Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl-Sensitive Sunglasses

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
You just hit the problem with inheritance - you're extending the class, which means you're tied to its implementation details.
With traditional, hash-based objects, you are right. And that's true for most of the implementations based on a Class::* module of CPAN, including Class::Std as well. And even the new inside out based class being promoted here on Perlmonks last week.

But the pure, not on a module depending, inside-out technique deals with inheritance perfectly. It can inherit from any implementation - and if inherited from, the inheritee can use whatever implementation it wants as well. Of course, if A inherits from B, B inherits from C, and B is using an inside-out technique, but A and C don't, C might still dictate how A is implemented.

#!/usr/bin/perl use strict; use warnings; package HashBased; sub new { my $class = shift; return bless {@_}, $class; } sub noise { my $self = shift; printf "The %s goes %s!\n", $self->{name}, $self->{sound} } sub name { my $self = shift; return $self->{name}; } package InsideOut; { use Scalar::Util 'refaddr'; my %legs; our @ISA = 'HashBased'; sub new { my $class = shift; my $legs = pop; my $obj = bless $class->SUPER::new(@_), $class; $legs{refaddr $obj} = $legs; return $obj; } sub show_legs { my $self = shift; printf "The %s has %d legs\n", $self->name, $legs{refaddr $sel +f}; } sub DESTROY { my $self = shift; delete $legs{$self} } } package main; my $dog = InsideOut->new(name => 'dog', sound => 'bark', 4); my $bird = InsideOut->new(name => 'bird', sound => 'peep', 2); $dog->noise; $dog->show_legs; $bird->noise; $bird->show_legs; __END__ The dog goes bark! The dog has 4 legs The bird goes peep! The bird has 2 legs
As you can see, the super class is using hash-based objects. But that doesn't prevent an inside-out based class to inherit from it. And you could even inherit from that class and use a hash-based implementation if you want to do so.
Perl --((8:>*

In reply to Re^2: How to use Inheritance with Inside-Out Classes and Hash Based Classes by Perl Mouse
in thread How to use Inheritance with Inside-Out Classes and Hash Based Classes by ghenry

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or or How to display code and escape characters are good places to start.
Log In?

What's my password?
Create A New User
Domain Nodelet?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others having an uproarious good time at the Monastery: (7)
As of 2022-05-20 08:41 GMT
Find Nodes?
    Voting Booth?
    Do you prefer to work remotely?

    Results (73 votes). Check out past polls.