sub hash {
  my %param = @_;  # I hope I'm remembering this right...
  print $param{uno}, "\n";
}

##</code><code>##

hash(  { uno => 'one',
         dos => 'two',
         tres => 'three',
       }
    );

sub hash {
   my ($param) = @_;
   print $param->{uno}, "\n";
}