I am making a program which needs a function to run, and it defaults to Y1. I want to check to see if Y1 has an equation stored, and if it doesn't, prompt the user for a Yvar that they want to use instead. I tried using
:If Y1=0 :Input "F(X)?",Y1
but instead of returning true, the program crashes if there is no equation in Y1. If there is an equation, it skips this statement (like it should)
Is it possible to determine if there is a value stored in Y1? If so, how? If not, is there anything I can do to get around this issue?