#! perl

my $str = '.,a..A,,C..+4ACGTG.,-2TG,,...,a.';

print replace($str);

sub replace {
	my $str = shift;
	if ($str =~ m/([+-])(\d*)/) {
		$str =~ s/\Q$1\E$2.{$2}//;
		return replace($str);
	}
	return $str;
}