Beginning Perl

INTRODUCTION xxiii CHAPTER 1: WHAT IS PERL? 1 Perl Today 2 Getting Perl 3 Working with Non-Windows Platforms: perlbrew 4 Using Windows 6 The Perl Community 8 IRC 8 PerlMonks 9 Perl Mongers 9 StackOverflow 9 Using perldoc 11 Understanding the Structure of perldoc 11 Getting Started with perldoc 11 Using Tutorials and FAQs 12 Using the perldoc -f function 14 Using a Terminal Window 14 Using the Command Line 15 Creating a Work Directory 16 Creating Hello, World! 18 Writing Your First Program 18 Shebang Lines 21 Summary 22 CHAPTER 2: UNDERSTANDING THE CPAN 25 CPAN and METACPAN 26 Finding and Evaluating Modules 27 Downloading and Installing 29 CPAN Clients 33 Using the CPAN.pm Client 33 Using the Cpanm Client 35 PPM 36 CPAN::Mini 36 Summary 39 CHAPTER 3: VARIABLES 41 What Is Programming? 42 A Few Things to Note Before Getting Started 43 strict, warnings, and diagnostics 43 The my Function 43 Sigils 44 Identifiers 45 Scalars 46 Strings 47 Numbers 51 Arrays 53 Breaking Down the Code 54 Accessing Elements 55 Iterating over Arrays 58 Hashes 58 Accessing Elements 59 Iterating Over Hashes 60 Adding Data to Hashes 60 Slices 61 Array Slices 62 Hash Slices 62 Context 63 Scalar Context 63 List Context 64 Scope 67 my Variables 67 Package Variables 69 Strict, Warnings, and Diagnostics 72 strict 74 warnings 74 diagnostics 75 Working Without a Net 76 Perl's Built-in Variables 78 $_ 78 %ENV 79 @ARGV 79 Other Special Variables 80 Summary 81 CHAPTER 4: WORKING WITH DATA 83 Using Scalars 84 Working with Strings 85 Using String Operators 94 Scalar::Util 97 Numeric Builtins 98 Bitwise Operators 103 Understanding Booleans 103 Assignment Operators 108 Precedence and Associativity 109 Array and List Functions 111 Built-in Array Functions 111 List::Util 116 Built-in Hash Functions 116 delete() 116 exists() 117 keys() 117 values() 117 each() 117 Scoping Keywords 119 my() 119 local() 119 our() 120 state() 120 Summary 121 CHAPTER 5: CONTROL FLOW 125 Using the if Statement 126 Understanding Basic Conditionals 126 else/elsif/unless 128 The Ternary Operator ?: 131 for/foreach loops 132 Arrays 132 Lists 135 C-Style 136 Using while/until Loops 142 Lists 143 last/next/redo/continue 144 Labels 146 Statement Modifiers 147 Types of Statement Modifiers 147 do while/do until 149 given/when 151 Basic Syntax 151 The Switch Module 153 Summary 154 CHAPTER 6: REFERENCES 157 References 101 158 Array References 158 Hash References 159 Anonymous References 160 Other References 163 Working with References 166 Debugging 166 Copying 169 Slices 172 Summary 173 CHAPTER 7: SUBROUTINES 175 Subroutine Syntax 176 Argument Handling 177 Multiple Arguments 178 Named Arguments 179 Aliasing 181 State Variables (Pre- and Post-5.10) 181 Passing a List, Hash, or Hashref? 184 Returning Data 186 Returning True/False 186 Returning Single and Multiple Values 188 wantarray 189 FAIL! 190 "Wake Up! Time to Die!" 191 carp and croak 192 eval 192 evalGotchas 194 Try::Tiny 195 Subroutine References 196 Existing Subroutines 196 Anonymous Subroutines 197 Closures 197 Prototypes 200 Argument Coercion 200 More Prototype Tricks 202 Mimicking Builtins 204 Forward Declarations 206 Prototype Summary 207 Recursion 209 Basic Recursion 209 Divide and Conquer 210 Memoization 211 Things to Watch For 215 Argument Aliasing 215 Scope Issues 216 Doing Too Much 216 Too Many Arguments 217 Summary 217 CHAPTER 8: REGULAR EXPRESSIONS 219 Basic Matching 220 Quantifiers 221 Escape Sequences 223 Extracting Data 226 Modifiers and Anchors 228 Character Classes 231 Grouping 232 Advanced Matching 235 Substitutions 235 Lookahead/Lookbehind Anchors 236 Named Subexpressions (5.10) 238 Common Regular Expression Issues 241 Regexp::Common 241 E-mail Addresses 242 HTML 242 Composing Regular Expressions 243 Summary 245 CHAPTER 9: FILES AND DIRECTORIES 249 Basic File Handling 250 Opening and Reading a File 250 File Test Operators 258 The Diamond Operator 260 Temporary Files 260 DATA as a File 261 binmode 262 Directories 265 Reading Directories 265 Globbing 265 Unicode 266 What Is Unicode? 267 Two Simple Rules 267 Lots of Complicated Rules 271 Useful Modules 276 File::Find 276 File::Path 278 File::Find::Rule 279 Summary 284 CHAPTER 10: SORT, MAP, AND GREP 287 Basic Sorting 288 Sorting Alphabetically 288 Sorting Numerically 289 Reverse Sorting 290 Complex Sort Conditions 290 Writing a sort Subroutine 292 Sorting and Unicode Fun! 293 map and grep 297 Using grep 298 Using map 303 Aliasing Issues 305 Trying to Do Too Much 306 Trying to Be Clever 307 Putting It All Together 308 Schwartzian Transform (aka decorate, sort, undecorate) 308 Guttman-Rosler Transform 310 Summary 311 CHAPTER 11: PACKAGES AND MODULES 315 Namespaces and Packages 316 use Versus require 321 Package Variables 323 Version Numbers 326 Subroutines in Other Packages 327 Exporting 327 Naming Conventions 330 BEGIN, UNITCHECK, CHECK, INIT, and END 335 BEGIN blocks 336 END Blocks 337 INIT, CHECK, and UNITCHECK Blocks 337 Plain Old Documentation (POD) 338 Documentation Structure 340 Headings 340 Paragraphs 341 Lists 341 Verbatim 342 Miscellaneous 342 Creating and Installing Modules 344 Creating a Simple Module 344 Makefile.PL or Module::Build? 349 Summary 349 CHAPTER 12: OBJECT ORIENTED PERL 353 What Are Objects? The Ævar the Personal Shopper 354 Three Rules of Perl OO 355 Class Is a Package 355 An Object Is a Reference That Knows Its Class 356 A Method Is a Subroutine 358 Objects - Another View 371 Using TV::Episode 371 Subclassing 374 Using TV::Episode::Broadcast 375 Class Versus Instance Data 379 A Brief Recap 381 Overloading Objects 381 Using UNIVERSAL 385 Understanding Private Methods 387 Gotchas 393 Unnecessary Methods 393 "Reaching Inside" 394 Multiple Inheritance 394 Summary 397 CHAPTER 13: MOOSE 399 Understanding Basic Moose Syntax 400 Using Attributes 402 Using Constructors 405 Understanding Inheritance 408 Taking Care of Your Moose 409 Advanced Moose Syntax 413 Using Type Constraints 414 Using Method Modifiers 417 Understanding and Using Roles 420 Exploring MooseX 425 Rewriting Television::Episode 428 Moose Best Practices 433 Use namespace::autoclean and Make Your Class Immutable 434 Never Override new() 434 Always Call Your Parent BUILDARGS Method 434 Provide Defaults if an Attribute is Not Required 434 Default to Read-Only 434 Put Your Custom Types in One Module and Give Them a Namespace 435 Don't Use Multiple Inheritance 435 Always Consume All Your Roles at Once 435 Summary 436 CHAPTER 14: TESTING 439 Basic Tests 440 Using Test::More 440 Writing Your Tests 442 Understanding the prove Utility 443 Understanding Test::More Test Functions 444 Using ok 445 Using is 445 Using like 448 Using is_deeply 449 Using SKIP 450 Using TODO 450 Using eval {} 451 Using use_ok and require_ok 452 Working with Miscellaneous Test Functions 453 Using Other Testing Modules 457 Using Test::Diff erences 457 Using Test::Exception 459 Using Test::Warn 460 Using Test::Most 460 Understanding xUnit Style Using Testing 461 Using Test::Class 461 A Basic Test Class 463 Extending a Test Class 467 Using Test Control Methods 471 Calling Parent Test Control Methods 473 Summary 477 CHAPTER 15: THE INTERWEBS 481 A Brief Introduction to HTTP 482 Plack 484 Hello, World! 484 Handling Parameters 490 Templates 492 Handling POST Requests 496 Sessions 500 Web Clients 511 Extracting Links from Web Pages 512 Extracting Comments from Web Pages 514 Filling Out Forms Programmatically 515 Summary 520 CHAPTER 16: DATABASES 523 Using the DBI 524 Connecting to a Database 524 Using SQLite 527 Using DBD::SQLite 527 Selecting Basic Data 533 Using SELECT Statements 533 Using Bind Parameters 536 Inserting and Updating Data 539 Creating Transactions 540 Handling Errors 541 Summary 542 CHAPTER 17: PLAYS WELL WITH OTHERS 545 The Command Line 546 Reading User Input 546 Handling Command-Line Arguments 548 perlrun 551 Other Programs 556 Running an External Program 556 Reading Another Program's Output 559 Writing to Another Program's Input 560 STDERR 562 Summary 565 CHAPTER 18: COMMON TASKS 567 Using CSV Data 568 Reading CSV Data 569 Writing CSV Data 570 Understanding Basic XML 571 Reading CSV Data 572 Writing CSV Data 576 Handling Dates 580 Using the DateTime Module 580 Using Date::Tiny and DateTime::Tiny 581 Understanding Your Program 587 Using the Debugger 587 Profiling 594 Perl::Critic 604 Summary 608 CHAPTER 19: THE NEXT STEPS 611 What Next? 612 What This Book Covers 612 What This Book Leaves Out 613 Understanding Object-Relational Mappers 613 Understanding DBIx::Class 614 Understanding Basic DBIx::Class Usage 614 Understanding the Pros and Cons of an ORM 618 Using DBIx::Class::Schema::Loader 624 Using the Template Toolkit 625 Why Use Templates? 625 An Introduction to Template Toolkit 626 Using Catalyst to Build Apps 634 The Beauty of MVC 635 Setting Up a Catalyst Application 635 Using Catalyst Views 641 Using Catalyst Models 643 Using Catalyst Controllers 646 CRUD: Create, Read, Update, and Delete 648 Summary 651 APPENDIX: ANSWERS TO EXERCISES 655 INDEX 695