The following code from the example in the Application section of http://reference.wolfram.com/language/ref/ScheduledTask.html.
CheckForFullMoon := If[MoonPhase[Tomorrow] > 0.99, SendLunarAlertMail]
This code uses a constant, 0.99, but if I want to replace the constant by a previous value (such as MoonPhase[Yesterday]). How to do that?
P.S. In fact,I want to compare the price between today and yesterday, so Wolfram Cloud should remember the price of yesterday. I have no idea how to remember the values of a previous case in the cloud.