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.

Read now

Unlock full access

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

Content preview from Learning Perl Objects, References, and Modules

Chapter 13. Writing a Distribution

In Chapter 12, you created a fictional Island::Plotting::Maps module, and built the right support for Exporter so that you could include use Island::Plotting::Maps in a program.

While the resulting .pm file is useful, it’s not very practical. There’s a lot more to building a real module than just creating the .pm file. You’ll also need to consider and implement the following questions:

Installation location: How and where is the .pm file installed so a program can find the module in its @INC path?
Documentation: Where is the documentation for the module? How is the documentation installed so the user can read it?
Archive completeness: If there are any accompanying files, where are they? How can the end user know if any missing files are missing?
Testing: What test harnesses can the developer run to verify correct operation, including testing against older known bugs? Can these same tests be run by the installer to ensure proper operation in the target environment?
C-language interfaces: If the module contains C or C++ code (not covered here), how can the developer describe how to compile and link the code in the developer’s environment, or the end user environment?

As Roy Scheider uttered in the movie Jaws: “You’re gonna need a bigger boat.” That “bigger boat” is the difference between a module and a distribution.

Starting with h2xs

A distribution contains the module (or collection of related modules), plus all the support files required to document, test, ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.

Read now

Unlock full access

More than 5,000 organizations count on O’Reilly

O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.

Julian F.

Head of Cybersecurity

I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.

Addison B.

Field Engineer

I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.

Amir M.

Data Platform Tech Lead

I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.

Mark W.

Embedded Software Engineer

Publisher Resources

ISBN: 0596004788Errata Page

Cloud Computing

Data Engineering

Data Science

AI & ML

Programming Languages

Software Architecture

IT/Ops

Security

Design

Business

Soft Skills

Learning Perl Objects, References, and Modules

by Randal L. Schwartz, Tom Phoenix

Chapter 13. Writing a Distribution

Starting with h2xs

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.