FunBar makes it possible, in some cases, to calculate with a one-line function call a complex formula that otherwise need to be written with looping code.
As a simple example of how this works, the following shows the evaluation steps of Sum(FunBar, 5):
Within the internal calculation loop of the Sum function, FunBar starts at 1 for the earliest bar, then is incremented as the calculation proceeds.
For a more complex example, see the ehlers_windows.rtsexample script.