Current Position Information
Previous exit stop price
At position entry time, PrevExitStop is set to 0.
On each bar that the position is open, after the ExitStop formula is calculated, its value is placed in PrevExitStop.
This makes it possible to implement a "trailing stop", or any type of price stop concept that needs to refer to its own prior value to be calculated.
(Previously this required using the Data Section and was therefore more complex.)
It is also possible for a strategy to refer to the current exit stop price of another strategy by using Extern(@other, PrevExitStop).
This is a very simple trend-following strategy with a 3*ATR trailing stop: