re.group.{N}
STRING, read-only.
Available inall subroutines.
If N is numeric, it extracts the N-th capture group from the most recently
executed match operator.
N can range from 0 to 19; re.group.0 evaluates to the entire matched string
even if no capture groups have been supplied.
If N is an alphanumeric identifier that does not start with a digit, it is
interpreted as a named capture from the match. If no such named capture exists,
NULL is returned.
