PerlSchool · Perl School Publishing

Design Patterns
in Modern Perl

Practical Patterns for Everyday Perl - all 23 Gang of Four patterns, implemented in real, runnable Perl.

Buy on Leanpub - from $7.99 Buy on Amazon Paperback

294 pages 23 GoF patterns 3 OO styles: bless, Moo, class PDF, EPUB & paperback

Cover of Design Patterns in Modern Perl by Mohammad Sajid Anwar

About the book

Patterns as theory made tedious. This book makes them runnable.

Design Patterns in Modern Perl shows how classic object-oriented patterns look in today's Perl. Using core Perl, Moo, and Object::Pad, Mohammad Sajid Anwar builds real, tested examples, helping you choose patterns sensibly and write cleaner, more maintainable code.

Every chapter follows the same shape: the problem the pattern solves, a worked example, complete implementations across three object systems, and the unit tests and benchmarks to go with them.

01 Traditional bless, via Class::Mite
02 Moo, the lightweight modern standard
03 Core class / Object::Pad, Perl's newest OO syntax

Patterns covered23

Creational5

Structural7

Behavioural11

FormatPDF / EPUB / Paperback

Table of contents

What's inside

The three pattern families, laid out the way the book builds them - one package per family, one chapter per pattern.

package Creational;

01 Abstract Factory p.41
02 Builder p.57
03 Factory Method p.74
04 Prototype p.84
05 Singleton p.96

package Structural;

01 Adapter p.103
02 Bridge p.117
03 Composite p.129
04 Filter p.136
05 Decorator p.150
06 Facade p.161
07 Proxy p.170

package Behavioural;

01 Chain of Responsibility p.181
02 Command p.192
03 Interpreter p.204
04 Iterator p.212
05 Mediator p.222
06 Memento p.232
07 Observer p.240
08 State p.254
09 Strategy p.263
10 Template p.272
11 Visitor p.281

use FrontMatter; // Dedication, Foreword, Introduction & Getting Started

Dedicationp.7

Acknowledgementsp.9

Forewordp.11

Introduction: Historyp.15

What is a Design Pattern?p.16

Why are Design Patterns useful?p.16

What problems do they solve?p.17

The Gang of Fourp.18

Who should read this?p.18

Choice of OOP Frameworksp.21

Environment Setupp.29

Introduction to Class::Mitep.31

Test Driven Developmentp.36

About the Bookp.293

OOP Frameworks

Pattern Implementation Matrix

Below is a chart listing the implementations of each design pattern in the various OOP frameworks. Only four of the patterns were implemented using the experimental class feature.

Name	bless	Moo	Object::Pad	class
Abstract Factory	✓	✓	✓
Builder	✓	✓	✓
Factory Method	✓	✓	✓
Prototype	✓	✓		✓
Singleton	✓	✓		✓
Adapter	✓	✓	✓
Bridge	✓	✓	✓
Composite	✓	✓		✓
Filter	✓	✓	✓
Decorator	✓	✓	✓
Facade	✓	✓	✓
Proxy	✓	✓	✓
Chain of Responsibility	✓	✓	✓
Command	✓	✓	✓
Interpreter	✓	✓	✓
Iterator	✓	✓	✓
Mediator	✓	✓	✓
Memento	✓	✓		✓
Observer	✓	✓	✓
State	✓	✓	✓
Strategy	✓	✓	✓
Template	✓	✓	✓
Visitor	✓	✓	✓

The author

Mohammad Sajid Anwar

Mohammad Sajid Anwar is an India-born software developer now based in the United Kingdom. His career in technology began in Jamshedpur and later took him to Mumbai before he settled in London in 2000, building his expertise through the dot-com boom and its aftermath. With a background in mathematics, he has focused much of his technical work on elegant, reliable solutions in Perl.

Sajid is a prolific CPAN author (PAUSE id MANWAR), known especially for the Map::Tube ecosystem for modelling urban transport networks, extensive calendrical libraries, and tools for the Dancer2 web framework. In 2023 he received the White Camel Award for outstanding service to the Perl community. He founded and runs The Weekly Challenge and has served as a co-editor of the Perl Weekly newsletter for more than six years.

GitHub / manwar CPAN / MANWAR The Weekly Challenge manwar.org

Get the book

Bring the Gang of Four into your Perl.

DRM-free PDF & EPUB on Leanpub, or a paperback on Amazon.

Buy on Leanpub Buy on Amazon Paperback