my $str = "ABC\"123\"XYZ";
my @p = split /(?<!\")(?=\".*\")|(?<=\".*\")(?!\")/, $str;
foreach my $part (@p) {
   print "part = ($part)\n";
}

__error__
Variable length lookbehind not implemented before HERE mark in regex m/(?<!")(?=".*")|(?<=".*")(?!") << HERE /