if    ($punter eq 'coffee') { $drink = 'non alky';    }
elsif ($punter eq 'beer'  ) { $drink = 'alky';        }
elsif ($punter eq 'whisky') { $drink = 'proper alky'; }
else                        { $drink = 'unknown';     }

##</code><code>##

my %lookup = (
   'coffee' => 'non alky',
   'beer'   => 'alky',
   'whisky' => 'proper alky',
);

if (exists $lookup{$punter}) {
   $drink = $lookup{$punter};
} else {
   $drink = 'unknown';
}