perl 当前包会覆盖父类的同名方法

12.5.2 访问被覆盖的方法:

当一个类定义一个方法，那么该子过程覆盖任意基类中同名的方法。

[root@wx03 test]# cat Horse.pm
package Horse;
our @ISA = "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;
};
sub sum {
       $self=shift;
       my $a=shift;
       my $b=shift;
       return $a + $b + 7;
};
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 sum {
       $self=shift;
       my $a=shift;
       my $b=shift;
       return $a + $b;
};
1;
[root@wx03 test]# cat t6.pl
unshift(@INC,"/root/test");
use Horse;;
use base qw(Critter);
require Critter;
use Data::Dumper;
$ed = Horse->new; # 四腿湾马
print $ed->sum(4,5);
print "\n";
print $ed->sum(4,5)
[root@wx03 test]# perl t6.pl
16
16[root@wx03 test]# 

会覆盖基类的相同方法;