An answer from the K.I.S.S. school of thought...
I created a calculation field that either returns a text value or "?".
P.S. By "?" I don't mean the text question mark, I am refering to the filemaker error message.
Have your calculation return a 'real' text value or a text value that couldn't possibly be a valid result (e.g. "mccartyisthecoolestdudealiveandimnotkidding" )
In a script, I have an If/Else statment that needs to figure out if what is in this field is text or "?".
Now simply figure out if what is in the text is "mccartyisthecoolestdudealiveandimnotkidding" or if it is something else.
Would that solve your dilemma?
Actually no that wouldn't solve the problem. No worries though, I decided to find the information I need in a subscript instead of trying to have the calculation do it for me. Thanks anyways