Learning Perl Objects, References, and Modules

Learning Perl Objects, References, and Modules By Randal L. Schwartz
With Tom Phoenix
June 2003
Pages: 224

| Table of Contents | Index | Sample Chapter | Colophon

Chapter 1 Introduction
1. What Should You Know Already?
2. What About All Those Footnotes?
3. What's with the Exercises?
4. What if I'm a Perl Course Instructor?
Chapter 2 Building Larger Programs
1. The Cure for the Common Code
2. Inserting Code with eval
3. Using do
4. Using require
5. require and @INC
6. The Problem of Namespace Collisions
7. Packages as Namespace Separators
8. Scope of a Package Directive
9. Packages and Lexicals
10. Exercises
Chapter 3 Introduction to References
1. Performing the Same Task on Many Arrays
2. Taking a Reference to an Array
3. Dereferencing the Array Reference
4. Dropping Those Braces
5. Modifying the Array
6. Nested Data Structures
7. Simplifying Nested Element References with Arrows
8. References to Hashes
9. Exercises
Chapter 4 References and Scoping
1. More than One Reference to Data
2. What if That Was the Name?
3. Reference Counting and Nested Data Structures
4. When Reference Counting Goes Bad
5. Creating an Anonymous Array Directly
6. Creating an Anonymous Hash
7. Autovivification
8. Autovivification and Hashes
9. Exercises
Chapter 5 Manipulating Complex Data Structures
1. Using the Debugger to View Complex Data
2. Viewing Complex Data with Data::Dumper
3. Storing Complex Data with Storable
4. The map and grep Operators
5. Using map
6. Applying a Bit of Indirection
7. Selecting and Altering Complex Data
8. Exercises
Chapter 6 Subroutine References
1. Referencing a Named Subroutine
2. Anonymous Subroutines
3. Callbacks
4. Closures
5. Returning a Subroutine from a Subroutine
6. Closure Variables as Inputs
7. Closure Variables as Static Local Variables
8. Exercise
Chapter 7 Practical Reference Tricks
1. Review of Sorting
2. Sorting with Indices
3. Sorting Efficiently
4. The Schwartzian Transform
5. Recursively Defined Data
6. Building Recursively Defined Data
7. Displaying Recursively Defined Data
8. Exercises
Chapter 8 Introduction to Objects
1. If We Could Talk to the Animals...
2. Introducing the Method Invocation Arrow
3. The Extra Parameter of Method Invocation
4. Calling a Second Method to Simplify Things
5. A Few Notes About @ISA
6. Overriding the Methods
7. Starting the Search from a Different Place
8. The SUPER Way of Doing Things
9. What to Do with @_
10. Where We Are So Far...
11. Exercises
Chapter 9 Objects with Data
1. A Horse Is a Horse, of Course of Course—or Is It?
2. Invoking an Instance Method
3. Accessing the Instance Data
4. How to Build a Horse
5. Inheriting the Constructor
6. Making a Method Work with Either Classes or Instances
7. Adding Parameters to a Method
8. More Interesting Instances
9. A Horse of a Different Color
10. Getting Your Deposit Back
11. Don't Look Inside the Box
12. Faster Getters and Setters
13. Getters That Double as Setters
14. Restricting a Method to Class-Only or Instance-Only
15. Exercise
Chapter 10 Object Destruction
1. Nested Object Destruction
2. Beating a Dead Horse
3. Indirect Object Notation
4. Additional Instance Variables in Subclasses
5. Using Class Variables
6. Weakening the Argument
7. Exercise
Chapter 11 Some Advanced Object Topics
1. UNIVERSAL Methods
2. Testing Your Objects for Good Behavior
3. AUTOLOAD as a Last Resort
4. Using AUTOLOAD for Accessors
5. Creating Getters and Setters More Easily
6. Multiple Inheritance
7. References to Filehandles
8. Exercise
Chapter 12 Using Modules
1. Sample Function-Oriented Interface: File::Basename
2. Selecting What to Import
3. Sample Object-Oriented Interface: File::Spec
4. A More Typical Object-Oriented Module: Math::BigInt
5. The Differences Between OO and Non-OO Modules
6. What use Is Doing
7. Setting the Path at the Right Time
8. Importing with Exporter
9. @EXPORT and @EXPORT_OK
10. Exporting in a Primarily OO Module
11. Custom Import Routines
12. Exercise
Chapter 13 Writing a Distribution
1. Starting with h2xs
2. Looking at the Templates
3. The Prototype Module Itself
4. Embedded Documentation
5. Controlling the Distribution with Makefile.PL
6. Alternate Installation Locations (PREFIX=...)
7. Trivial make test
8. Trivial make install
9. Trivial make dist
10. Using the Alternate Library Location
11. Exercise
Chapter 14 Essential Testing
1. What the Test Harness Does
2. Writing Tests with Test::Simple
3. Writing Tests with Test::More
4. Conditional Tests
5. More Complex Tests (Multiple Test Scripts)
6. Testing Things That Write to STDOUT and STDERR
7. Exercise
Chapter 15 Contributing to CPAN
1. The Comprehensive Perl Archive Network
2. Getting Prepared
3. Preparing Your Distribution
4. Uploading Your Distribution
5. Announcing the Module
6. Testing on Multiple Platforms
7. Consider Writing an Article or Giving a Talk
8. Exercise

Appendix A Answers to Exercises
1. Answers for Chapter 2
2. Answers for Chapter 3
3. Answers for Chapter 4
4. Answers for Chapter 5
5. Answer for Chapter 6
6. Answers for Chapter 7
7. Answers for Chapter 8
8. Answer for Chapter 9
9. Answer for Chapter 10
10. Answer for Chapter 11
11. Answer for Chapter 12
12. Answers for Chapters 13-15
Colophon

Return to Learning Perl Objects, References, and Modules

Table of Contents

Chapter 1 Introduction

What Should You Know Already?

What About All Those Footnotes?

What's with the Exercises?

What if I'm a Perl Course Instructor?

Chapter 2 Building Larger Programs

The Cure for the Common Code

Inserting Code with eval

Using do

Using require

require and @INC

The Problem of Namespace Collisions

Packages as Namespace Separators

Scope of a Package Directive

Packages and Lexicals

Exercises

Chapter 3 Introduction to References

Performing the Same Task on Many Arrays

Taking a Reference to an Array

Dereferencing the Array Reference

Dropping Those Braces

Modifying the Array

Nested Data Structures

Simplifying Nested Element References with Arrows

References to Hashes

Exercises

Chapter 4 References and Scoping

More than One Reference to Data

What if That Was the Name?

Reference Counting and Nested Data Structures

When Reference Counting Goes Bad

Creating an Anonymous Array Directly

Creating an Anonymous Hash

Autovivification

Autovivification and Hashes

Exercises

Chapter 5 Manipulating Complex Data Structures

Using the Debugger to View Complex Data

Viewing Complex Data with Data::Dumper

Storing Complex Data with Storable

The map and grep Operators

Using map

Applying a Bit of Indirection

Selecting and Altering Complex Data

Exercises

Chapter 6 Subroutine References

Referencing a Named Subroutine

Anonymous Subroutines

Callbacks

Closures

Returning a Subroutine from a Subroutine

Closure Variables as Inputs

Closure Variables as Static Local Variables

Exercise

Chapter 7 Practical Reference Tricks

Review of Sorting

Sorting with Indices

Sorting Efficiently

The Schwartzian Transform

Recursively Defined Data

Building Recursively Defined Data

Displaying Recursively Defined Data

Exercises

Chapter 8 Introduction to Objects

If We Could Talk to the Animals...

Introducing the Method Invocation Arrow

The Extra Parameter of Method Invocation

Calling a Second Method to Simplify Things

A Few Notes About @ISA

Overriding the Methods

Starting the Search from a Different Place

The SUPER Way of Doing Things

What to Do with @_

Where We Are So Far...

Exercises

Chapter 9 Objects with Data

A Horse Is a Horse, of Course of Course—or Is It?

Invoking an Instance Method

Accessing the Instance Data