my %dispatcher => (
      \$quux => [ 
                            sub {
                              return 0 unless $_[0] =~ ${$_[1]}; 
                              ${$_[3]} =~ s/${$_[1]}/${$_[2]}/;
                              return $_[3];
                            },
                            qr{bar},
                            qq{foo},
                ],
    );

    $dispatcher{$key} -> [0] -> 
      ($file, $dispatcher{$key} -> [0] -> [1], $dispatcher{$key} -> [0] -> [1]);