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The Rust Programming Language

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The Rust Programming Language The Rust Programming Language The Rust Team 2016-10-01 2 Contents 1 Introduction 11 Contributing ...................................... 11 2 Getting Started 13 Installing Rust ..................................... 13 Hello, world! ...................................... 16 Hello, Cargo! ...................................... 19 Closing Thoughts .................................... 23 3 Tutorial: Guessing Game 25 Set up .......................................... 25 Processing a Guess ................................... 26 Generating a secret number .............................. 30 Comparing guesses ................................... 33 Looping ......................................... 37 Complete! ........................................ 41 4 Syntax and Semantics 43 Variable Bindings ....................................... 43 Patterns ......................................... 43 Type annotations .................................... 44 Mutability ........................................ 44 Initializing bindings .................................. 45 Scope and shadowing .................................. 46 Functions ........................................... 48 Primitive Types ........................................ 53 Booleans ......................................... 53 4 CONTENTS char ........................................... 53 Numeric types ..................................... 54 Arrays .......................................... 55 Slices ........................................... 56 str ............................................ 56 Tuples .......................................... 57 Functions ........................................ 58 Comments ........................................... 58 if ................................................ 59 Loops ............................................. 60 Vectors ............................................ 64 Ownership ........................................... 67 Meta ........................................... 67 Ownership ........................................ 68 Move semantics ..................................... 68 More than ownership .................................. 71 References and Borrowing .................................. 72 Meta ........................................... 72 Borrowing ........................................ 72 &mut references .................................... 74 The Rules ........................................ 75 Lifetimes ........................................... 79 Meta ........................................... 79 Lifetimes ........................................ 80 In structs ........................................ 81 Mutability ........................................... 85 Interior vs. Exterior Mutability ............................ 86 Structs ............................................. 88 Update syntax ..................................... 90 Tuple structs ...................................... 91 Unit-like structs .................................... 92 Enums ............................................. 92 Constructors as functions ............................... 93 CONTENTS 5 Match ............................................. 94 Matching on enums ................................... 95 Patterns ............................................ 96 Multiple patterns .................................... 96 Destructuring ...................................... 97 Ignoring bindings .................................... 98 ref and ref mut ..................................... 99 Ranges .......................................... 100 Bindings ......................................... 100 Guards .......................................... 101 Mix and Match ..................................... 102 Method Syntax ........................................ 102 Method calls ...................................... 103 Chaining method calls ................................. 104 Associated functions .................................. 105 Builder Pattern ..................................... 106 Strings ............................................. 107 Generics ............................................ 110 Traits ............................................. 113 Rules for implementing traits ............................. 116 Multiple trait bounds ................................. 118 Where clause ...................................... 118 Default methods .................................... 120 Inheritance ....................................... 121 Deriving ......................................... 121 Drop .............................................. 122 if let .............................................. 123 Trait Objects ......................................... 124 Closures ............................................ 130 Syntax .......................................... 130 Closures and their environment ............................ 131 Closure implementation ................................ 134 Taking closures as arguments ............................. 134 6 CONTENTS Function pointers and closures ............................ 136 Returning closures ................................... 137 Universal Function Call Syntax ............................... 139 Angle-bracket Form .................................. 141 Crates and Modules ..................................... 142 Basic terminology: Crates and Modules ....................... 142 Defining Modules .................................... 143 Multiple File Crates .................................. 144 Importing External Crates ............................... 146 Exporting a Public Interface .............................. 146 Importing Modules with use .............................. 148 const and static ....................................... 152 static .......................................... 152 Initializing ........................................ 153 Which construct should I use? ............................. 153 Attributes ........................................... 153 type aliases .......................................... 154 Casting between types .................................... 155 Coercion ......................................... 155 as ............................................ 156 transmute ........................................ 158 Associated Types ....................................... 159 Unsized Types ........................................ 162 ?Sized .......................................... 162 Operators and Overloading ................................. 163 Using operator traits in generic structs ........................ 164 Deref coercions ........................................ 165 Macros ............................................. 167 Defining a macro .................................... 168 Hygiene ......................................... 171 Recursive macros .................................... 173 Debugging macro code ................................. 174 Syntactic requirements ................................. 174 CONTENTS 7 Scoping and macro import/export .......................... 176 The variable $crate .................................. 177 The deep end ...................................... 178 Common macros .................................... 178 Procedural macros ................................... 180 Raw Pointers ......................................... 180 Basics .......................................... 181 FFI ........................................... 182 References and raw pointers .............................. 182 unsafe ............................................. 183 What does ‘safe’ mean? ................................ 183 Unsafe Superpowers .................................. 184 5 Effective Rust 187 The Stack and the Heap ................................... 187 Memory management ................................. 187 The Stack ........................................ 188 The Heap ........................................ 191 Arguments and borrowing ............................... 193 A complex example ................................... 194 What do other languages do? ............................. 197 Which to use? ...................................... 198 Testing ............................................ 198 The test attribute ................................... 199 The ignore attribute .................................. 202 The tests module ................................... 203 The tests directory .................................. 205 Documentation tests .................................. 206 Conditional Compilation ................................... 207 cfg_attr ......................................... 208 cfg! ............................................ 209 Documentation ........................................ 209 Iterators ............................................ 220 Concurrency ......................................... 226 8 CONTENTS Error Handling ........................................ 234 Table of Contents .................................... 234 The Basics ....................................... 235 Working with multiple error types .......................... 245 Standard library traits used for error handling .................... 252 Case study: A program to read population data ................... 259 The Short Story .................................... 271 Choosing your Guarantees .................................. 272 Basic pointer types ................................... 272 Cell types ........................................ 274 Synchronous types ..................................
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