$string = 'abcd';
$regex = '^' . join '', map "[^$_]*$_", map quotemeta, split //, $string;
# embed capture to get offset:
$regex =~ s/(?<=\*)/(/; $regex =~ s/$/)/;
$sequence = 'xxxxxaxxxxxxbxxxxxcxxxxdxxxxx';
if($sequence =~ /$regex/s) {
    printf "I found a match, at offset %d and with total length %d\n", $-[1], $+[1]-$-[1];
}