Perl Best Practices

Table of Contents

Dedication; Preface; Contents of This Book; Conventions Used in This Book; Code Examples; Feedback; Acknowledgments; Chapter 1: Best Practices; 1.1 Three Goals; 1.2 This Book; 1.3 Rehabiting; Chapter 2: Code Layout; 2.1 Bracketing; 2.2 Keywords; 2.3 Subroutines and Variables; 2.4 Builtins; 2.5 Keys and Indices; 2.6 Operators; 2.7 Semicolons; 2.8 Commas; 2.9 Line Lengths; 2.10 Indentation; 2.11 Tabs; 2.12 Blocks; 2.13 Chunking; 2.14 Elses; 2.15 Vertical Alignment; 2.16 Breaking Long Lines; 2.17 Non-Terminal Expressions; 2.18 Breaking by Precedence; 2.19 Assignments; 2.20 Ternaries; 2.21 Lists; 2.22 Automated Layout; Chapter 3: Naming Conventions; 3.1 Identifiers; 3.2 Booleans; 3.3 Reference Variables; 3.4 Arrays and Hashes; 3.5 Underscores; 3.6 Capitalization; 3.7 Abbreviations; 3.8 Ambiguous Abbreviations; 3.9 Ambiguous Names; 3.10 Utility Subroutines; Chapter 4: Values and Expressions; 4.1 String Delimiters; 4.2 Empty Strings; 4.3 Single-Character Strings; 4.4 Escaped Characters; 4.5 Constants; 4.6 Leading Zeros; 4.7 Long Numbers; 4.8 Multiline Strings; 4.9 Here Documents; 4.10 Heredoc Indentation; 4.11 Heredoc Terminators; 4.12 Heredoc Quoters; 4.13 Barewords; 4.14 Fat Commas; 4.15 Thin Commas; 4.16 Low-Precedence Operators; 4.17 Lists; 4.18 List Membership; Chapter 5: Variables; 5.1 Lexical Variables; 5.2 Package Variables; 5.3 Localization; 5.4 Initialization; 5.5 Punctuation Variables; 5.6 Localizing Punctuation Variables; 5.7 Match Variables; 5.8 Dollar-Underscore; 5.9 Array Indices; 5.10 Slicing; 5.11 Slice Layout; 5.12 Slice Factoring; Chapter 6: Control Structures; 6.1 If Blocks; 6.2 Postfix Selectors; 6.3 Other Postfix Modifiers; 6.4 Negative Control Statements; 6.5 C-Style Loops; 6.6 Unnecessary Subscripting; 6.7 Necessary Subscripting; 6.8 Iterator Variables; 6.9 Non-Lexical Loop Iterators; 6.10 List Generation; 6.11 List Selections; 6.12 List Transformation; 6.13 Complex Mappings; 6.14 List Processing Side Effects; 6.15 Multipart Selections; 6.16 Value Switches; 6.17 Tabular Ternaries; 6.18 do-while Loops; 6.19 Linear Coding; 6.20 Distributed Control; 6.21 Redoing; 6.22 Loop Labels; Chapter 7: Documentation; 7.1 Types of Documentation; 7.2 Boilerplates; 7.3 Extended Boilerplates; 7.4 Location; 7.5 Contiguity; 7.6 Position; 7.7 Technical Documentation; 7.8 Comments; 7.9 Algorithmic Documentation; 7.10 Elucidating Documentation; 7.11 Defensive Documentation; 7.12 Indicative Documentation; 7.13 Discursive Documentation; 7.14 Proofreading; Chapter 8: Built-in Functions; 8.1 Sorting; 8.2 Reversing Lists; 8.3 Reversing Scalars; 8.4 Fixed-Width Data; 8.5 Separated Data; 8.6 Variable-Width Data; 8.7 String Evaluations; 8.8 Automating Sorts; 8.9 Substrings; 8.10 Hash Values; 8.11 Globbing; 8.12 Sleeping; 8.13 Mapping and Grepping; 8.14 Utilities; Chapter 9: Subroutines; 9.1 Call Syntax; 9.2 Homonyms; 9.3 Argument Lists; 9.4 Named Arguments; 9.5 Missing Arguments; 9.6 Default Argument Values; 9.7 Scalar Return Values; 9.8 Contextual Return Values; 9.9 Multi-Contextual Return Values; 9.10 Prototypes; 9.11 Implicit Returns; 9.12 Returning Failure; Chapter 10: I/O; 10.1 Filehandles; 10.2 Indirect Filehandles; 10.3 Localizing Filehandles; 10.4 Opening Cleanly; 10.5 Error Checking; 10.6 Cleanup; 10.7 Input Loops; 10.8 Line-Based Input; 10.9 Simple Slurping; 10.10 Power Slurping; 10.11 Standard Input; 10.12 Printing to Filehandles; 10.13 Simple Prompting; 10.14 Interactivity; 10.15 Power Prompting; 10.16 Progress Indicators; 10.17 Automatic Progress Indicators; 10.18 Autoflushing; Chapter 11: References; 11.1 Dereferencing; 11.2 Braced References; 11.3 Symbolic References; 11.4 Cyclic References; Chapter 12: Regular Expressions; 12.1 Extended Formatting; 12.2 Line Boundaries; 12.3 String Boundaries; 12.4 End of String; 12.5 Matching Anything; 12.6 Lazy Flags; 12.7 Brace Delimiters; 12.8 Other Delimiters; 12.9 Metacharacters; 12.10 Named Characters; 12.11 Properties; 12.12 Whitespace; 12.13 Unconstrained Repetitions; 12.14 Capturing Parentheses; 12.15 Captured Values; 12.16 Capture Variables; 12.17 Piecewise Matching; 12.18 Tabular Regexes; 12.19 Constructing Regexes; 12.20 Canned Regexes; 12.21 Alternations; 12.22 Factoring Alternations; 12.23 Backtracking; 12.24 String Comparisons; Chapter 13: Error Handling; 13.1 Exceptions; 13.2 Builtin Failures; 13.3 Contextual Failure; 13.4 Systemic Failure; 13.5 Recoverable Failure; 13.6 Reporting Failure; 13.7 Error Messages; 13.8 Documenting Errors; 13.9 OO Exceptions; 13.10 Volatile Error Messages; 13.11 Exception Hierarchies; 13.12 Processing Exceptions; 13.13 Exception Classes; 13.14 Unpaccccccking Exceptions; Chapter 14: Command-Line Processing; 14.1 Command-Line Structure; 14.2 Command-Line Conventions; 14.3 Meta-options; 14.4 In-situ Arguments; 14.5 Command-Line Processing; 14.6 Interface Consistency; 14.7 Interapplication Consistency; Chapter 15: Objects; 15.1 Using OO; 15.2 Criteria; 15.3 Pseudohashes; 15.4 Restricted Hashes; 15.5 Encapsulation; 15.6 Constructors; 15.7 Cloning; 15.8 Destructors; 15.9 Methods; 15.10 Accessors; 15.11 Lvalue Accessors; 15.12 Indirect Objects; 15.13 Class Interfaces; 15.14 Operator Overloading; 15.15 Coercions; Chapter 16: Class Hierarchies; 16.1 Inheritance; 16.2 Objects; 16.3 Blessing Objects; 16.4 Constructor Arguments; 16.5 Base Class Initialization; 16.6 Construction and Destruction; 16.7 Automating Class Hierarchies; 16.8 Attribute Demolition; 16.9 Attribute Building; 16.10 Coercions; 16.11 Cumulative Methods; 16.12 Autoloading; Chapter 17: Modules; 17.1 Interfaces; 17.2 Refactoring; 17.3 Version Numbers; 17.4 Version Requirements; 17.5 Exporting; 17.6 Declarative Exporting; 17.7 Interface Variables; 17.8 Creating Modules; 17.9 The Standard Library; 17.10 CPAN; Chapter 18: Testing and Debugging; 18.1 Test Cases; 18.2 Modular Testing; 18.3 Test Suites; 18.4 Failure; 18.5 What to Test; 18.6 Debugging and Testing; 18.7 Strictures; 18.8 Warnings; 18.9 Correctness; 18.10 Overriding Strictures; 18.11 The Debugger; 18.12 Manual Debugging; 18.13 Semi-Automatic Debugging; Chapter 19: Miscellanea; 19.1 Revision Control; 19.2 Other Languages; 19.3 Configuration Files; 19.4 Formats; 19.5 Ties; 19.6 Cleverness; 19.7 Encapsulated Cleverness; 19.8 Benchmarking; 19.9 Memory; 19.10 Caching; 19.11 Memoization; 19.12 Caching for Optimization; 19.13 Profiling; 19.14 Enbugging; Essential Perl Best Practices; Perl Best Practices; , Code Layout; , Naming Conventions; , Values and Expressions; , Variables; , Control Structures; , Documentation; , Built-in Functions; , Subroutines; , I/O; , References; , Regular Expressions; , Error Handling; , Command-Line Processing; , Objects; , Class Hierarchies; , Modules; , Testing and Debugging; , Miscellanea; Editor Configurations; vim; vile; Emacs; BBEdit; TextWrangler; Recommended Modules and Utilities; Recommended Core Modules; Recommended CPAN Modules; Utility Subroutines; Bibliography; Perl Coding and Development Practices; General Coding and Development Practices; Colophon;

Damian Conway holds a PhD in Computer Science and is an honorary Associate Professor with the School of Computer Science and Software Engineering at Monash University, Melbourne, Australia.

Currently he runs an international IT training company—Thoughtstream—which provides programmer development from beginner to masterclass level throughout Europe, North America, and Australasia.

Damian was the winner of the 1998, 1999, and 2000 Larry Wall Awards for Practical Utility. The best technical paper at the annual Perl Conference was subsequently named in his honour. He is a member of the technical committee for The Perl Conference, a keynote speaker at many Open Source conferences, a former columnist for The Perl Journal, and author of the book Object Oriented Perl. In 2001 Damian received the first "Perl Foundation Development Grant" and spent 20 months working on projects for the betterment of Perl.

A popular speaker and trainer, he is also the author of numerous well-known Perl modules, including Parse::RecDescent (a sophisticated parsing tool), Class::Contract (design-by-contract programming in Perl), Lingua::EN::Inflect (rule-based English transformations for text generation), Class::Multimethods (multiple dispatch polymorphism), Text::Autoformat (intelligent automatic reformatting of plaintext), Switch (Perl's missing case statement), NEXT (resumptive method dispatch), Filter::Simple (Perl-based source code manipulation), Quantum::Superpositions (auto-parallelization of serial code using a quantum mechanical metaphor), and Lingua::Romana::Perligata (programming in Latin).

Most of his time is now spent working with Larry Wall on the design of the new Perl 6 programming language.