Target audience:
Perl programmers who have a basic familiarity with simple OO Perl (i.e. blessed hashes).

What attendees will learn:
This tutorial will show you how to build on the basic object-oriented Perl techniques you already know and unlock more of the power of Perl's OO capabilities.

You will learn:

• how to use pseudo-hashes and the standard fields.pm and base.pm modules;
• how (and when) to bless arrays and scalars;
• three different ways to implement data hiding for Perl objects (including the Tie::SecureHash module);
• how Perl implements inheritance and polymorphism (and how you can change the rules of either);
• how to simulate scalars and hashes using ties;
• the features (and traps) of operator overloading in Perl;
• easy ways to build complete classes (semi-)automatically;

Tutorial outline:

• Revision of Perl OO basics
  • packages, references, blessing
  • the three rules
• Non-hash-based objects
  • arrays as objects
  • scalars as objects
• Pseudo-hashes
  • what they are, how to use them as objects
  • the fields.pm module
  • compile-time type checking
• Automating class construction
  • Class::Struct
  • Other modules
• Inheritance
  • revision of concepts
  • how they work in Perl
  • @ISA, isa(), can(), SUPER
  • tricks with inherited constructors and destructors
  • abstract methods
  • attribute collisions
  • inheritance and pseudohashes: the base.pm module
• Polymorphism
  • what it is
  • when and how to use it
• Encapsulation
  • the pros and cons of data hiding
  • encapsulation via closures
  • encapsulation via scalars
  • encapsulation via the Tie::SecureHash module
• Ties
  • mechanism
  • simulating scalars
  • simulating hashes
• Operator overloading
  • overview and limitations of mechanism
  • overloading operations, conversions, and constants
  • problems with references