For example, the attached file …

Is it because the attributes and VEX are still under development? Or am I doing something wrong?
Please, I would like to know what to learn and how to do it right.

If I “Allow Editing of Contents”, I can rebuild the Matchaxis and make it work. Is it because the “chv()” cant evaluate @my.x?

Are there some general rules, where to use @my or @my.x? What about the @Cd.r?

What if I want to use an array value inside the Transform SOP? Do I have to “extract the value” with Wrangle prior to using Transform SOP?