my (%child, @ancestor, $node, $left, $right);
$node = $1, $left = $2, $right = $3 if(/(.+?): (.+?), (.+)/);
$child{$node} = $left . ' ' . $right; 	
push @ancestor, $node;

if($left =~ /^\w/ && $right =~ /^\[/){
		my $children_node = child_check($child{$right});
		$child{$node} = $left . ' ' . $children_node;
		# $right wird vom Array @ancestor entfernt
		@ancestor = grep !/^\Q$right\E$/, @ancestor;
}

foreach(@ancestor){
	my $vater_id = $_;
	my $descendant = $child{$_};
	print "$_:\t$descendant\n";
}
sub child_check{
	my $string = shift;
	my @arr_ance = split(/ /, $string);
	my @all_children;
	foreach my $ance(@arr_ance){
		if (defined $child{$ance}) {
			my @descendants = split(/ /, $child{$ance});
			foreach my $desc(@descendants){
				if (defined $child{$desc}) {
					child_check($child{$desc});
				}
				else{
					push @all_children, $desc;
				}
			}		
		}
		else{
			push @all_children, $string;
		}	
	}	
	my $join_children = join(', ', @all_children);
	return $join_children;
}