__PACKAGE__ is only special when used as a constant; putting it in a string (or a regex) makes it not a constant. While you could do ... =~ quotemeta(__PACKAGE__), this is not the issue. If you want to see if the first argument to your function is an object, I would suggest: 
sub something {
  if (eval { $_[0]->isa(__PACKAGE__) }) {
    # object call
  }
  else {
    # function call
  }
}

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Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart

In reply to Re: regexp and __PACKAGE__ by japhy
in thread regexp and __PACKAGE__ by jeanluca

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