在perl中无法重载构造函数

Question

OOP perl的新手......第一个程序,不是过载构造函数的打包.我尝试了很多东西,可能是我还缺少一些东西!

基类:

#!/usr/bin/perl
use strict;
package Person;
sub new
{
my($class)=shift;
my($self)={ 
        _name=>shift,
        _sname=>shift,
};
bless $self, $class;
return $self;
}       
1;  

派生类:

#!/usr/bin/perl
package Employee;
use strict;
use Person;
our @ISA = qw(Person);
sub new
{
my($class)=@_;
my($self)=$class->SUPER::new($_[1],$_[2]);
my $self1={
        _id=>$_[3],
        _sal=>$_[4],
};
bless $self1,$class;
return ($self);
}
1;

主程序:

#!/usr/bin/perl
use strict;
use Data::Dumper;
use Employee;

sub main
{
my($obj)=Employee->new("abc","def","515","10");
print Dumper $obj;
}
main();

我无法获得基类类成员的值.没有得到我想念的程序.帮帮我.

Answer 1

$self1在派生的构造函数中不需要调用对象.你应该说:

sub new {
    my($class)=@_;
    my($self)=$class->SUPER::new($_[1],$_[2]);
    $self->{_id} = $_[3];
    $self->{_sal} = $_[4];
    # no need to bless -- $self is already blessed correctly in SUPER::new
    return ($self);
}