package Person;
use XML::Parser;

sub new {
 my $class = shift;
 my $id = shift;

 my $self = { id => $id };
 bless $self;

 ## now, set up XML::Parser;
 $parser->parsefile ("/path/to/some/file/$id.xml");
 return $self;
}

# standard XML::Parser stuff here
sub startElement {
 my( $parseinst, $element, %attrs ) = @_;

 if ($element eq "TAG") {
   my $property = $attrs{Property};
   ## HOW TO SET $self->{property} from here?
 }
}