#!/usr/bin/perl

# http://perlmonks.org/?node_id=1196747

use strict;
use warnings;
use Data::Dump 'pp';

while(<DATA>)
  {
  /RepeatingGroup\s*=\s*
    (?<GroupID>\b\S+\b)\s*
    (?=.*(?<Flatten>\bFlatten\b))?
    (?=.*(?<Direction>\b(in|out)\b))?
    /x or next;
  print;
  pp \%+;
  }

__DATA__
RepeatingGroup = Waiver, Flatten, out
RepeatingGroup = Waiver, out
RepeatingGroup = Waiver, out, Flatten
RepeatingGroup = Waiver , in
RepeatingGroup = Waiver , Flatten