Swift Developer's Cookbook (includes Content Update Program), The

Erica Sadun is a bestselling author, coauthor, and contributor to several dozen books on programming and other digital topics. She has blogged at TUAW.com, O'Reilly's Mac Devcenter, Lifehacker, and Ars Technica. In addition to being the author of dozens of iOS-native applications, Erica holds a Ph.D. in computer science from Georgia Tech's Graphics, Visualization and Usability Center. A geek, a programmer, and an author, she's never met a gadget she didn't love. When not writing, she and her geek husband have parented three geeks-in-training, who regard their parents with restrained bemusement, when they're not busy rewiring the house or plotting global domination.

Preface xiii
How This Book Is Organized xiii
About the Sample Code xiv
Contacting the Author xv
Chapter 1: Welcome to Modern Swift 1
Migrating Code 2
How to Migrate 2
Migration Lessons 4
Using Swift 4
Compiled Applications 4
Frameworks and Libraries 5
Scripting 5
REPL 6
Playgrounds 7
Other Swift 8
Learning Swift 8
Wrap-up 9
Chapter 2: Printing and Mirroring 11
Basic Printing 11
Printing Multiple Items 12
Adding Item Separators 13
String Interpolation 13
Controlling Line Feeds 14
Recipe: Printing to Custom Destinations 15
Printing to Strings 16
Printing to Custom Output Streams 17
Recipe: Printing and String Formats 18
Swift and Format Specifiers 19
Format Limitations 19
Conditional Compilation 20
Debug Printing 21
Custom Stream Output 21
Recipe: Postfix Printing 23
Quick Looks 24
Quick Look for Custom Types 24
Quick Looks for Custom Types in Playgrounds 25
Playground Quick Looks 25
Creating Custom Quick Looks for Playgrounds 26
Built-in Quick Look Types 27
Third-Party Rendering 28
Using Dump Functions 30
Building Custom Mirrors 31
Recursive Reflection 32
Building Basic Mirror Descriptions Using Protocol Conformance 33
Adding Header Docs 35
Building Header Documentation 35
Markdown Support 36
Keywords 37
Special Swift Concerns 40
Adding Images to Header Docs 40
Wrap-up 41
Chapter 3: Optionals?! 43
Optionals 101 43
Unwrapping Optionals 45
Forced Unwrapping 45
Conditional Binding 46
Conditional Binding and Type Casts 46
Binding Cascades 48
guard Statements 50
Implicitly Unwrapped Optionals 51
Guarding Failable Initializers 52
Optionals and Sentinel Values 53
Coalescing 55
Optional Assignment 55
Optional Patterns 56
Optional Chaining 58
Selector Testing and Optional Chaining 59
Subscripts 60
Optional Mapping 61
Maps and Chaining 61
Filtering nil Values with flatMap 62
Unmanaged Wrappers 62
Wrap-up 64
Chapter 4: Closures and Functions 65
Building a Function 65
Parameter Names 66
Label Conventions 66
Naming Methods and Functions 68
External and Local Parameters 69
Defaults 70
Constant and Variable Parameters 71
Modifying Parameters 72
Closures and Functions 73
Function Types 73
Using Tuple Arguments 74
Using Shorthand Argument Names 74
Inferred Closure Types 76
Parameter Type Inference 77
Declaring Type Aliases 78
Nested Functions 79
Tuples 80
From Tuples to Structs 82
Tuple Return Types 82
Variadic Parameters 83
Capturing Values 85
Autoclosures 87
Adding Default Closures 90
Currying 91
Why Curry? 92
Building Libraries 92
Partial Application 93
Currying Costs 94
Currying and Callbacks 94
Practical Currying 95
Passing Closures as Function Parameters 97
Wrap-up 99
Chapter 5: Generics and Protocols 101
Expanding to Generics 101
Protocols 102
Tokens 103
Type Constraints 104
Adopting Protocols 104
Declaring Protocols 105
Member Declarations 107
Building a Basic Protocol 109
Adding Protocol Default Implementations 110
Optional Protocol Requirements 111
Swift-Native Optional Protocol Requirements 112
Building Generic Types 113
Type Parameters 113
Generic Requirements 114
Conformance Requirements 115
Recipe: Same-Type Requirements 115
Generic Beautification 117
Legal Tokens 117
Matching Aliases 118
Protocol Alias Defaults 119
Collating Associated Types 119
Extending Generic Types 120
Using Protocols as Types 121
Protocol-Based Collections 121
Self Requirements 122
Protocol Objects and Self Requirements 123
Leveraging Protocols 124
Wrap-up 124
Chapter 6: Errors 125
Failing Hard 125
Fatal Errors 126
Assertions 126
Preconditions 127
Aborting and Exiting 128
Failing Gracefully 128
The ErrorType Protocol 129
Choosing Between Optionals and Error Handling 130
Swift Error Rules 130
Rule 1: Move Away from nil Sentinels 131
Rule 2: Use throw to Raise Errors 132
Rule 3: Use Error Types with Visible Access 133
Rule 4: Mark All Error-Participating Methods with throws 134
Rule 5: Use rethrows Consistently 134
Rule 6: Consume Errors Where They Matter 135
Rule 7: Terminate Threaded Error Chains 135
Building Errors 137
Good Errors 138
Naming Your Errors 138
Adding String Descriptions 139
Adding Reasons 139
Simplifying Output 140
Extending String 140
Type-Specific Errors 141
Retrieving Context 141
Contextualizing Strings 142
Contextualizing Throwing Types 143
Simplifying Contexts 144
Calling Throwing Functions 145
Using try 145
Error Propagation 147
Using try! 148
Using try? 148
Implementing Alternatives to try? 149
Guarding Results 151
Building a Printing Version of try? 151
Working with guard and defer 151
Wrap-up 153
Chapter 7: Types 155
Language Concepts 155
Reference and Value Types 155
Copy-and-Write-Back 156
Algebraic Data Types 157
Other Terminology 158
Enumerations 159
Basic Enumerations 159
Using Hash Values to Support Ranges 160
Raw Value Enumerations 162
Raw Value Members and Sequences 163
Associated Values 164
Indirect Values 165
Switches 166
Branching 166
Breaks 167
Fallthroughs 167
Complex Cases 169
Tuples 169
Pattern Matching with Value Bindings 169
where Clauses 170
Unwrapping Optional Enumerations 171
Embedding Values by Type 172
Option Sets 174
Revisiting NS_OPTIONS 174
Building Enumerations 175
Building Option Sets 176
Viewing Options 176
Classes 177
Optimization 178
Initializers 178
Initialization Steps 179
Designated and Convenience Initializers 179
Initialization Rules 179
Building Convenience Initializers 181
Failable and Throwing Initializers 181
Deinitializers 183
Property Observers 184
Getters/Setters and Access-Level Modifiers 185
Extensions and Overrides 186
Lazy Evaluation 187
Lazy Sequences 187
Lazy Properties 188
Wrap-up 188
Chapter 8: Miscellany 189
Statement Labels 189
Custom Operators 190
Declaring Operators 191
Conforming with Operators 192
Evaluating Operator Trade-offs 192
Array Indexing 193
Multi-indexed Array Access 194
Wrapped Indices 195
Array Slices 195
General Subscripting 196
Parameter-less Subscripting 197
String Utilities 198
Repeat Initializers 198
Strings and Radix 198
String Ranges 199
String Splitting 201
String Subscripts 201
Foundation Interoperability 203
Joining and Extending 203
Permutation Generator 203
Wrap-up 205
Index 207