Thanks! That was a cool solution. One caveat though, the variables to be checked must be visible (scope-wise) to the eval:

use strict;
use warnings;
 
my $foo = "1";
my $bar = "42";
 
my $defnz = sub {
  for (@_) {
    if (!defined(eval($_))) {
      print "$_ undef!";
      return;
    } elsif (eval($_) eq '') {
      print STDERR "$_ empty!";
      return;
    }
  }
  return 1;
};
 
my $baz = "101";
 
print "ok1\n" if &$defnz(split /,/,q($foo,$bar));
print "ok2\n" if &$defnz(split /,/,q($foo,$bar,$baz));
 
__END__
ok1
$baz undef!
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