And just to emphazise TIMTOWTDI:

$drink = 'unknown';
$drink = 'non alky' if $punter eq 'coffee';
$drink = 'alky' if $punter eq 'beer';
$drink = 'proper alky' if $punter eq 'whisky'
[download]

or (kind of ugly)

$drink = $punter eq 'coffee'?'non alky':$punter eq 'beer'?'alky':$punt
+er eq 'whisky'?'proper alky':'unknown';
[download]