#!/share/bin/perl -w

# Two hashes - one maps roles to players, the other maps
# players to roles.
# It is assumed that each player takes only one role.

# There are lots of ways to initialize a hash
# Element by element 
#$cast{"First witch"} = "Angie";
#$cast{"Second witch"} = "Karen";

# Or create a list literal and convert to hash (list assumed to
# be ( key value key value ....)
@cast = ("First witch", "Angie","Second witch", "Karen","Third witch", "Sonia",
	"Duncan","Peter","Macbeth", "Phillip", "Lady Macbeth", "Joan",
	 "Banquo", "John","Porter", "Neil",
	"Gentlewoman 3", "Holly");
# and if that gets a little opaque, there is another way
# %cast = ("First witch" => "Angie",
# "Donaldbain" => "Willy",
# "Menteith" => "Tim",
# "Gentlewoman 3" => "Holly");

%cast = @cast;

%players = reverse %cast;
while(1) {
	print 'Enter command:
1) Look up who plays role
2) Look up role played by actor
3) List roles
4) Quit
Command: ';
	$cmd = <STDIN>;
	if($cmd == 4) { last; }
	elsif($cmd == 3) {
		# keys gives a list of the keys in the hash
		@roles = keys %cast;
		# "foreach" loop through list
		for $role (@roles) { print $role, "\n"; }
		}
	elsif($cmd == 2) {
		print "Enter actor's name : ";
		$Player = <STDIN>;
		chomp($Player);
		# simple hash lookup operation
		$Role = $players{$Player};
		if($Role) { print "$Player plays the role $Role\n"; }
		else { print "$Player is resting for this production\n"; }
	}
	elsif($cmd == 1) {
		print "Enter role name : ";
		$Role = <STDIN>;
		chomp($Role);
		$Actor = $cast{$Role};
		if($Actor) { print "$Role is being performed by $Actor\n"; }
		else { print "$Role not recognized as part of cast\n"; }
	}
	else { print "Command not recognized\n"; }
}