Re: Calling SUPER::constructor in the constructor

[James Edward Gray II]

On Feb 1, 2004, at 1:10 AM, R. Joseph Newton wrote:

To answer your immediate
question, there is a way to call functions of the parent, but with 
another
step in indeirection:
$child_class->SUPER->new.

You should rarely need this though.  Any attributes [ie hash members] 
of the
parent class that are relevant in your child object can simply be 
addressed
thorugh the constructor of the child class.
and

Well, that worked, but note that the following constructor for the 
MyChild
object worked just as well:

sub new {
  my $class = shift;
  my $name = shift;
  my $age = shift;
  my $self = {};
  bless $self, $class;
  $self->{name} = $name;
  $self->{age} =  $age;
  return $self;
}
and the name and age attributes set through the child constructor were 
just
as available to the bemoan_age accessor provided by the base class.  
I'm not
sure I see any benefit to calling SUPER:: methods except in cases 
where a
parent method is overshadowed but still needed.
I think SUPER is a little more important than you give it credit for.  
I would say it's very common to use in a child's constructor.

I find your suggestion of duplicating the parent's construction scary 
OO thinking and I hope we're assuming you wrote both objects, at the 
very least.  Still, one day you're going to change one and forget the 
other...  Aren't we always telling people not to "reinvent the wheel" 
and to "use modules"?  It's really the same issue, I think.  I would 
much rather see people using SUPER than rewriting code.

SUPER is also quite handy when you're overriding a method, but just 
want to extend its functionality.  Make the call then do the rest.  
Simple, flexible, powerful.

James

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