I am a little bit guessing (because I did not build a test project to verify this), but the "right hand sides" are constant values and not key paths. So you should replace
[NSExpression expressionForKeyPath:@"Awaiting inputs"]
by
[NSExpression expressionForConstantValue:@"Awaiting inputs"]
in NSArray *right=@[ ... ]
, and similarly for the other possible values.