|Think about Loose Coupling|
Re^4: Why doesn't Perl provide %_ as the hash equivalent of @_ in subs?by vsespb (Chaplain)
|on Sep 26, 2013 at 11:45 UTC||Need Help??|
that doesn't mean the magic variable should not be provided at all, it just means it should be read-only.That looks like inconsistency to me.
Above two examples are not identical. Later one is something low-level, and it's just asking for trouble (for example in cases like f2($1), f2($.) or f2($x, $x) when z() modifies arguments ).
(NOTE: another common point of view is that caller of such functions is asking for trouble)
So IMHO you should not use @_ just because it's shortest. Use it when you know what you're doing.
And now you suggest add another %_ which behaves completely different way.
Also making %_ readonly won't help much in cases when you pass magic variable as argument (example: RT#54728).