my %lookup = ( # no longer a dispatch
   g6 => 1,
   g7 => 1,
   g8 => 1,
   g9 => 1,
   g0 => 0.5,
# ...
   );

my $total = 10;
$total += exists($lookup{'g6'})? $lookup{'g6'} : 0;

print $total, "\n";