my %action = (
  qr/^give (.*)(?:\s+(to) (.+)))$/ => \&give_to,
  qr/^go (.*)$/ => \&go_to,
  qr/^take (\w+)$/ => \&take_item,
);

while (<>) {
  my $matched;
  for my $pattern (keys %action) {
    if (/$pattern/) {
      $action{$pattern}->();
      $matched++;
      last;
    };
  };
  print "I didn't understand what you meant by '$_'.\n";
};