The Ruby Programming Language Book

Preface

1 Introduction 1

1.1 A Tour of Ruby 2

1.2 Try Ruby 11

1.3 About This Book 15

1.4 A Sudoku Solver in Ruby 17

2 The Structure and Execution of Ruby Programs 25

2.1 Lexical Structure 26

2.2 Syntactic Structure 33

2.3 File Structure 35

2.4 Program Encoding 36

2.5 Program Execution 39

3 Datatypes and Objects 41

3.1 Numbers 42

3.2 Text 46

3.3 Arrays 64

3.4 Hashes 67

3.5 Ranges 68

3.6 Symbols 71

3.7 True, False, and Nil 72

3.8 Objects 72

4 Expressions and Operators 85

4.1 Literals and Keyword Literals 86

4.2 Variable References 87

4.3 Constant References 88

4.4 Method Invocations 89

4.5 Assignments 92

4.6 Operators 100

5 Statements and Control Structures 117

5.1 Conditionals 118

5.2 Loops 127

5.3 Iterators and Enumerable Objects 130

5.4 Blocks 140

5.5 Altering Control Flow 146

5.6 Exceptions and Exception Handling 154

5.7 BEGIN and END 165

5.8 Threads, Fibers, and Continuations 166

6 Methods, Procs, Lambdas, and Closures 175

6.1 Defining Simple Methods 177

6.2 Method Names 180

6.3 Methods and Parentheses 183

6.4 Method Arguments 185

6.5 Procs and Lambdas 192

6.6 Closures 200

6.7 Method Objects 203

6.8 Functional Programming 205

7 Classes and Modules 213

7.1 Defining a Simple Class 214

7.2 Method Visibility: Public, Protected, Private 232

7.3 Subclassing and Inheritance 234

7.4 Object Creation and Initialization 241

7.5 Modules 247

7.6 Loading and Requiring Modules 252

7.7 Singleton Methods and the Eigenclass 257

7.8 Method Lookup 258

7.9 Constant Lookup 261

8 Reflection and Metaprogramming 265

8.1 Types, Classes, and Modules 266

8.2 Evaluating Strings and Blocks268

8.3 Variables and Constants 271

8.4 Methods 272

8.5 Hooks 277

8.6 Tracing 279

8.7 ObjectSpace and GC 281

8.8 Custom Control Structures 281

8.9 Missing Methods and Missing Constants 284

8.10 Dynamically Creating Methods 287

8.11 Alias Chaining 290

8.12 Domain-Specific Languages 296

9 The Ruby Platform 303

9.1 Strings 304

9.2 Regular Expressions 310

9.3 Numbers and Math 321

9.4 Dates and Times 325

9.5 Collections 328

9.6 Files and Directories 350

9.7 Input/Output 356

9.8 Networking 366

9.9 Threads and Concurrency 372

10 The Ruby Environment 389

10.1 Invoking the Ruby Interpreter 390

10.2 The Top-Level Environment 394

10.3 Practical Extraction and Reporting Shortcuts 403

10.4 Calling the OS 405

10.5 Security 409

Index 413