I have looked in object oriented section Q&A for something like this, but didn't quite find the slant I am looking for.

When I create a child class, how should I ensure that the parent class constructor is properly called?

I am currently doing something like this - is there a better way?

use strict;
# This should do ALL the _initXXX()s 
# even though myGrandChild does not know
# about _initParent() or _initChild()!
my $it = myGrandChild->new('a','b','c');


#----------------------------------
package myParent;
our @ISA;
sub new {
  my $class = shift;
  my $self = $ISA[0] ? $ISA[0]->new(@_) : {};
  bless $self,$class;
  $self->_initParent(@_);
  return $self;
}
sub _initParent {
  my $self = shift;
  print "_initParent @_  [ISA: @ISA]\n";
}

#----------------------------------
package myChild;
our @ISA;
use base qw(myParent);

sub new {
  my $class = shift;
  my $self = $ISA[0] ? $ISA[0]->new(@_) : {};
  bless $self,$class;
  $self->_initChild(@_);
  return $self;
}
sub _initChild {
  my $self = shift;
  print "_initChild @_  [ISA: @ISA]\n";
}

#----------------------------------
package myGrandChild;
our @ISA;
use base qw(myChild);
sub new {
  my $class = shift;
  my $self = $ISA[0] ? $ISA[0]->new(@_) : {};
  bless $self,$class;
  $self->_initGrandChild(@_);
  return $self;
}
sub _initGrandChild {
  my $self = shift;
  print "_initGrandChild @_  [ISA: @ISA]\n";
}
#----------------------------------
[download]

Obviously calling _initXXX()s is a facet of this being a trivial example - a number of classes in our library do more complex things when created. Also, they are not all in-house, so enforcing an additional naming standard - i.e. assuming that there is a $self->SUPER::_init() does not work.

Regards,

Jeff

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