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\n";
$code=Horse->sum1(4,5);print "\$str is $code\n";
print "222222222222\n";$code=Horse->sum2(4,5);
print "\$str is $code\n";print "33333333333333\n";
print Horse::sum1($ua,1,2);
print "\n";print "4444444444444444\n";
print Critter::sum2($ua,1,2);
print "\n";print "55555555555555555\n";
print $ua->sum1(4,5);
print "\n";print "66666666666666666\n";
print $ua->sum2(4,5);
print "\n";