Sorry. I cut&paste from one of my existing scripts (which didn't support them), and didn't spend the time to merge it with yours. Yes, I probably should think about modifying my code to take some of the improvements you suggest

Your "wrap" works because you are willing to require the user to pass the handle-container in as a typeglob (returning localised filehandles starts to hit the bugs). I didn't want to do that because the natural interface is a signature of (&) so that its single arg is a codeblock. To mimic the "open" builtin it'd need a signature of (*&) which would clutter user-code with the "sub" keyword.