%map =
   map
   { m/^ default_ (option_.+) $/x
     ? ( $1 => $def{ $_ } )
     : ()
   }
   keys %def ;

@s{ keys %map } = values %map;

##</code><code>##

sub simple_fill
{
  my ( $save , %def ) = @_;

  for ( keys %def )
  {
    my ( $opt ) = ( $_ =~ m/^ default_ (option_.+) $/x )
      or next;

    $save->{ $opt } = $def{ $_ };
  }

  return;
}