Re: Access package variables of subclass from base class

In C++ parlance you should use a 'pure virtual' member function. In Perl that just means that you assume the derived class will provide a member. Consider:

use strict;
use warnings;

package BaseClass;

sub new {
    return bless {}, shift;
}


sub useVirtualX {
    my ($self) = @_;

    return $self->GetX ();
}

1;

package main;

use base 'BaseClass';

my $obj = main->new ();
my $privateX = 42;

print $obj->useVirtualX ();


sub new {
    return shift->SUPER::new ();
}


sub GetX {
    return $privateX;
}
[download]

Prints:

42
[download]

True laziness is hard work

Comment on Re: Access package variables of subclass from base class Select or Download Code

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Re^2: Access package variables of subclass from base class by Anonymous Monk on Mar 04, 2009 at 12:36 UTC
`sub GetX { my ($self) = @_; my $subc = ref($self) ; if ( $subc ne __PACKAGE__ ) { croak "do not call $subc\::SUPER->GetX"; } else { croak "GetX must be implemented by subclass"; } }` [download]	[reply] [d/l]