Object Oriented Perl: A Comprehensive Guide to Concepts and Programming Techniques

Conway's Object Oriented Perl provides an invaluable guide to virtually every aspect of object-oriented programming in Perl.The most notable thing about Object Oriented Perl is Conway's excellent perspective on object-oriented concepts and how they are implemented in Perl. This book does a remarkable job of cutting through traditional jargon and illustrating how basic object-oriented design techniques are handled in Perl. (A useful appendix attests to the author's wide-ranging knowledge, with a comparison of Smalltalk, Eiffel, C++, and Java with Perl, including a summary of object-oriented syntax for each.) This book also features a truly excellent review of basic Perl syntax.Throughout this text, the author shows you the basics of solid object design (illustrated using classes that model music CDs). Basic concepts like inheritance and polymorphism get thorough and clear coverage. The book also points out common mistakes and provides many tips for navigating the powerful and flexible (yet sometimes tricky) nuances of using Perl objects. For instance, Conway shows how to achieve true data encapsulation in Perl (which generally allows calls across modules) as well as its natural support for generic programming techniques.He also pays special attention to popular object modules available from CPAN (like Class::MethodmakerK, which simplifies declaring classes) and discusses performance issues and the tradeoff between programming convenience and speed often faced by today's Perl developer. Advanced chapters cover a number of techniques for adding persistence and invoking methods using multiple dispatching.Filled with syntactic tips and tricks, Object Oriented Perl is a sure bet for any programmer who wants to learn how to use Perl objects effectively contents 7 foreword 11 preface 12 acknowledgments 18 author online 20 What you need to know first (An object orientation primer) 21 1.1 The essentials of object orientation 22 1.1.1 Objects 22 1.1.2 Classes 23 1.1.3 Class attributes and methods 24 1.1.4 Inheritance 25 1.1.5 Polymorphism 29 1.2 Other object-oriented concepts 33 1.2.1 Interface vs. implementation 33 1.2.2 Aggregation 34 1.2.3 Genericity 35 1.2.4 Persistence 36 1.3 Terminology: a few (too many) words 38 1.4 Where to find out more 38 1.4.1 Books 39 1.4.2 Websites 39 1.4.3 Newsgroups 40 1.5 Summary 40 What you need to know second (A Perl refresher) 41 2.1 Essential Perl 41 2.1.1 Scalars 41 2.1.2 Arrays 42 2.1.3 Hashes 46 2.1.4 Subroutines 48 2.1.5 References and referents 57 2.1.6 Packages 63 2.2 Nonessential (but very useful) Perl 71 2.2.1 Modules 71 2.2.2 Autoloading 75 2.2.3 Closures 76 2.2.4 Typeglobs 79 2.3 The CPAN 85 2.3.1 How to access the CPAN 86 2.3.2 How to search the CPAN 86 2.3.3 How to install modules from the CPAN 87 2.4 Where to find out more 88 2.4.1 Essential books 89 2.4.2 Useful books 89 2.4.3 The Perl documentation 90 2.4.4 The Perl Journal 90 2.4.5 Websites 91 2.4.6 Newsgroups 91 2.5 Summary 92 Getting Started 93 3.1 Three little rules 93 3.1.1 Rule 1: To create a class, build a package 94 3.1.2 Rule 2: To create a method, write a subroutine 94 3.1.3 Rule 3: To create an object, bless a referent 96 3.2 A simple Perl class 100 3.2.1 The code 100 3.2.2 Using the CD::Music class 108 3.3 Making life easier 109 3.3.1 Class modules 109 3.3.2 use strict and the -w flag 109 3.3.3 Automating data member access 111 3.3.4 Documenting a class 114 3.4 The creation and destruction of objects 116 3.4.1 Constructors 116 3.4.2 Destructors 126 3.5 The CD::Music class, compleat 134 3.6 Summary 137 Blessing arrays and scalars 138 4.1 What’s wrong with a hash? 138 4.2 Blessing an array 139 4.2.1 An array-specific example—iterators 143 4.2.2 Where to find out more 146 4.3 Blessing a pseudo-hash 146 4.3.1 A pseudo what??? 146 4.3.2 Advantages of a pseudo-hash 148 4.3.3 The worst of both worlds? 149 4.3.4 Compile-time support for run-time performance 150 4.3.5 Typed lexicals 151 4.3.6 Yet another version of CD::Music 152 4.3.7 Where to find out more 155 4.4 Blessing a scalar 155 4.4.1 Why not bless a scalar? 155 4.4.2 An object-oriented password 156 4.4.3 A bit-string class 158 4.4.4 Where to find out more 161 4.5 Summary 162 Blessing other things 163 5.1 Blessing a regular expression 163 5.1.1 The qr operator 163 5.1.2 Why an object-oriented regular expression class? 165 5.1.3 Designing a different regular expressions mechanism 166 5.1.4 A closer look at the two classes 168 5.1.5 On the separation of Search and State 171 5.1.6 Where to find out more 171 5.2 Blessing a subroutine 171 5.2.1 So, how can a subroutine be an object? 171 5.2.2 Why objectify a subroutine? 173 5.2.3 A lexer object 174 5.2.4 Example: A simple pretty-printer 177 5.2.5 Where to find out more 177 5.3 Blessing a typeglob 178 5.3.1 Paging STDOUT 179 5.3.2 A multiprocess pager class 180 5.3.3 A threaded pager class 184 5.3.4 Where to find out more 186 5.4 Summary 186 Inheritance 188 6.1 How Perl handles inheritance 188 6.1.1 The @ISA array 188 6.1.2 What inheritance means in Perl 189 6.1.3 Where the call goes 191 6.1.4 Constructors and inheritance 191 6.1.5 Diamonds are forfended 195 6.1.6 Destructors and inheritance 196 6.2 Tricks and traps 198 6.2.1 The isa() method 198 6.2.2 The can() method 199 6.2.3 The UNIVERSAL package 202 6.2.4 The SUPER pseudo-package 203 6.2.5 Implementing abstract methods 205 6.2.6 Naming attributes of derived classes 206 6.2.7 The empty subclass test 209 6.2.8 Inheritance and pseudo-hashes 210 6.3 Example: Inheriting the CD class 213 6.3.1 Applied Laziness 213 6.3.2 Class data access revisited 216 6.3.3 An alternative solution 218 6.4 Where to find out more 221 6.5 Summary 222 Polymorphism 223 7.1 Polymorphism in Perl 223 7.1.1 Interface polymorphism 224 7.1.2 Inheritance polymorphism 224 7.2 Example: Polymorphic methods for the Lexer class 225 7.3 The simple pretty-printer objectified 228 7.4 Using interface polymorphism instead 230 7.5 Where to find out more 232 7.6 Summary 232 Automating class creation 233 8.1 The Class::Struct module 233 8.1.1 Creating classes 233 8.1.2 Attribute types 235 8.1.3 Hierarchical class structures 238 8.1.4 Initializing objects 239 8.1.5 Inheritance and generated classes 239 8.1.6 A full example—automating the CD::Music class 240 8.2 The Class::MethodMaker module 242 8.2.1 Constructors 243 8.2.2 Scalar attributes 244 8.2.3 Grouped scalar attributes 245 8.2.4 Flaglike attributes 246 8.2.5 Keylike attributes 246 8.2.6 Nonscalar attributes 247 8.2.7 Class attributes 248 8.2.8 Nested objects as attributes 248 8.2.9 Subroutines as attributes 251 8.2.10 Abstract methods 252 8.2.11 Inheritance and generated classes 253 8.2.12 A full example: reautomating the CD::Music class 253 8.3 Where to find out more 254 8.4 Summary 255 Ties 256 9.1 A jacketing tie required 256 9.1.1 Limitations of tie-ing 257 9.2 Tie-ing a scalar 258 9.2.1 Untie-ing a scalar 258 9.2.2 A simple example 259 9.2.3 Implementing a scalar using a nonscalar 261 9.3 Tie-ing a hash 263 9.3.1 Example: case-insensitive hashes 265 9.4 Tie-ing an array 269 9.4.1 Example: a base/codon array 270 9.5 Tie-ing a filehandle 276 9.5.1 An example: filtered filehandles 277 9.6 Inheriting from a tie-able package 282 9.6.1 Example: sorted hashes 282 9.6.2 Another example: micro-tracked scalars 284 9.7 Tied variables as objects 285 9.7.1 A DNA class 285 9.7.2 Object-oriented tied filehandles 288 9.7.3 Blessing and tie-ing to the same package 290 9.8 Where to find out more 294 9.9 Summary 295 Operator overloading 296 10.1 The problem 296 10.2 Perl’s operator overloading mechanism 298 10.2.1 “Automagic” operators 300 10.2.2 Fallback operations 301 10.2.3 Specifying conversion operations 302 10.3 Example: A Roman numerals class 304 10.3.1 Creating class constants 308 10.4 Circumventing undesired reference semantics 311 10.5 The use and abuse of operators 312 10.5.1 When to overload? 314 10.6 Where to find out more 315 10.7 Summary 315 Encapsulation 316 11.1 The perils of trust 316 11.2 Encapsulation via closures 317 11.2.1 A variation for the paranoid 320 11.3 Encapsulation via scalars 322 11.3.1 Name, rank, and serial number 322 11.3.2 Controlled access 324 11.3.3 Roll call 326 11.3.4 A question of identity 326 11.3.5 A variation for the truly paranoid 327 11.4 Encapsulation via ties 329 11.4.1 A limited-access hash 331 11.4.2 Constructing a securehash 331 11.4.3 Declaring securehash entries 332 11.4.4 Accessing securehash entries 333 11.4.5 Iterating a securehash 335 11.4.6 Ambiguous keys in a securehash 336 11.4.7 Debugging a securehash 339 11.4.8 "Fast" securehashes 341 11.4.9 “Strict” securehashes 343 11.4.10 The formal access rules 344 11.5 Where to find out more 346 11.6 Summary 346 Genericity 347 12.1 Why Perl doesn’t need special generic mechanisms 347 12.2 Using specific mechanisms anyway 349 12.2.1 Closures as generic methods 349 12.2.2 Eval-ing generic classes 354 12.3 Implicit generics via polymorphism 356 12.3.1 The generic Tree class 356 12.3.2 A specific node class 359 12.3.3 Building related node classes 362 12.3.4 Cleaning up the act: an abstract base class 363 12.3.5 An unrelated node class 364 12.3.6 Putting it all together 368 12.3.7 A philosophical note 369 12.4 Where to find out more 370 12.5 Summary 370 Multiple dispatch 371 13.1 What is multiple dispatch? 371 13.2 Multiple dispatch via single dispatch and cases 373 13.3 Multiple dispatch via a table 376 13.3.1 Determining the table initialization order 379 13.3.2 Ordering problems 380 13.4 Comparing the two approaches 381 13.5 Dynamic dispatch tables 383 13.5.1 No free lunch... 386 13.6 Some lingering difficulties 387 13.7 The Class::Multimethods module 387 13.7.1 Identifying the nearest multimethod 388 13.7.2 Finding the nearest multimethod 389 13.7.3 Implications of breadth-first multimethod dispatch 392 13.7.4 Handling resolution failure 396 13.7.5 Defining multimethods outside their classes 398 13.7.6 Multimethods as regular subroutines 400 13.7.7 Nonclass types as parameters 401 13.7.8 Last resort parameters 402 13.7.9 Recursive multiple dispatch 403 13.7.10 Debugging a multimethod 404 13.8 Comparing the three approaches 405 13.9 Where to find out more 405 13.10 Summary 405 Persistent objects 407 14.1 The ingredients 407 14.1.1 Identity 408 14.1.2 Encoding/serialization 409 14.1.3 Storage 412 14.1.4 Coordination 417 14.2 Object-oriented persistence 418 14.2.1 Encoding objects 418 14.2.2 Object-oriented encoding 419 14.3 Coarse-grained persistence 420 14.3.1 Class-specific persistence 420 14.3.2 Some improvements 424 14.3.3 Coarse-grained persistence for any data 428 14.3.4 Assessing the technique 432 14.4 Fine-grained persistence 432 14.4.1 Disk files as objects 433 14.4.2 Memory-mapped files as objects 436 14.4.3 Tied databases as objects 438 14.4.4 Fine-grained persistence for any class 441 14.4.5 Easier persistence through genericity 444 14.4.6 Assessing the technique 447 14.5 Where to find out more 447 14.6 Summary 448 Quick reference guide 449 What you might know instead 458 B.1 Perl and Smalltalk 458 B.1.1 Objects 459 B.1.2 Classes 459 B.1.3 Methods 459 B.1.4 Encapsulation 460 B.1.5 Inheritance 461 B.1.6 Polymorphism 461 B.1.7 Control structures and exception handling 462 B.1.8 Comparative syntax 462 B.1.9 Where to find out more 463 B.2 Perl and C++ 463 B.2.1 Objects 464 B.2.2 Classes 464 B.2.3 Methods 465 B.2.4 Constructors and destructors 466 B.2.5 Encapsulation 466 B.2.6 Inheritance 466 B.2.7 Polymorphism 466 B.2.8 Comparative syntax 467 B.2.9 Where to find out more 469 B.3 Perl and Java 469 B.3.1 Objects 469 B.3.2 Classes 470 B.3.3 Methods 470 B.3.4 Constructors and finalizers 471 B.3.5 Encapsulation 471 B.3.6 Inheritance 471 B.3.7 Polymorphism 471 B.3.8 Exception handling 472 B.3.9 Comparative syntax 472 B.3.10 Where to find out more 474 B.4 Perl and Eiffel 474 B.4.1 Objects 474 B.4.2 Classes 474 B.4.3 Methods 475 B.4.4 Encapsulation 476 B.4.5 Inheritance 476 B.4.6 Polymorphism 476 B.4.7 Genericity 477 B.4.8 Comparative syntax 477 B.4.9 Where to find out more 477 glossary 479 bibliography 486 index 488 contents......Page 7 foreword......Page 11 preface......Page 12 acknowledgments......Page 18 author online......Page 20 What you need to know first (An object orientation primer)......Page 21 1.1.1 Objects......Page 22 1.1.2 Classes......Page 23 1.1.3 Class attributes and methods......Page 24 1.1.4 Inheritance......Page 25 1.1.5 Polymorphism......Page 29 1.2.1 Interface vs. implementation......Page 33 1.2.2 Aggregation......Page 34 1.2.3 Genericity......Page 35 1.2.4 Persistence......Page 36 1.4 Where to find out more......Page 38 1.4.2 Websites......Page 39 1.5 Summary......Page 40 2.1.1 Scalars......Page 41 2.1.2 Arrays......Page 42 2.1.3 Hashes......Page 46 2.1.4 Subroutines......Page 48 2.1.5 References and referents......Page 57 2.1.6 Packages......Page 63 2.2.1 Modules......Page 71 2.2.2 Autoloading......Page 75 2.2.3 Closures......Page 76 2.2.4 Typeglobs......Page 79 2.3 The CPAN......Page 85 2.3.2 How to search the CPAN......Page 86 2.3.3 How to install modules from the CPAN......Page 87 2.4 Where to find out more......Page 88 2.4.2 Useful books......Page 89 2.4.4 The Perl Journal......Page 90 2.4.6 Newsgroups......Page 91 2.5 Summary......Page 92 3.1 Three little rules......Page 93 3.1.2 Rule 2: To create a method, write a subroutine......Page 94 3.1.3 Rule 3: To create an object, bless a referent......Page 96 3.2.1 The code......Page 100 3.2.2 Using the CD::Music class......Page 108 3.3.2 use strict and the -w flag......Page 109 3.3.3 Automating data member access......Page 111 3.3.4 Documenting a class......Page 114 3.4.1 Constructors......Page 116 3.4.2 Destructors......Page 126 3.5 The CD::Music class, compleat......Page 134 3.6 Summary......Page 137 4.1 What’s wrong with a hash?......Page 138 4.2 Blessing an array......Page 139 4.2.1 An array-specific example—iterators......Page 143 4.3.1 A pseudo what???......Page 146 4.3.2 Advantages of a pseudo-hash......Page 148 4.3.3 The worst of both worlds?......Page 149 4.3.4 Compile-time support for run-time performance......Page 150 4.3.5 Typed lexicals......Page 151 4.3.6 Yet another version of CD::Music......Page 152 4.4.1 Why not bless a scalar?......Page 155 4.4.2 An object-oriented password......Page 156 4.4.3 A bit-string class......Page 158 4.4.4 Where to find out more......Page 161 4.5 Summary......Page 162 5.1.1 The qr operator......Page 163 5.1.2 Why an object-oriented regular expression class?......Page 165 5.1.3 Designing a different regular expressions mechanism......Page 166 5.1.4 A closer look at the two classes......Page 168 5.2.1 So, how can a subroutine be an object?......Page 171 5.2.2 Why objectify a subroutine?......Page 173 5.2.3 A lexer object......Page 174 5.2.5 Where to find out more......Page 177 5.3 Blessing a typeglob......Page 178 5.3.1 Paging STDOUT......Page 179 5.3.2 A multiprocess pager class......Page 180 5.3.3 A threaded pager class......Page 184 5.4 Summary......Page 186 6.1.1 The @ISA array......Page 188 6.1.2 What inheritance means in Perl......Page 189 6.1.4 Constructors and inheritance......Page 191 6.1.5 Diamonds are forfended......Page 195 6.1.6 Destructors and inheritance......Page 196 6.2.1 The isa() method......Page 198 6.2.2 The can() method......Page 199 6.2.3 The UNIVERSAL package......Page 202 6.2.4 The SUPER pseudo-package......Page 203 6.2.5 Implementing abstract methods......Page 205 6.2.6 Naming attributes of derived classes......Page 206 6.2.7 The empty subclass test......Page 209 6.2.8 Inheritance and pseudo-hashes......Page 210 6.3.1 Applied Laziness......Page 213 6.3.2 Class data access revisited......Page 216 6.3.3 An alternative solution......Page 218 6.4 Where to find out more......Page 221 6.5 Summary......Page 222 7.1 Polymorphism in Perl......Page 223 7.1.2 Inheritance polymorphism......Page 224 7.2 Example: Polymorphic methods for the Lexer class......Page 225 7.3 The simple pretty-printer objectified......Page 228 7.4 Using interface polymorphism instead......Page 230 7.6 Summary......Page 232 8.1.1 Creating classes......Page 233 8.1.2 Attribute types......Page 235 8.1.3 Hierarchical class structures......Page 238 8.1.5 Inheritance and generated classes......Page 239 8.1.6 A full example—automating the CD::Music class......Page 240 8.2 The Class::MethodMaker module......Page 242 8.2.1 Constructors......Page 243 8.2.2 Scalar attributes......Page 244 8.2.3 Grouped scalar attributes......Page 245 8.2.5 Keylike attributes......Page 246 8.2.6 Nonscalar attributes......Page 247 8.2.8 Nested objects as attributes......Page 248 8.2.9 Subroutines as attributes......Page 251 8.2.10 Abstract methods......Page 252 8.2.12 A full example: reautomating the CD::Music class......Page 253 8.3 Where to find out more......Page 254 8.4 Summary......Page 255 9.1 A jacketing tie required......Page 256 9.1.1 Limitations of tie-ing......Page 257 9.2.1 Untie-ing a scalar......Page 258 9.2.2 A simple example......Page 259 9.2.3 Implementing a scalar using a nonscalar......Page 261 9.3 Tie-ing a hash......Page 263 9.3.1 Example: case-insensitive hashes......Page 265 9.4 Tie-ing an array......Page 269 9.4.1 Example: a base/codon array......Page 270 9.5 Tie-ing a filehandle......Page 276 9.5.1 An example: filtered filehandles......Page 277 9.6.1 Example: sorted hashes......Page 282 9.6.2 Another example: micro-tracked scalars......Page 284 9.7.1 A DNA class......Page 285 9.7.2 Object-oriented tied filehandles......Page 288 9.7.3 Blessing and tie-ing to the same package......Page 290 9.8 Where to find out more......Page 294 9.9 Summary......Page 295 10.1 The problem......Page 296 10.2 Perl’s operator overloading mechanism......Page 298 10.2.1 “Automagic” operators......Page 300 10.2.2 Fallback operations......Page 301 10.2.3 Specifying conversion operations......Page 302 10.3 Example: A Roman numerals class......Page 304 10.3.1 Creating class constants......Page 308 10.4 Circumventing undesired reference semantics......Page 311 10.5 The use and abuse of operators......Page 312 10.5.1 When to overload?......Page 314 10.7 Summary......Page 315 11.1 The perils of trust......Page 316 11.2 Encapsulation via closures......Page 317 11.2.1 A variation for the paranoid......Page 320 11.3.1 Name, rank, and serial number......Page 322 11.3.2 Controlled access......Page 324 11.3.4 A question of identity......Page 326 11.3.5 A variation for the truly paranoid......Page 327 11.4 Encapsulation via ties......Page 329 11.4.2 Constructing a securehash......Page 331 11.4.3 Declaring securehash entries......Page 332 11.4.4 Accessing securehash entries......Page 333 11.4.5 Iterating a securehash......Page 335 11.4.6 Ambiguous keys in a securehash......Page 336 11.4.7 Debugging a securehash......Page 339 11.4.8 "Fast" securehashes......Page 341 11.4.9 “Strict” securehashes......Page 343 11.4.10 The formal access rules......Page 344 11.6 Summary......Page 346 12.1 Why Perl doesn’t need special generic mechanisms......Page 347 12.2.1 Closures as generic methods......Page 349 12.2.2 Eval-ing generic classes......Page 354 12.3.1 The generic Tree class......Page 356 12.3.2 A specific node class......Page 359 12.3.3 Building related node classes......Page 362 12.3.4 Cleaning up the act: an abstract base class......Page 363 12.3.5 An unrelated node class......Page 364 12.3.6 Putting it all together......Page 368 12.3.7 A philosophical note......Page 369 12.5 Summary......Page 370 13.1 What is multiple dispatch?......Page 371 13.2 Multiple dispatch via single dispatch and cases......Page 373 13.3 Multiple dispatch via a table......Page 376 13.3.1 Determining the table initialization order......Page 379 13.3.2 Ordering problems......Page 380 13.4 Comparing the two approaches......Page 381 13.5 Dynamic dispatch tables......Page 383 13.5.1 No free lunch.........Page 386 13.7 The Class::Multimethods module......Page 387 13.7.1 Identifying the nearest multimethod......Page 388 13.7.2 Finding the nearest multimethod......Page 389 13.7.3 Implications of breadth-first multimethod dispatch......Page 392 13.7.4 Handling resolution failure......Page 396 13.7.5 Defining multimethods outside their classes......Page 398 13.7.6 Multimethods as regular subroutines......Page 400 13.7.7 Nonclass types as parameters......Page 401 13.7.8 Last resort parameters......Page 402 13.7.9 Recursive multiple dispatch......Page 403 13.7.10 Debugging a multimethod......Page 404 13.10 Summary......Page 405 14.1 The ingredients......Page 407 14.1.1 Identity......Page 408 14.1.2 Encoding/serialization......Page 409 14.1.3 Storage......Page 412 14.1.4 Coordination......Page 417 14.2.1 Encoding objects......Page 418 14.2.2 Object-oriented encoding......Page 419 14.3.1 Class-specific persistence......Page 420 14.3.2 Some improvements......Page 424 14.3.3 Coarse-grained persistence for any data......Page 428 14.4 Fine-grained persistence......Page 432 14.4.1 Disk files as objects......Page 433 14.4.2 Memory-mapped files as objects......Page 436 14.4.3 Tied databases as objects......Page 438 14.4.4 Fine-grained persistence for any class......Page 441 14.4.5 Easier persistence through genericity......Page 444 14.5 Where to find out more......Page 447 14.6 Summary......Page 448 Quick reference guide......Page 449 B.1 Perl and Smalltalk......Page 458 B.1.3 Methods......Page 459 B.1.4 Encapsulation......Page 460 B.1.6 Polymorphism......Page 461 B.1.8 Comparative syntax......Page 462 B.2 Perl and C++......Page 463 B.2.2 Classes......Page 464 B.2.3 Methods......Page 465 B.2.7 Polymorphism......Page 466 B.2.8 Comparative syntax......Page 467 B.3.1 Objects......Page 469 B.3.3 Methods......Page 470 B.3.7 Polymorphism......Page 471 B.3.9 Comparative syntax......Page 472 B.4.2 Classes......Page 474 B.4.3 Methods......Page 475 B.4.6 Polymorphism......Page 476 B.4.9 Where to find out more......Page 477 glossary......Page 479 bibliography......Page 486 index......Page 488 "Perl is a great language for throw-away programming--hacking quick solutions to urgent tasks. It can also be a great language for developing large, robust and reusable solutions to real-life problems. The object-oriented techniques taught in this book will help you write cleaner, more readable and more maintainable Perl programs." "Whether you're a complete newcomer to object orientation, a refugee from C++, or just another Perl hacker looking to extend your skills, this book will take you from first principles to practical techniques, and on to the deepest mysteries of object orientation. Book jacket."--BOOK JACKET

Techniques and tricks to master basic and advanced OO Perl for programmers who already have basic to intermediate skills in procedural Perl.

Programmers who already have basic to intermediate skills in procedural Perl and understand fundamental concepts of object orientation will get a solid understanding of basic and advanced object-oriented Perl. This book clarifies when, where and why to use Perl. Featuring many techniques and tricks, it presents solutions to common programming problem and explains how to combine Perl and C++.