With the advent of Perspective, array and object property types are used extensively, however there’s no way to really use these in the expression language e.g. to lookup a value within an array or an object and return the found value.
Can new expression functions be added, or can existing ones be modified to allow this? (e.g. lookup)
Vote here:
indexOf and ‘slicing’ syntax should work. It’s not as elegant as lookup, but there was some reason I didn’t add support for lookup when I implemented this for other expression functions I no longer remember.
Hmm, I tried some things and I'm not sure how to use slicing here? 
the expression language doesn't seem to see the array as an array, even something like a[0] or a[0,0] doesn't work where a is an array
That’s exactly what I tried I think it was in 8.1.5 though. Was that added more recently? Regardless though, I don’t think that helps to find an item in the array, or does it?
8.1.8 or higher:
https://docs.inductiveautomation.com/display/DOC81/New+in+this+Version#NewinthisVersion-Expressions.1
Gotta get that upgrade done 
Sigh it’s happening in 2 3? weeks. I won’t know what to do without myself once it’s done 
