package Scraper;

sub new {
  my( $pkg, $strategy_class ) = @_;
  bless {
    strategy_class => $strategy_class, 
  }, $pkg
}

sub scrape {
  my $self = shift;
  my $config_data = $self->{'strategy_class'}->config_data();
  # ... proceed to scrape using this config data
}


package Scraper::Yahoo;

# as a strategy of Scraper, this class only needs to implement those methods
# a Scraper will call.

sub config_data {
  return(
    starting_page  => 'www.yahoo.com/foo/',
    some_regex     => qr/foo(.*?)bar/,
    html_tree_spec => [ '_tag', 'div', 'id', 'headlines' ],
  );
}

. . .

package main;

# pass the strategy class name to the constructor:
my $yahoo_scraper = new Scraper 'Scraper::Yahoo';