my $regex = "(^[1-3]|^yyy|^zzz)";
my @regexs = convert($regex);

would create a list like
$regexs[0] = "^1"
$regexs[1] = "^2"
$regexs[2] = "^3"
$regexs[0] = "^yyy"
$regexs[0] = "^zzz"