perl 访问类方法的几种方式

[root@wx03 test]# cat Horse.pm 
package Horse;
use base qw(Critter);
sub new {
my $invocant = shift;
my $class = ref($invocant) || $invocant;
my $self = {
color => "bay",
legs => 4,
owner => undef,
@_, # 覆盖以前的属性
};
return bless $self, $class;
#return  $self;
};
sub sum1 {
       $self=shift;
       my $a=shift;
       my $b=shift;
       return $a + $b + 7;
};

our @arr=qw/1 2 3 4 5 6 7/;
our %h1=(1,2,3,4,5,6,7,8);
1;
[root@wx03 test]# cat Critter.pm 
package Critter;
sub new {
    my $self = {};
    my $invocant = shift;    
my $class = ref($invocant) || $invocant;
	my ($name)=@_;    
      my $self = {    
         "name" =>$name    
                 };  
    bless $self, $class; # Use class name to bless() reference
    return $self;

};

sub sum2 {
       $self=shift;
       my $a=shift;
       my $b=shift;
       return $a + $b;
};


sub fun1 {
       $self=shift;
       my $a=shift;
       my $b=shift;
       return $a / $b;
}
1;
[root@wx03 test]# cat t10.pl 
unshift(@INC,"/root/test"); 
use Horse;;
$ua=Horse->new();
print "111111111111
";
$code=Horse->sum1(4,5);

print "$str is $code
";
print "222222222222
";

$code=Horse->sum2(4,5);
print "$str is $code
";

print "33333333333333
";
print Horse::sum1($ua,1,2);
print "
";



print "4444444444444444
";
print Critter::sum2($ua,1,2);
print "
";


print "55555555555555555
";
print $ua->sum1(4,5);
print "
";


print "66666666666666666
";
print $ua->sum2(4,5);
print "
";