book

Learning Perl Objects, References, and Modules

by Randal L. Schwartz, Tom Phoenix

June 2003

Beginner

224 pages

5h 51m

English

O'Reilly Media, Inc.

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Learning Perl Objects, References & Modules
A Note Regarding Supplemental Files
Foreword
Preface
Structure of This BookConventions Used in This BookComments and QuestionsAcknowledgments
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?
2. Building Larger Programs
The Cure for the Common CodeInserting Code with evalUsing doUsing requirerequire and @INCExtending @INCExtending @INC with PERL5LIBExtending @INC with -IThe Problem of Namespace CollisionsPackages as Namespace SeparatorsScope of a Package DirectivePackages and LexicalsExercisesExercise 1 [30 min]Exercise 2 [10 min]
3. Introduction to References
Performing the Same Task on Many ArraysTaking a Reference to an ArrayDereferencing the Array ReferenceDropping Those BracesModifying the ArrayNested Data StructuresSimplifying Nested Element References with ArrowsReferences to HashesExercisesExercise 1 [5 min]Exercise 2 [30 min]
4. References and Scoping
More than One Reference to DataWhat if That Was the Name?Reference Counting and Nested Data StructuresWhen Reference Counting Goes BadCreating an Anonymous Array DirectlyCreating an Anonymous HashAutovivificationAutovivification and HashesExercisesExercise 1 [5 min]Exercise 2 [30 min]
5. Manipulating Complex Data Structures
Using the Debugger to View Complex DataViewing Complex Data with Data::DumperStoring Complex Data with StorableThe map and grep OperatorsUsing mapApplying a Bit of IndirectionSelecting and Altering Complex DataExercisesExercise 1 [20 min]Exercise 2 [5 min]
6. Subroutine References
Referencing a Named SubroutineAnonymous SubroutinesCallbacksClosuresReturning a Subroutine from a SubroutineClosure Variables as InputsClosure Variables as Static Local VariablesExerciseExercise [30 min]

7. Practical Reference Tricks
Review of SortingSorting with IndicesSorting EfficientlyThe Schwartzian TransformRecursively Defined DataBuilding Recursively Defined DataDisplaying Recursively Defined DataExercisesExercise 1 [15 min]Exercise 2 [15 min]Exercise 3 [10 min]Exercise 4 [20 min]
8. Introduction to Objects
If We Could Talk to the Animals...Introducing the Method Invocation ArrowThe Extra Parameter of Method InvocationCalling a Second Method to Simplify ThingsA Few Notes About @ISAOverriding the MethodsStarting the Search from a Different PlaceThe SUPER Way of Doing ThingsWhat to Do with @_Where We Are So Far...ExercisesExercise 1 [20 min]Exercise 2 [40 min]
9. Objects with Data
A Horse Is a Horse, of Course of Course—or Is It?Invoking an Instance MethodAccessing the Instance DataHow to Build a HorseInheriting the ConstructorMaking a Method Work with Either Classes or InstancesAdding Parameters to a MethodMore Interesting InstancesA Horse of a Different ColorGetting Your Deposit BackDon’t Look Inside the BoxFaster Getters and SettersGetters That Double as SettersRestricting a Method to Class-Only or Instance-OnlyExerciseExercise [45 min]
10. Object Destruction
Nested Object DestructionBeating a Dead HorseIndirect Object NotationAdditional Instance Variables in SubclassesUsing Class VariablesWeakening the ArgumentExerciseExercise [45 min]
11. Some Advanced Object Topics
UNIVERSAL MethodsTesting Your Objects for Good BehaviorAUTOLOAD as a Last ResortUsing AUTOLOAD for AccessorsCreating Getters and Setters More EasilyMultiple InheritanceReferences to FilehandlesExerciseExercise [30 min]
12. Using Modules
Sample Function-Oriented Interface: File::BasenameSelecting What to ImportSample Object-Oriented Interface: File::SpecA More Typical Object-Oriented Module: Math::BigIntThe Differences Between OO and Non-OO ModulesWhat use Is DoingSetting the Path at the Right TimeImporting with Exporter@EXPORT and @EXPORT_OKExporting in a Primarily OO ModuleCustom Import RoutinesExerciseExercise [15 min]
13. Writing a Distribution
Starting with h2xsLooking at the TemplatesThe Prototype Module ItselfEmbedded DocumentationControlling the Distribution with Makefile.PLAlternate Installation Locations (PREFIX=...)Trivial make testTrivial make installTrivial make distUsing the Alternate Library LocationExerciseExercise [30 min]
14. Essential Testing
What the Test Harness DoesWriting Tests with Test::SimpleWriting Tests with Test::MoreConditional TestsMore Complex Tests (Multiple Test Scripts)Testing Things That Write to STDOUT and STDERRExerciseExercise [60 min]
15. Contributing to CPAN
The Comprehensive Perl Archive NetworkGetting PreparedPreparing Your DistributionUploading Your DistributionAnnouncing the ModuleTesting on Multiple PlatformsConsider Writing an Article or Giving a TalkExerciseExercise
A. Answers to Exercises
Answers for Chapter 2Exercise 1 (Exercise 1 [30 min])Exercise 2 (Exercise 2 [10 min])Answers for Chapter 3Exercise 1 (Exercise 1 [5 min])Exercise 2 (Exercise 2 [30 min])Answers for Chapter 4Exercise 1 (Exercise 1 [5 min])Exercise 2 (Exercise 2 [30 min])Answers for Chapter 5Exercise 1 (Exercise 1 [20 min])Exercise 2 (Exercise 2 [5 min])Answer for Chapter 6Exercise (Exercise [30 min])Answers for Chapter 7Exercise 1 (Exercise 1 [15 min])Exercise 2 (Exercise 2 [15 min])Exercise 3 (Exercise 3 [10 min])Exercise 4 (Exercise 4 [20 min])Answers for Chapter 8Exercise 1 (Exercise 1 [20 min])Exercise 2 (Exercise 2 [40 min])Answer for Chapter 9Exercise (Exercise [45 min])Answer for Chapter 10Exercise (Exercise [45 min])Answer for Chapter 11Exercise (Exercise [30 min])Answer for Chapter 12Exercise (Exercise [15 min])Answers for Chapters 13-15
Index
About the Authors
Colophon
Copyright

Overview

Perl is a versatile, powerful programming language used in a variety of disciplines, ranging from system administration to web programming to database manipulation. One slogan of Perl is that it makes easy things easy and hard things possible. This book is about making the leap from the easy things to the hard ones.Learning Perl Objects, References & Modules offers a gentle but thorough introduction to advanced programming in Perl. Written by the authors of the best-selling Learning Perl, this book picks up where that book left off. Topics include:

Packages and namespaces
References and scoping
Manipulating complex data structures
Object-oriented programming
Writing and using modules
Contributing to CPAN

Following the successful format of Learning Perl, each chapter in the book is designed to be small enough to be read in just an hour or two, ending with a series of exercises to help you practice what you've learned. To use the book, you just need to be familiar with the material in Learning Perl and have ambition to go further.Perl is a different language to different people. It is a quick scripting tool for some, and a fully-featured object-oriented language for others. It is used for everything from performing quick global replacements on text files, to crunching huge, complex sets of scientific data that take weeks to process. Perl is what you make of it. But regardless of what you use Perl for, this book helps you do it more effectively, efficiently, and elegantly.Learning Perl Objects, References & Modules is about learning to use Perl as a programming language, and not just a scripting language. This is the book that separates the Perl dabbler from the Perl programmer.

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