NULL, register = TRUE), which
adds the callback function f and possibly the object data and the name name
to this callback manager's list of callback function. If register is
TRUE, and if this callback manager has not already been registered with the
top-level callback system (see addCallback), then the callback manager
is registered so that all the functions in its callback list are run at the end of each
top-level expression. f must return TRUE or FALSE. (FALSE means
to remove it from the callback manager's list of callback functions.) |
| evaluate | A function with the argument list function(expr, value, ok, visible)
that calls each function on this callback manager's callback list with those
arguments, and possibly the data argument stored along with the callback. |
| remove | A function with the argument list function(which), where which
should be either an integer position in the callback list or the name of an item
in the callback list. This function returns TRUE if which actually refers
to an item on the callback list (which means that item was removed) and FALSE
otherwise. |
| register | A function with the argument list function(name = "R-taskCallbackManager", verbose = .verbose)
that calls addTaskCallback(evaluate, name=name) so that all of the handler's
callbacks are called after each top-level expression. Also, this function sets the
internal registered flag so that subsequent calls to add do not
cause the list to be evaluated again. |
| suspend | A function with the argument list function(status = TRUE). This function sets an internal
flag, which, if TRUE, causes evaluate to not evaluate the functions on the
callback list, but without taking any callbacks off the list. suspend(FALSE) causes
evaluate to resume normal behavior. |
| callbacks | A function with the argument list function() that returns the list of
callback entries. Each entry is a list with a component f, the callback function itself,
and possibly (data), the optional object to pass to f each time it is called. |