setInterval()- set the delay between successive evaluations of a task for a waitThread object. The main purpose of this function is to allow an idle waitThread to be parameterized after creation such as after
new("waitThread"). We are allowing access to this, but don't envisage it being used much.
Tin which case the length is infinite. The request to set the interval value is added to the end of this list and can only take effect then.
If one wants to change the interval value during a sequence of repeated tasks, cancel() the thread and start a new one. The expression for the task can be retrieved using threadQueue
What should the return value for threadQueue in the case of a virtual infinite queue? Should pass back interval also and the current number of repetitions completed.
timerThread = waitThread(1, Quote(print(i=i+1)),data=list(i=1)) .. .. setInterval(timerThread, 2)