>perl -wMstrict -le
"my $char_list = 'Exit Cassio; Enter Iago, Othello, and  others';
 ;;
 my @words = split /\W+/, $char_list;
 printf qq{'$_' } for @words;
 print '';
 ;;
 ;;
 my $not_player = qr{ (?! Enter | Exit) }xms;
 my $player = qr{ \b $not_player [[:upper:]] [[:lower:]]+ }xms;
 ;;
 my @players = $char_list =~ m{ $player }xmsg;
 printf qq{'$_' } for @players;
 print '';
 ;;
 ;;
 my @dramatis_personae = qw(Cassio Iago Othello);
 my ($character) =
   map qr{ \b (?: $_) \b }xms,
   join '|',
   @dramatis_personae
   ;
 ;;
 @players = $char_list =~ m{ $character }xmsg;
 printf qq{'$_' } for @players;
"
'Exit' 'Cassio' 'Enter' 'Iago' 'Othello' 'and' 'others'
'Cassio' 'Iago' 'Othello'
'Cassio' 'Iago' 'Othello'