Your right Abigail.

In the scheme of how future perl releases will behave, it is undefined. and is therefore unpredictable. I wasn't disagreeing with this.

In terms of how any given installation of perl behaves now, then Deparse can illuminate the order in which things are evaluated. And if you inspect a few similar sets of Deparse outputs it becomes predictable how other similar expressions wil be evaluated for that given installation.

This doesn't remove the risks associated with relying upon the current behaviour, and was not meant to encourage such reliance. Only to explain that behavour and show that it isn't random. Just unwritten and subject to change.