Usually, when you need to create a subroutine that returns different values
in different contexts (list, scalar, or void), you write something like:

sub get_server_status {
my ($server_ID) = @_;

# Acquire server data somehow...
my %server_data = _ascertain_server_status($server_ID);

# Return different components of that data,
# depending on call context...
if (wantarray()) {
return @server_data{ qw(name uptime load users) };
}
if (defined wantarray()) {
return $server_data{load};
}
if (!defined wantarray()) {
carp 'Useless use of get_server_status() in void context';
return;
}
else {
croak q{Bad context! No biscuit!};
}
}

That works okay, but the code could certainly be more readable. In its
simplest usage, this module makes that code more readable by providing
three subroutines--'LIST()', 'SCALAR()', 'VOID()'--that are true only when
the current subroutine is called in the corresponding context:

use Contextual::Return;

sub get_server_status {
my ($server_ID) = @_;

# Acquire server data somehow...
my %server_data = _ascertain_server_status($server_ID);

# Return different components of that data
# depending on call context...
if (LIST) { return @server_data{ qw(name uptime load users) } }
if (SCALAR) { return $server_data{load} }
if (VOID) { print "$server_data{load}\n" }
else { croak q{Bad context! No biscuit!} }
}