Tutorial 179 | Using AppStorage in the calculation of price change since program first applied

TradeStation EasyLanguage Tutorial 179 uses AppStorage to store the price of a symbol when the tutorial program is first applied (and the date when the program was applied.) According to the TradeStation help files, AppStorage is "A Dictionary of name-value pairs that will be persistent when an analysis technique is re-verified, has its inputs modified, or re-runs for another reason (such as when it is disabled by the user temporarily, and then enabled again)."

This initial value is then used to calculate the change from the most recent close. The value of the date and 'last' price when first applied are retained even when RadarScreen is refreshed (by pressing CTR-R) or when the workspace is saved, closed and later re-opened.

If the user wanted to re-store all the initial values then the program should be deleted from Radarscreen and re-applied.

For more information about AppStorage see: https://markplex.com/free-tutorials/tutorial-119-storing-chart-data-appstorage/

For an explanation of 'Load Additional Data for Accumulative Calculations' and MaxBarsBack in RadarScreen see:
https://markplex.com/free-tutorials/tutorial-25-understanding-smoothed-indicators-load-additional-bars/

The tutorial uses a TokenList to process a comma delimited string. TokenLists make it very easy to refer to individual elements of the comma delimited string.

The tutorial actually demonstrates two programs. In the first the Last keyword is used to refer to the stock price when the program is first applied to RadarScreen. In the second version, Close is used.

See: https://markplex.com/free-tutorials/tutorial-179-using-appstorage-in-the-calculation-of-price-change-since-program-first-applied/