Intermediate Perl（影印版）

Foreword . xiii

Preface xv

1. Introduction 1

What Should You Know Already? 2

What About All Those Footnotes? 2

What’s with the Exercises? 2

What If I’m a Perl Course Instructor? 3

2. Intermediate Foundations 4

List Operators 4

Trapping Errors with eval 8

Dynamic Code with eval 9

Exercises 10

3. Using Modules 11

The Standard Distribution 11

Using Modules 12

Functional Interfaces 12

Selecting What to Import 13

Object-Oriented Interfaces 14

A More Typical Object-Oriented Module: Math::BigInt 15

The Comprehensive Perl Archive Network 15

Installing Modules from CPAN 16

Setting the Path at the Right Time 17

Exercises 19

4. Introduction to References 21

Performing the Same Task on Many Arrays 21

Taking a Reference to an Array 23

Dereferencing the Array Reference 24

Getting Our Braces Off 26

Modifying the Array 26

Nested Data Structures 27

Simplifying Nested Element References with Arrows 29

References to Hashes 30

Exercises 32

5. References and Scoping34

More Than One Reference to Data 34

What If That Was the Name? 35

Reference Counting and Nested Data Structures 36

When Reference Counting Goes Bad 38

Creating an Anonymous Array Directly 40

Creating an Anonymous Hash 42

Autovivification 44

Autovivification and Hashes 47

Exercises 48

6. Manipulating Complex Data Structures 50

Using the Debugger to View Complex Data 50

Viewing Complex Data with Data::Dumper 54

YAML 56

Storing Complex Data with Storable 57

Using the map and grep Operators 59

Applying a Bit of Indirection 59

Selecting and Altering Complex Data 60

Exercises 62

7. Subroutine References63

Referencing a Named Subroutine 63

Anonymous Subroutines 68

Callbacks 70

Closures 70

Returning a Subroutine from a Subroutine 72

Closure Variables as Inputs 75

Closure Variables as Static Local Variables 75

Exercise 77

8. Filehandle References. 79

The Old Way 79

The Improved Way 80

The Even Better Way 81

IO::Handle 82

Directory Handle References 86

Exercises 87

9. Practical Reference Tricks 89

Review of Sorting 89

Sorting with Indices 91

Sorting Efficiently 92

The Schwartzian Multi-Level Sort with the Recursively Defined ata 95

Building Recursively Defined Data 96

Displaying Recursively Defined Data 98

Exercises 99

10. Building Larger Programs 101

The Cure for the Common Code 101

Inserting Code with eval 102

Using do 103

Using require 105

require and @INC 106

The Problem of Namespace Collisions 109

Packages as Namespace Separators 110

Scope of a Package Directive 112

Packages and Lexicals 113

Exercises 113

11. Introduction to Objects115

If We Could Talk to the Animals... 115

Introducing the Method Invocation Arrow 117

The Extra Parameter of Method Invocation 118

Calling a Second Method to Simplify Things 119

A Few Notes About @ISA 120

Overriding the Methods 121

Starting the Search from a Different Place 123

The SUPER Way of Doing Things 124

What to Do with @_ 124

Where We Are So Far... 124

Exercises 125

12. Objects with Data 126

A Horse Is a Horse, of Course of Course—or Is It? 126

Invoking an Instance Method 127

Accessing the Instance Data 128

How to Build a Horse 128

Inheriting the Constructor 129

Making a Method Work with Either Classes or Instances ..130

Adding Parameters to a Method 131

More Interesting Instances 132

A Horse of a Different Color 133

Getting Our Deposit Back 133

Don’t Look Inside the Box 135

Faster Getters and Setters 136

Getters That Double as Setters 136

Restricting a Method to Class-Only or Instance-Only 137

Exercise 137

13. Object Destruction 139

Cleaning Up After Yourself 139

Nested Object Destruction 141

Beating a Dead Horse 144

Indirect Object Notation 145

Additional Instance Variables in Subclasses 147

Using Class Variables 149

Weakening the Argument 150

Exercise 152

14. Some Advanced Object Topics 154

UNIVERSAL Methods 154

Testing Our Objects for Good Behavior 155

AUTOLOAD as a Last Resort 156

Using AUTOLOAD for Accessors 157

Creating Getters and Setters More Easily 158

Multiple Inheritance 160

Exercises 161

15. Exporter 162

What use Is Doing 162

Importing with Exporter 163

@EXPORT and @EXPORT_OK 164

%EXPORT_TAGS 165

xporting in a Primarily OO Module 166

Custom Import Routines 168

Exercises 169

16. Writing a Distribution171

There’s More Than One Way To Do It 172

Using h2xs 173

Embedded Documentation 179

Controlling the Distribution with Makefile.PL 183

Alternate Installation Locations (PREFIX=...) 184

Trivial make test 185

Trivial make install 186

Trivial make dist 186

Using the Alternate Library Location 187

Exercise 188

17. Essential Testing 189

More Tests Mean Better Code 189

A Simple Test Script 190

The Art of Testing 191

The Test Harness 193

Writing Tests with Test::More 195

Testing Object-Oriented Features 197

A Testing To-Do List 199

Skipping Tests 200

More Complex Tests (Multiple Test Scripts) 201

Exercise 201

18. Advanced Testing . 203

Testing Large Strings 203

Testing Files 204

Testing STDOUT or STDERR 205

Using Mock Objects 208

Testing POD 209

Coverage Testing 210

Writing Your Own Test::* Modules 211

Exercises 214

19. Contributing to CPAN. 216

The Comprehensive Perl Archive Network 216

Getting Prepared 216

Preparing Your Distribution 217

Uploading Your Distribution 218

Announcing the Module 219

Testing on Multiple Platforms 219

Consider Writing an Article or Giving a Talk 220

Exercise 220

Appendix: Answers to Exercises 221

Index ... 249