[
  {
    "path": "CONTRIBUTING.markdown",
    "content": "\n\n# Contributing to the Official raywenderlich.com Swift Style Guide.\n\nThis style guide is a living document that evolves with the Swift language. It is different from others you may see, because the focus is centered on readability for print and the web. We created this style guide to keep the code in our books, tutorials, and starter kits nice and consistent — even though we have many different authors working on the books.\n\nWe appreciate and encourage contributions from the community that improve this document and hence the quality of tutorials we produce.  This document outlines the process for making contributions to the guide.\n\n**Note:** You are responsible for adding your name to the list of contributors should you desire.\n\n## Fixing Typos\n\nUncontroversial, non-additive changes such as misspellings, grammar or compiler errors can be fixed by simply issuing a pull request to master. The maintainer will merge the pull request or, if it is deemed \"controversial\" request the contributor open an issue so that other members of the community can participate in the discussion.\n\n## Style Changes \n\nAuthors at RayWenderlich.com are expected to follow all of the rules in this style guide unless special circumstances apply.  Because of this, it is important that updates happen at predictable times.  Be aware in advance that there may be a significant delay (many months) before a suggestion is ratified on the master branch.\n### Step 1: Open an Issue\n\nOpen an issue on github and describe the change you would like to see or rule that you would like to have added.  You can even propose the exact change in github markdown which can be pasted into the guide.\n### Step 2: Wait for Community Feedback\n\nWait for feedback on the issue. Even if the feedback is negative, don't close the issue too quickly.  Often times the discussion itself can be useful and give way to something even better.  Style guides are very subjective and it is important to always be respectful.  We expect participants to follow the same community guidelines as the Swift project itself outlined at [contributor-covenant.org](https://contributor-covenant.org)\n### Step 3: Wait for Maintainer Go Ahead\n\nThe maintainer will decide if a change is go or no go.  This decision is not necessarily based on the feedback of the community, but will often play a role. If you believe that the maintainer is mistaken, you can appeal the decision by just asking them. At this point the maintainer will poll the RayWenderlich team leads for a final decision with RayWenderlich acting as tie breaker if required.  Apologies in advance if your style suggestion isn't accepted.  You are always welcome, however, to make your own style guide for your organization or community! \n### Step 4: Create a Pull Request on the Update branch\n\nGiven the go ahead from the maintainer, create a pull request on the update branch in the repo.  There should be one of these.  If it is not clear what it is, ask the maintainer.  The current update branch is `update.`\n### Step 5: Branch Merged\n\nAt this point your involvement is complete. The maintainer will merge your PR to the update branch.\n### Step 6: Update Branch Reviewed\n\nThe RayWenderlich.com team has a chance to look at the final updated document before it is merged to master.  If an objection is raised, as with the appeal process, teams leads will deliberate on the final decision.\n\n### Step 7: Update Branch Merged to Master\n\nHurray!\n"
  },
  {
    "path": "CREDITS.markdown",
    "content": "## Credits\n\n[Richard Critz](https://github.com/rcritz) currently maintains this style guide.\nIt is a collaborative effort from the most stylish raywenderlich.com team members and its community: \n\n* [Jawwad Ahmad](https://github.com/jawwad)\n* [Soheil Moayedi Azarpour](https://github.com/moayes)\n* [Scott Berrevoets](https://github.com/Scott90)\n* [Jessy Catterwaul](https://github.com/JessyCatterwaul)\n* [Eric Cerney](https://github.com/ecerney)\n* [Sam Davies](https://github.com/sammyd)\n* [Evan Dekhayser](https://github.com/edekhayser)\n* [Jean-Pierre Distler](https://github.com/pdistler)\n* [Colin Eberhardt](https://github.com/ColinEberhardt)\n* [Vadim Eisenberg](https://github.com/vadimeisenbergibm)\n* [Ray Fix](https://github.com/rayfix)\n* [Joshua Greene](https://github.com/JRG-Developer)\n* [Robert Gummesson](https://github.com/RobertGummesson)\n* [Greg Heo](https://github.com/gregheo)\n* [Matthijs Hollemans](https://github.com/hollance)\n* [Erik Kerber](https://github.com/eskerber)\n* [Christopher LaPollo](https://github.com/elephantronic)\n* [Ben Morrow](https://github.com/benmorrow)\n* [Andy Pereira](https://github.com/macandyp)\n* [Ryan Nystrom](https://github.com/rnystrom)\n* [Andy Obusek](https://github.com/obuseme)\n* [Cesare Rocchi](https://github.com/funkyboy)\n* [Ellen Shapiro](https://github.com/designatednerd)\n* [Marin Todorov](https://github.com/icanzilb)\n* [Chris Wagner](https://github.com/cwagdev)\n* [Ray Wenderlich](https://github.com/rwenderlich)\n* [Jack Wu](https://github.com/jackwu95)\n* [Richard Critz](https://github.com/rcritz)\n\nHat tip to [Nicholas Waynik](https://github.com/ndubbs) and the [Objective-C Style Guide](https://github.com/raywenderlich/objective-c-style-guide) team!\n"
  },
  {
    "path": "LICENSE.txt",
    "content": "\nThis style guide is available under the MIT license:\n\nCopyright (c) 2024 Kodeco Inc.\n\nPermission is hereby granted, free of charge, to any person obtaining a copy\nof this software and associated documentation files (the \"Software\"), to deal\nin the Software without restriction, including without limitation the rights\nto use, copy, modify, merge, publish, distribute, sublicense, and/or sell\ncopies of the Software, and to permit persons to whom the Software is\nfurnished to do so, subject to the following conditions:\n\nThe above copyright notice and this permission notice shall be included in\nall copies or substantial portions of the Software.\n\nTHE SOFTWARE IS PROVIDED \"AS IS\", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR\nIMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,\nFITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE\nAUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER\nLIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,\nOUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN\nTHE SOFTWARE.\n"
  },
  {
    "path": "README.markdown",
    "content": "# The Official Kodeco Swift Style Guide.\n### Updated for Swift 5\n\nThis style guide is different from others you may see, because the focus is centered on readability for print and the web. We created this style guide to keep the code in our books, tutorials, and starter kits nice and consistent — even though we have many different authors working on the books.\n\nOur overarching goals are clarity, consistency and brevity, in that order.\n\n## Table of Contents\n\n* [Correctness](#correctness)\n* [Using SwiftLint](#using-swiftlint)\n* [Naming](#naming)\n  * [Prose](#prose)\n  * [Delegates](#delegates)\n  * [Use Type Inferred Context](#use-type-inferred-context)\n  * [Generics](#generics)\n  * [Class Prefixes](#class-prefixes)\n  * [Language](#language)\n* [Code Organization](#code-organization)\n  * [Protocol Conformance](#protocol-conformance)\n  * [Unused Code](#unused-code)\n  * [Minimal Imports](#minimal-imports)\n* [Spacing](#spacing)\n* [Comments](#comments)\n* [Classes and Structures](#classes-and-structures)\n  * [Use of Self](#use-of-self)\n  * [Protocol Conformance](#protocol-conformance)\n  * [Computed Properties](#computed-properties)\n  * [Final](#final)\n* [Function Declarations](#function-declarations)\n* [Function Calls](#function-calls)\n* [Closure Expressions](#closure-expressions)\n* [Types](#types)\n  * [Constants](#constants)\n  * [Static Methods and Variable Type Properties](#static-methods-and-variable-type-properties)\n  * [Optionals](#optionals)\n  * [Lazy Initialization](#lazy-initialization)\n  * [Type Inference](#type-inference)\n  * [Syntactic Sugar](#syntactic-sugar)\n* [Functions vs Methods](#functions-vs-methods)\n* [Memory Management](#memory-management)\n  * [Extending Object Lifetime](#extending-object-lifetime)\n* [Access Control](#access-control)\n* [Control Flow](#control-flow)\n  * [Ternary Operator](#ternary-operator)\n* [Golden Path](#golden-path)\n  * [Failing Guards](#failing-guards)\n* [Semicolons](#semicolons)\n* [Parentheses](#parentheses)\n* [Multi-line String Literals](#multi-line-string-literals)\n* [No Emoji](#no-emoji)\n* [No #imageLiteral or #colorLiteral](#no-imageliteral-or-colorliteral)\n* [Organization and Bundle Identifier](#organization-and-bundle-identifier)\n* [Copyright Statement](#copyright-statement)\n* [Smiley Face](#smiley-face)\n* [References](#references)\n\n\n## Correctness\n\nStrive to make your code compile without warnings. This rule informs many style decisions such as using `#selector` types instead of string literals.\n\n## Using SwiftLint\n\nWhen writing for Kodeco, you are strongly encouraged — perhaps even required, depending on your team — to use our SwiftLint configuration. See the [SwiftLint Policy](SWIFTLINT.markdown) for more information.\n\n## Naming\n\nDescriptive and consistent naming makes software easier to read and understand. Use the Swift naming conventions described in the [API Design Guidelines](https://swift.org/documentation/api-design-guidelines/). Some key takeaways include:\n\n- striving for clarity at the call site\n- prioritizing clarity over brevity\n- using `camelCase` (not `snake_case`)\n- using `UpperCamelCase` for types and protocols, `lowerCamelCase` for everything else\n- including all needed words while omitting needless words\n- using names based on roles, not types\n- sometimes compensating for weak type information\n- striving for fluent usage\n- beginning factory methods with `make`\n- naming methods for their side effects\n  - verb methods follow the -ed, -ing rule for the non-mutating version\n  - noun methods follow the formX rule for the mutating version\n  - boolean types should read like assertions\n  - protocols that describe _what something is_ should read as nouns\n  - protocols that describe _a capability_ should end in _-able_ or _-ible_\n- using terms that don't surprise experts or confuse beginners\n- generally avoiding abbreviations\n- using precedent for names\n- preferring methods and properties to free functions\n- casing acronyms and initialisms uniformly up or down\n- giving the same base name to methods that share the same meaning\n- avoiding overloads on return type\n- choosing good parameter names that serve as documentation\n- preferring to name the first parameter instead of including its name in the method name, except as mentioned under Delegates\n- labeling closure and tuple parameters\n- taking advantage of default parameters\n\n### Prose\n\nWhen referring to methods in prose, being unambiguous is critical. To refer to a method name, use the simplest form possible.\n\n1. Write the method name with no parameters.  **Example:** Next, you need to call `addTarget`.\n2. Write the method name with argument labels.  **Example:** Next, you need to call `addTarget(_:action:)`.\n3. Write the full method name with argument labels and types. **Example:** Next, you need to call `addTarget(_: Any?, action: Selector?)`.\n\nFor the above example using `UIGestureRecognizer`, 1 is unambiguous and preferred.\n\n**Pro Tip:** You can use Xcode's jump bar to lookup methods with argument labels. If you’re particularly good at mashing lots of keys simultaneously, put the cursor in the method name and press **Shift-Control-Option-Command-C** (all 4 modifier keys) and Xcode will kindly put the signature on your clipboard.\n\n![Methods in Xcode jump bar](screens/xcode-jump-bar.png)\n\n\n### Class Prefixes\n\nSwift types are automatically namespaced by the module that contains them and you should not add a class prefix such as RW. If two names from different modules collide you can disambiguate by prefixing the type name with the module name. However, only specify the module name when there is possibility for confusion, which should be rare.\n\n```swift\nimport SomeModule\n\nlet myClass = MyModule.UsefulClass()\n```\n\n### Delegates\n\nWhen creating custom delegate methods, an unnamed first parameter should be the delegate source. (UIKit contains numerous examples of this.)\n\n**Preferred**:\n```swift\nfunc namePickerView(_ namePickerView: NamePickerView, didSelectName name: String)\nfunc namePickerViewShouldReload(_ namePickerView: NamePickerView) -> Bool\n```\n\n**Not Preferred**:\n```swift\nfunc didSelectName(namePicker: NamePickerViewController, name: String)\nfunc namePickerShouldReload() -> Bool\n```\n\n### Use Type Inferred Context\n\nUse compiler inferred context to write shorter, clear code.  (Also see [Type Inference](#type-inference).)\n\n**Preferred**:\n```swift\nlet selector = #selector(viewDidLoad)\nview.backgroundColor = .red\nlet toView = context.view(forKey: .to)\nlet view = UIView(frame: .zero)\n```\n\n**Not Preferred**:\n```swift\nlet selector = #selector(ViewController.viewDidLoad)\nview.backgroundColor = UIColor.red\nlet toView = context.view(forKey: UITransitionContextViewKey.to)\nlet view = UIView(frame: CGRect.zero)\n```\n\n### Generics\n\nGeneric type parameters should be descriptive, upper camel case names. When a type name doesn't have a meaningful relationship or role, use a traditional single uppercase letter such as `T`, `U`, or `V`.\n\n**Preferred**:\n```swift\nstruct Stack<Element> { ... }\nfunc write<Target: OutputStream>(to target: inout Target)\nfunc swap<T>(_ a: inout T, _ b: inout T)\n```\n\n**Not Preferred**:\n```swift\nstruct Stack<T> { ... }\nfunc write<target: OutputStream>(to target: inout target)\nfunc swap<Thing>(_ a: inout Thing, _ b: inout Thing)\n```\n\n### Language\n\nUse US English spelling to match Apple's API.\n\n**Preferred**:\n```swift\nlet color = \"red\"\n```\n\n**Not Preferred**:\n```swift\nlet colour = \"red\"\n```\n\n## Code Organization\n\nUse extensions to organize your code into logical blocks of functionality. Each extension should be set off with a `// MARK: -` comment to keep things well-organized.\n\n### Protocol Conformance\n\nIn particular, when adding protocol conformance to a model, prefer adding a separate extension for the protocol methods. This keeps the related methods grouped together with the protocol and can simplify instructions to add a protocol to a class with its associated methods.\n\n**Preferred**:\n```swift\nclass MyViewController: UIViewController {\n  // class stuff here\n}\n\n// MARK: - UITableViewDataSource\nextension MyViewController: UITableViewDataSource {\n  // table view data source methods\n}\n\n// MARK: - UIScrollViewDelegate\nextension MyViewController: UIScrollViewDelegate {\n  // scroll view delegate methods\n}\n```\n\n**Not Preferred**:\n```swift\nclass MyViewController: UIViewController, UITableViewDataSource, UIScrollViewDelegate {\n  // all methods\n}\n```\n\nSince the compiler does not allow you to re-declare protocol conformance in a derived class, it is not always required to replicate the extension groups of the base class. This is especially true if the derived class is a terminal class and a small number of methods are being overridden. When to preserve the extension groups is left to the discretion of the author.\n\nFor UIKit view controllers, consider grouping lifecycle, custom accessors, and IBAction in separate class extensions.\n\n### Unused Code\n\nUnused (dead) code, including Xcode template code and placeholder comments should be removed. An exception is when your tutorial or book instructs the user to use the commented code.\n\nAspirational methods not directly associated with the tutorial whose implementation simply calls the superclass should also be removed. This includes any empty/unused UIApplicationDelegate methods.\n\n**Preferred**:\n```swift\noverride func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {\n  return Database.contacts.count\n}\n```\n\n**Not Preferred**:\n```swift\noverride func didReceiveMemoryWarning() {\n  super.didReceiveMemoryWarning()\n  // Dispose of any resources that can be recreated.\n}\n\noverride func numberOfSections(in tableView: UITableView) -> Int {\n  // #warning Incomplete implementation, return the number of sections\n  return 1\n}\n\noverride func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {\n  // #warning Incomplete implementation, return the number of rows\n  return Database.contacts.count\n}\n\n```\n### Minimal Imports\n\nImport only the modules a source file requires. For example, don't import `UIKit` when importing `Foundation` will suffice. Likewise, don't import `Foundation` if you must import `UIKit`.\n\n**Preferred**:\n```swift\nimport UIKit\nvar view: UIView\nvar deviceModels: [String]\n```\n\n**Preferred**:\n```swift\nimport Foundation\nvar deviceModels: [String]\n```\n\n**Not Preferred**:\n```swift\nimport UIKit\nimport Foundation\nvar view: UIView\nvar deviceModels: [String]\n```\n\n**Not Preferred**:\n```swift\nimport UIKit\nvar deviceModels: [String]\n```\n\n## Spacing\n\n* Indent using 2 spaces rather than tabs to conserve space and help prevent line wrapping. Be sure to set this preference in Xcode and in the Project settings as shown below:\n\n![Xcode indent settings](screens/indentation.png)\n\n* Method braces and other braces (`if`/`else`/`switch`/`while` etc.) always open on the same line as the statement but close on a new line.\n* Tip: You can re-indent by selecting some code (or **Command-A** to select all) and then **Control-I** (or **Editor ▸ Structure ▸ Re-Indent** in the menu). Some of the Xcode template code will have 4-space tabs hard coded, so this is a good way to fix that.\n\n**Preferred**:\n```swift\nif user.isHappy {\n  // Do something\n} else {\n  // Do something else\n}\n```\n\n**Not Preferred**:\n```swift\nif user.isHappy\n{\n  // Do something\n}\nelse {\n  // Do something else\n}\n```\n\n* There should be one blank line between methods and up to one blank line between type declarations to aid in visual clarity and organization. Whitespace within methods should separate functionality, but having too many sections in a method often means you should refactor into several methods.\n\n* There should be no blank lines after an opening brace or before a closing brace.\n\n* Closing parentheses should not appear on a line by themselves.\n\n**Preferred**:\n```swift\nlet user = try await getUser(\n  for: userID,\n  on: connection)\n```\n\n**Not Preferred**:\n```swift\nlet user = try await getUser(\n  for: userID,\n  on: connection\n)\n```\n\n* Colons always have no space on the left and one space on the right. Exceptions are the ternary operator `? :`, empty dictionary `[:]` and `#selector` syntax `addTarget(_:action:)`.\n\n**Preferred**:\n```swift\nclass TestDatabase: Database {\n  var data: [String: CGFloat] = [\"A\": 1.2, \"B\": 3.2]\n}\n```\n\n**Not Preferred**:\n```swift\nclass TestDatabase : Database {\n  var data :[String:CGFloat] = [\"A\" : 1.2, \"B\":3.2]\n}\n```\n\n* Long lines should be wrapped at around 70 characters. A hard limit is intentionally not specified.\n\n* Avoid trailing whitespaces at the ends of lines.\n\n* Add a single newline character at the end of each file.\n\n## Comments\n\nWhen they are needed, use comments to explain **why** a particular piece of code does something. Comments must be kept up-to-date or deleted.\n\nAvoid block comments inline with code, as the code should be as self-documenting as possible. _Exception: This does not apply to those comments used to generate documentation._\n\nAvoid the use of C-style comments (`/* ... */`). Prefer the use of double- or triple-slash.\n\n## Classes and Structures\n\n### Which one to use?\n\nRemember, structs have [value semantics](https://developer.apple.com/library/mac/documentation/Swift/Conceptual/Swift_Programming_Language/ClassesAndStructures.html#//apple_ref/doc/uid/TP40014097-CH13-XID_144). Use structs for things that do not have an identity. An array that contains [a, b, c] is really the same as another array that contains [a, b, c] and they are completely interchangeable. It doesn't matter whether you use the first array or the second, because they represent the exact same thing. That's why arrays are structs.\n\nClasses have [reference semantics](https://developer.apple.com/library/mac/documentation/Swift/Conceptual/Swift_Programming_Language/ClassesAndStructures.html#//apple_ref/doc/uid/TP40014097-CH13-XID_145). Use classes for things that do have an identity or a specific life cycle. You would model a person as a class because two person objects are two different things. Just because two people have the same name and birthdate, doesn't mean they are the same person. But the person's birthdate would be a struct because a date of 3 March 1950 is the same as any other date object for 3 March 1950. The date itself doesn't have an identity.\n\nSometimes, things should be structs but need to conform to `AnyObject` or are historically modeled as classes already (`NSDate`, `NSSet`). Try to follow these guidelines as closely as possible.\n\n### Example definition\n\nHere's an example of a well-styled class definition:\n\n```swift\nclass Circle: Shape {\n  var x: Int, y: Int\n  var radius: Double\n  var diameter: Double {\n    get {\n      return radius * 2\n    }\n    set {\n      radius = newValue / 2\n    }\n  }\n\n  init(x: Int, y: Int, radius: Double) {\n    self.x = x\n    self.y = y\n    self.radius = radius\n  }\n\n  convenience init(x: Int, y: Int, diameter: Double) {\n    self.init(x: x, y: y, radius: diameter / 2)\n  }\n\n  override func area() -> Double {\n    return Double.pi * radius * radius\n  }\n}\n\nextension Circle: CustomStringConvertible {\n  var description: String {\n    return \"center = \\(centerString) area = \\(area())\"\n  }\n  private var centerString: String {\n    return \"(\\(x),\\(y))\"\n  }\n}\n```\n\nThe example above demonstrates the following style guidelines:\n\n + Specify types for properties, variables, constants, argument declarations and other statements with a space after the colon but not before, e.g. `x: Int`, and `Circle: Shape`.\n + Define multiple variables and structures on a single line if they share a common purpose / context.\n + Indent getter and setter definitions and property observers.\n + Don't add modifiers such as `internal` when they're already the default. Similarly, don't repeat the access modifier when overriding a method.\n + Organize extra functionality (e.g. printing) in extensions.\n + Hide non-shared, implementation details such as `centerString` inside the extension using `private` access control.\n\n### Use of Self\n\nFor conciseness, avoid using `self` since Swift does not require it to access an object's properties or invoke its methods.\n\nUse self only when required by the compiler (in `@escaping` closures, or in initializers to disambiguate properties from arguments). In other words, if it compiles without `self` then omit it.\n\n\n### Computed Properties\n\nFor conciseness, if a computed property is read-only, omit the get clause. The get clause is required only when a set clause is provided.\n\n**Preferred**:\n```swift\nvar diameter: Double {\n  return radius * 2\n}\n```\n\n**Not Preferred**:\n```swift\nvar diameter: Double {\n  get {\n    return radius * 2\n  }\n}\n```\n\n### Final\n\nMarking classes or members as `final` in tutorials can distract from the main topic and is not required. Nevertheless, use of `final` can sometimes clarify your intent and is worth the cost. In the below example, `Box` has a particular purpose and customization in a derived class is not intended. Marking it `final` makes that clear.\n\n```swift\n// Turn any generic type into a reference type using this Box class.\nfinal class Box<T> {\n  let value: T\n  init(_ value: T) {\n    self.value = value\n  }\n}\n```\n\n## Function Declarations\n\nKeep short function declarations on one line including the opening brace:\n\n```swift\nfunc reticulateSplines(spline: [Double]) -> Bool {\n  // reticulate code goes here\n}\n```\n\nFor functions with long signatures, put each parameter on a new line and add an extra indent on subsequent lines:\n\n```swift\nfunc reticulateSplines(\n  spline: [Double], \n  adjustmentFactor: Double,\n  translateConstant: Int, \n  comment: String\n) -> Bool {\n  // reticulate code goes here\n}\n```\n\nDon't use `(Void)` to represent the lack of an input; simply use `()`. Use `Void` instead of `()` for closure and function outputs.\n\n**Preferred**:\n\n```swift\nfunc updateConstraints() -> Void {\n  // magic happens here\n}\n\ntypealias CompletionHandler = (result) -> Void\n```\n\n**Not Preferred**:\n\n```swift\nfunc updateConstraints() -> () {\n  // magic happens here\n}\n\ntypealias CompletionHandler = (result) -> ()\n```\n\n## Function Calls\n\nMirror the style of function declarations at call sites. Calls that fit on a single line should be written as such:\n\n```swift\nlet success = reticulateSplines(splines)\n```\n\nIf the call site must be wrapped, put each parameter on a new line, indented one additional level:\n\n```swift\nlet success = reticulateSplines(\n  spline: splines,\n  adjustmentFactor: 1.3,\n  translateConstant: 2,\n  comment: \"normalize the display\")\n```\n\n## Closure Expressions\n\nUse trailing closure syntax only if there's a single closure expression parameter at the end of the argument list. Give the closure parameters descriptive names.\n\n**Preferred**:\n```swift\nUIView.animate(withDuration: 1.0) {\n  self.myView.alpha = 0\n}\n\nUIView.animate(withDuration: 1.0, animations: {\n  self.myView.alpha = 0\n}, completion: { finished in\n  self.myView.removeFromSuperview()\n})\n```\n\n**Not Preferred**:\n```swift\nUIView.animate(withDuration: 1.0, animations: {\n  self.myView.alpha = 0\n})\n\nUIView.animate(withDuration: 1.0, animations: {\n  self.myView.alpha = 0\n}) { f in\n  self.myView.removeFromSuperview()\n}\n```\n\nFor single-expression closures where the context is clear, use implicit returns:\n\n```swift\nattendeeList.sort { a, b in\n  a > b\n}\n```\n\nChained methods using trailing closures should be clear and easy to read in context. Decisions on spacing, line breaks, and when to use named versus anonymous arguments is left to the discretion of the author. Examples:\n\n```swift\nlet value = numbers.map { $0 * 2 }.filter { $0 % 3 == 0 }.index(of: 90)\n\nlet value = numbers\n  .map {$0 * 2}\n  .filter {$0 > 50}\n  .map {$0 + 10}\n```\n\n## Types\n\nAlways use Swift's native types and expressions when available. Swift offers bridging to Objective-C so you can still use the full set of methods as needed.\n\n**Preferred**:\n```swift\nlet width = 120.0                                    // Double\nlet widthString = \"\\(width)\"                         // String\n```\n\n**Less Preferred**:\n```swift\nlet width = 120.0                                    // Double\nlet widthString = (width as NSNumber).stringValue    // String\n```\n\n**Not Preferred**:\n```swift\nlet width: NSNumber = 120.0                          // NSNumber\nlet widthString: NSString = width.stringValue        // NSString\n```\n\nIn drawing code, use `CGFloat` if it makes the code more succinct by avoiding too many conversions.\n\n### Constants\n\nConstants are defined using the `let` keyword and variables with the `var` keyword. Always use `let` instead of `var` if the value of the variable will not change.\n\n**Tip:** A good technique is to define everything using `let` and only change it to `var` if the compiler complains!\n\nYou can define constants on a type rather than on an instance of that type using type properties. To declare a type property as a constant simply use `static let`. Type properties declared in this way are generally preferred over global constants because they are easier to distinguish from instance properties. Example:\n\n**Preferred**:\n```swift\nenum Math {\n  static let e = 2.718281828459045235360287\n  static let root2 = 1.41421356237309504880168872\n}\n\nlet hypotenuse = side * Math.root2\n\n```\n**Note:** The advantage of using a case-less enumeration is that it can't accidentally be instantiated and works as a pure namespace.\n\n**Not Preferred**:\n```swift\nlet e = 2.718281828459045235360287  // pollutes global namespace\nlet root2 = 1.41421356237309504880168872\n\nlet hypotenuse = side * root2 // what is root2?\n```\n\n### Static Methods and Variable Type Properties\n\nStatic methods and type properties work similarly to global functions and global variables and should be used sparingly. They are useful when functionality is scoped to a particular type or when Objective-C interoperability is required.\n\n### Optionals\n\nDeclare variables and function return types as optional with `?` where a `nil` value is acceptable.\n\nUse implicitly unwrapped types declared with `!` only for instance variables that you know will be initialized later before use, such as subviews that will be set up in `viewDidLoad()`. Prefer optional binding to implicitly unwrapped optionals in most other cases.\n\nWhen accessing an optional value, use optional chaining if the value is only accessed once or if there are many optionals in the chain:\n\n```swift\ntextContainer?.textLabel?.setNeedsDisplay()\n```\n\nUse optional binding when it's more convenient to unwrap once and perform multiple operations:\n\n```swift\nif let textContainer = textContainer {\n  // do many things with textContainer\n}\n\n```\n**Notes:** Swift 5.7 introduced new shorthand syntax for unwrapping optionals into shadowed variables:\n\n```swift\nif let textContainer {\n  // do many things with textContainer\n}\n```\n\nWhen naming optional variables and properties, avoid naming them like `optionalString` or `maybeView` since their optional-ness is already in the type declaration.\n\nFor optional binding, shadow the original name whenever possible rather than using names like `unwrappedView` or `actualLabel`.\n\n**Preferred**:\n```swift\nvar subview: UIView?\nvar volume: Double?\n\n// later on...\nif let subview = subview, let volume = volume {\n  // do something with unwrapped subview and volume\n}\n\n// another example\nresource.request().onComplete { [weak self] response in\n  guard let self = self else { return }\n  let model = self.updateModel(response)\n  self.updateUI(model)\n}\n```\n\n**Not Preferred**:\n```swift\nvar optionalSubview: UIView?\nvar volume: Double?\n\nif let unwrappedSubview = optionalSubview {\n  if let realVolume = volume {\n    // do something with unwrappedSubview and realVolume\n  }\n}\n\n// another example\nUIView.animate(withDuration: 2.0) { [weak self] in\n  guard let strongSelf = self else { return }\n  strongSelf.alpha = 1.0\n}\n```\n\n### Lazy Initialization\n\nConsider using lazy initialization for finer grained control over object lifetime. This is especially true for `UIViewController` that loads views lazily. You can either use a closure that is immediately called `{ }()` or call a private factory method. Example:\n\n```swift\nlazy var locationManager = makeLocationManager()\n\nprivate func makeLocationManager() -> CLLocationManager {\n  let manager = CLLocationManager()\n  manager.desiredAccuracy = kCLLocationAccuracyBest\n  manager.delegate = self\n  manager.requestAlwaysAuthorization()\n  return manager\n}\n```\n\n**Notes:**\n  - `[unowned self]` is not required here. A retain cycle is not created.\n  - Location manager has a side-effect for popping up UI to ask the user for permission so fine grain control makes sense here.\n\n\n### Type Inference\n\nPrefer compact code and let the compiler infer the type for constants or variables of single instances. Type inference is also appropriate for small, non-empty arrays and dictionaries. When required, specify the specific type such as `CGFloat` or `Int16`.\n\n**Preferred**:\n```swift\nlet message = \"Click the button\"\nlet currentBounds = computeViewBounds()\nvar names = [\"Mic\", \"Sam\", \"Christine\"]\nlet maximumWidth: CGFloat = 106.5\n```\n\n**Not Preferred**:\n```swift\nlet message: String = \"Click the button\"\nlet currentBounds: CGRect = computeViewBounds()\nvar names = [String]()\n```\n\n#### Type Annotation for Empty Arrays and Dictionaries\n\nFor empty arrays and dictionaries, use type annotation. (For an array or dictionary assigned to a large, multi-line literal, use type annotation.)\n\n**Preferred**:\n```swift\nvar names: [String] = []\nvar lookup: [String: Int] = [:]\n```\n\n**Not Preferred**:\n```swift\nvar names = [String]()\nvar lookup = [String: Int]()\n```\n\n**NOTE**: Following this guideline means picking descriptive names is even more important than before.\n\n\n### Syntactic Sugar\n\nPrefer the shortcut versions of type declarations over the full generics syntax.\n\n**Preferred**:\n```swift\nvar deviceModels: [String]\nvar employees: [Int: String]\nvar faxNumber: Int?\n```\n\n**Not Preferred**:\n```swift\nvar deviceModels: Array<String>\nvar employees: Dictionary<Int, String>\nvar faxNumber: Optional<Int>\n```\n\n## Functions vs Methods\n\nFree functions, which aren't attached to a class or type, should be used sparingly. When possible, prefer to use a method instead of a free function. This aids in readability and discoverability.\n\nFree functions are most appropriate when they aren't associated with any particular type or instance.\n\n**Preferred**\n```swift\nlet sorted = items.mergeSorted()  // easily discoverable\nrocket.launch()  // acts on the model\n```\n\n**Not Preferred**\n```swift\nlet sorted = mergeSort(items)  // hard to discover\nlaunch(&rocket)\n```\n\n**Free Function Exceptions**\n```swift\nlet tuples = zip(a, b)  // feels natural as a free function (symmetry)\nlet value = max(x, y, z)  // another free function that feels natural\n```\n\n## Memory Management\n\nCode (even non-production, tutorial demo code) should not create reference cycles. Analyze your object graph and prevent strong cycles with `weak` and `unowned` references. Alternatively, use value types (`struct`, `enum`) to prevent cycles altogether.\n\n### Extending object lifetime\n\nExtend object lifetime using the `[weak self]` and `guard let self = self else { return }` idiom. `[weak self]` is preferred to `[unowned self]` where it is not immediately obvious that `self` outlives the closure. Explicitly extending lifetime is preferred to optional chaining.\n\n**Preferred**\n```swift\nresource.request().onComplete { [weak self] response in\n  guard let self = self else {\n    return\n  }\n  let model = self.updateModel(response)\n  self.updateUI(model)\n}\n```\n\n**Not Preferred**\n```swift\n// might crash if self is released before response returns\nresource.request().onComplete { [unowned self] response in\n  let model = self.updateModel(response)\n  self.updateUI(model)\n}\n```\n\n**Not Preferred**\n```swift\n// deallocate could happen between updating the model and updating UI\nresource.request().onComplete { [weak self] response in\n  let model = self?.updateModel(response)\n  self?.updateUI(model)\n}\n```\n\n## Access Control\n\nFull access control annotation in tutorials can distract from the main topic and is not required. Using `private` and `fileprivate` appropriately, however, adds clarity and promotes encapsulation. Prefer `private` to `fileprivate`; use `fileprivate` only when the compiler insists.\n\nOnly explicitly use `open`, `public`, and `internal` when you require a full access control specification.\n\nUse access control as the leading property specifier. The only things that should come before access control are the `static` specifier or attributes such as `@IBAction`, `@IBOutlet` and `@discardableResult`.\n\n**Preferred**:\n```swift\nprivate let message = \"Great Scott!\"\n\nclass TimeMachine {  \n  private dynamic lazy var fluxCapacitor = FluxCapacitor()\n}\n```\n\n**Not Preferred**:\n```swift\nfileprivate let message = \"Great Scott!\"\n\nclass TimeMachine {  \n  lazy dynamic private var fluxCapacitor = FluxCapacitor()\n}\n```\n\n## Control Flow\n\nPrefer the `for-in` style of `for` loop over the `while-condition-increment` style.\n\n**Preferred**:\n```swift\nfor _ in 0..<3 {\n  print(\"Hello three times\")\n}\n\nfor (index, person) in attendeeList.enumerated() {\n  print(\"\\(person) is at position #\\(index)\")\n}\n\nfor index in stride(from: 0, to: items.count, by: 2) {\n  print(index)\n}\n\nfor index in (0...3).reversed() {\n  print(index)\n}\n```\n\n**Not Preferred**:\n```swift\nvar i = 0\nwhile i < 3 {\n  print(\"Hello three times\")\n  i += 1\n}\n\n\nvar i = 0\nwhile i < attendeeList.count {\n  let person = attendeeList[i]\n  print(\"\\(person) is at position #\\(i)\")\n  i += 1\n}\n```\n\n### Ternary Operator\n\nThe Ternary operator, `?:` , should only be used when it increases clarity or code neatness. A single condition is usually all that should be evaluated. Evaluating multiple conditions is usually more understandable as an `if` statement or refactored into instance variables. In general, the best use of the ternary operator is during assignment of a variable and deciding which value to use.\n\n**Preferred**:\n\n```swift\nlet value = 5\nresult = value != 0 ? x : y\n\nlet isHorizontal = true\nresult = isHorizontal ? x : y\n```\n\n**Not Preferred**:\n\n```swift\nresult = a > b ? x = c > d ? c : d : y\n```\n\n## Golden Path\n\nWhen coding with conditionals, the left-hand margin of the code should be the \"golden\" or \"happy\" path. That is, don't nest `if` statements. Multiple return statements are OK. The `guard` statement is built for this.\n\n**Preferred**:\n```swift\nfunc computeFFT(context: Context?, inputData: InputData?) throws -> Frequencies {\n  guard let context = context else {\n    throw FFTError.noContext\n  }\n  guard let inputData = inputData else {\n    throw FFTError.noInputData\n  }\n\n  // use context and input to compute the frequencies\n  return frequencies\n}\n```\n\n**Not Preferred**:\n```swift\nfunc computeFFT(context: Context?, inputData: InputData?) throws -> Frequencies {\n  if let context = context {\n    if let inputData = inputData {\n      // use context and input to compute the frequencies\n\n      return frequencies\n    } else {\n      throw FFTError.noInputData\n    }\n  } else {\n    throw FFTError.noContext\n  }\n}\n```\n\nWhen multiple optionals are unwrapped either with `guard` or `if let`, minimize nesting by using the compound version when possible. In the compound version, place the `guard` on its own line, then indent each condition on its own line. The `else` clause is indented to match the `guard` itself, as shown below. Example:\n\n**Preferred**:\n```swift\nguard \n  let number1 = number1,\n  let number2 = number2,\n  let number3 = number3 \nelse {\n  fatalError(\"impossible\")\n}\n// do something with numbers\n```\n\n**Not Preferred**:\n```swift\nif let number1 = number1 {\n  if let number2 = number2 {\n    if let number3 = number3 {\n      // do something with numbers\n    } else {\n      fatalError(\"impossible\")\n    }\n  } else {\n    fatalError(\"impossible\")\n  }\n} else {\n  fatalError(\"impossible\")\n}\n```\n\n### Failing Guards\n\nGuard statements are required to exit in some way. Generally, this should be simple one line statement such as `return`, `throw`, `break`, `continue`, and `fatalError()`. Large code blocks should be avoided. If cleanup code is required for multiple exit points, consider using a `defer` block to avoid cleanup code duplication.\n\n## Semicolons\n\nSwift does not require a semicolon after each statement in your code. They are only required if you wish to combine multiple statements on a single line.\n\nDo not write multiple statements on a single line separated with semicolons.\n\n**Preferred**:\n```swift\nlet swift = \"not a scripting language\"\n```\n\n**Not Preferred**:\n```swift\nlet swift = \"not a scripting language\";\n```\n\n**NOTE**: Swift is very different from JavaScript, where omitting semicolons is [generally considered unsafe](https://stackoverflow.com/questions/444080/do-you-recommend-using-semicolons-after-every-statement-in-javascript)\n\n## Parentheses\n\nParentheses around conditionals are not required and should be omitted.\n\n**Preferred**:\n```swift\nif name == \"Hello\" {\n  print(\"World\")\n}\n```\n\n**Not Preferred**:\n```swift\nif (name == \"Hello\") {\n  print(\"World\")\n}\n```\n\nIn larger expressions, optional parentheses can sometimes make code read more clearly.\n\n**Preferred**:\n```swift\nlet playerMark = (player == current ? \"X\" : \"O\")\n```\n\n## Multi-line String Literals\n\nWhen building a long string literal, you're encouraged to use the multi-line string literal syntax. Open the literal on the same line as the assignment but do not include text on that line. Indent the text block one additional level.\n\n**Preferred**:\n\n```swift\nlet message = \"\"\"\n  You cannot charge the flux \\\n  capacitor with a 9V battery.\n  You must use a super-charger \\\n  which costs 10 credits. You currently \\\n  have \\(credits) credits available.\n  \"\"\"\n```\n\n**Not Preferred**:\n\n```swift\nlet message = \"\"\"You cannot charge the flux \\\n  capacitor with a 9V battery.\n  You must use a super-charger \\\n  which costs 10 credits. You currently \\\n  have \\(credits) credits available.\n  \"\"\"\n```\n\n**Not Preferred**:\n\n```swift\nlet message = \"You cannot charge the flux \" +\n  \"capacitor with a 9V battery.\\n\" +\n  \"You must use a super-charger \" +\n  \"which costs 10 credits. You currently \" +\n  \"have \\(credits) credits available.\"\n```\n\n## No Emoji\n\nDo not use emoji in your projects. For those readers who actually type in their code, it's an unnecessary source of friction. While it may be cute, it doesn't add to the learning and it interrupts the coding flow for these readers.\n\n## No #imageLiteral or #colorLiteral\n\nLikewise, do not use Xcode's ability to drag a color or an image into a source statement. These turn into #colorLiteral and #imageLiteral, respectively, and present unpleasant challenges for a reader trying to enter them based on tutorial text. Instead, use `UIColor(red:green:blue)` and `UIImage(imageLiteralResourceName:)`.\n\n## Organization and Bundle Identifier\n\nWhere an Xcode project is involved, the organization should be set to `Kodeco` and the Bundle Identifier set to `com.yourcompany.TutorialName` where `TutorialName` is the name of the tutorial project.\n\n![Xcode Project settings](screens/project_settings.png)\n\n## Copyright Statement\n\nThe following copyright statement should be included at the top of every source\nfile:\n\n```swift\n/// Copyright (c) 2023 Kodeco Inc.\n/// \n/// Permission is hereby granted, free of charge, to any person obtaining a copy\n/// of this software and associated documentation files (the \"Software\"), to deal\n/// in the Software without restriction, including without limitation the rights\n/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell\n/// copies of the Software, and to permit persons to whom the Software is\n/// furnished to do so, subject to the following conditions:\n/// \n/// The above copyright notice and this permission notice shall be included in\n/// all copies or substantial portions of the Software.\n/// \n/// Notwithstanding the foregoing, you may not use, copy, modify, merge, publish,\n/// distribute, sublicense, create a derivative work, and/or sell copies of the\n/// Software in any work that is designed, intended, or marketed for pedagogical or\n/// instructional purposes related to programming, coding, application development,\n/// or information technology.  Permission for such use, copying, modification,\n/// merger, publication, distribution, sublicensing, creation of derivative works,\n/// or sale is expressly withheld.\n/// \n/// This project and source code may use libraries or frameworks that are\n/// released under various Open-Source licenses. Use of those libraries and\n/// frameworks are governed by their own individual licenses.\n///\n/// THE SOFTWARE IS PROVIDED \"AS IS\", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR\n/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,\n/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE\n/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER\n/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,\n/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN\n/// THE SOFTWARE.\n```\n\n## Smiley Face\n\nSmiley faces are a very prominent style feature of the [Kodeco](https://www.kodeco.com/) site! It is very important to have the correct smile signifying the immense amount of happiness and excitement for the coding topic. The closing square bracket `]` is used because it represents the largest smile able to be captured using ASCII art. A closing parenthesis `)` creates a half-hearted smile, and thus is not preferred.\n\n**Preferred**:\n```\n:]\n```\n\n**Not Preferred**:\n```\n:)\n```\n\n## References\n\n* [The Swift API Design Guidelines](https://swift.org/documentation/api-design-guidelines/)\n* [The Swift Programming Language](https://developer.apple.com/library/prerelease/ios/documentation/swift/conceptual/swift_programming_language/index.html)\n* [Using Swift with Cocoa and Objective-C](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/BuildingCocoaApps/index.html)\n* [Swift Standard Library Reference](https://developer.apple.com/library/prerelease/ios/documentation/General/Reference/SwiftStandardLibraryReference/index.html)\n"
  },
  {
    "path": "SWIFTLINT.markdown",
    "content": "# The Official Kodeco SwiftLint Policy\n\nThe SwiftLint configuration in this repo is designed to ensure the work we create at Kodeco conforms with [The Official Kodeco Swift Style Guide](https://github.com/kodecocodes/swift-style-guide/blob/main/README.markdown).\n\nThe focus of this style is to improve readability in our print and web publications. Therefore, this style may be different from others you've used, but the demands of print and online reading are different from other contexts.\n\nThe policies described here have a goal of achieving consistency between all of our projects, which will also streamline the flow of content through our editing process. Some of the choices also aim to ensure we've removed as much of the burden from our readers as possible.\n\nThese guides use SwiftLint as a standard. You can learn more about SwiftLint by visiting its [official documentation page](https://github.com/realm/SwiftLint).\n\n## Table of Contents\n\n* [Installing SwiftLint](#installing-swiftlint)\n* [Using the Configuration File](#using-the-configuration-file)\n* [Xcode Settings](#xcode-settings)\n* [Running SwiftLint](#running-swiftlint)\n* [Handling Rule Exceptions](#handling-rule-exceptions)\n* [Approved Exceptions](#approved-exceptions)\n\t* [Implicitly Unwrapped Optionals](#implicitly-unwrapped-optionals)\n\t* [Force Cast](#force-cast)\n\t* [Force Unwrapping](#force-unwrapping)\n\t* [SwiftUI and Multiple Trailing Closures](#swiftui-and-multiple-trailing-closures)\n\t* [Open-Source Files](#open-source-files)\n* [Other Notes](#other-notes)\n\n## Installing SwiftLint\n\nWe recommend that Kodeco team members install SwiftLint using Homebrew:\n\n```bash\nbrew install swiftlint\n```\n\nIf you are unable to use Homebrew, you may use one of the other methods described in the [SwiftLint documentation](https://github.com/realm/SwiftLint).\n\n**Do not** install SwiftLint as a CocoaPod in your project.\n\n## Using the Configuration File\n\n**Do not** place the configuration file inside your project. We don't want to impose this style on readers without their express knowledge or understanding of what's going on. \n\nDownload **com.raywenderlich.swiftlint.yml** from the [Swift Style Guide repo]([https://github.com/raywenderlich/swift-style-guide](https://github.com/kodecocodes/swift-style-guide/)) and place it your home directory: **~/com.raywenderlich.swiftlint.yml**.\n\n## Xcode Settings\n\nYou'll need to configure Xcode to remove trailing whitespace from all lines. This is not the default configuration.\n\nIn Xcode's Preferences, select **Text Editing** ▸ **Editing** and check **Including whitespace-only lines**. \n\n![](screens/trailing-whitespace.png)\n\n## Running SwiftLint\n\nTo simplify the process for everyone in the content pipeline, you'll need to add the necessary instructions to your sample project to run SwiftLint automatically on each build. To do so:\n\n1. Select the project document in the Project navigator.\n1. Select the **Build Phases** tab.\n1. Click **+** and choose **New Run Script Phase**.\n\n![](screens/add-run-script.png)\n\n4. Drag the new phase before the **Compile Sources** phase.\n4. Click the disclosure triangle on the **Run Script** phase and ensure **Shell** is set to **/bin/sh**.\n\n![](screens/empty-run-script.png)\n\n6. Add the following script:\n```\nPATH=/opt/homebrew/bin:$PATH\nif [ -f ~/com.raywenderlich.swiftlint.yml ]; then\n  if which swiftlint >/dev/null; then\n    swiftlint --no-cache --config ~/com.raywenderlich.swiftlint.yml\n  fi\nfi\n```\n\n## Handling Rule Exceptions\n\nYour sample project must compile without warnings — SwiftLint or otherwise. In general, you should change your code to eliminate all warnings where necessary. When it comes to SwiftLint, however, there will be times when this isn't possible. In these situations, you'll need to use in-line comments to temporarily disable rules. You can find appropriate syntax to do this in [the SwiftLint documentation](https://realm.github.io/SwiftLint/#disable-rules-in-code).\n\nYou may only disable a rule if it is on the list of approved exceptions listed below.\n\nPrefer the form that disables a rule only for the next line:\n```\n// swiftlint:disable:next implicitly_unwrapped_optional\nvar injectedValue: Data!\n```\n\nOr, similarly, for the previous line:\n```\nvar injectedValue: Data!\n// swiftlint:disable:previous implicitly_unwrapped_optional\n```\n\nIf there are several approved exceptions, group them together and disable the rule for that region. Be sure to enable the rule after that section. Do not leave a rule disabled throughout the source file.\n\n```\n// swiftlint:disable implicitly_unwrapped_optional\nvar injectedValue1: Data!\nvar injectedValue2: Data!\n// swiftlint:enable implicitly_unwrapped_optional\n```\n\nIf you must disable rules in your project, leave those in-line comments in the project for the benefit of your teammates in the editing pipeline.\n\nFinally, if you're not sure which rule is triggering a warning, you can find the rule name in parentheses at the end of message:\n\n![](screens/swiftlint-warning.png)\n\n## Approved Exceptions\n\nThere are certain common idioms that violate SwiftLint's strict checking. If you are unable to work around them — and you've already tried to find a better way to structure your code — you may disable rules as described in this section.\n\nIf you find that you're struggling with rules other than those described below, please reach out to your Team Lead with your specific example.\n\n### Implicitly Unwrapped Optionals\n\nIt is sometimes common, in lieu of using dependency injection, to declare a child view controller's properties as Implicitly Unwrapped Optionals (IUO). If you're unable to structure your project to avoid this, you may disable the `implicitly_unwrapped_optional` rule for those dependency declarations. With the advent of `@IBSegueAction`, this should be rare.\n\n### Force Cast\n\nYou may use force casting — and disable the `force_cast` rule — in the `UITableViewDataSource` and `UICollectionViewDataSource` methods that dequeue cells.\n\n### Force Unwrapping\n\nYou may use forced unwrapping — rule name `force_unwrap` — when returning a color from an asset catalog:\n\n```\nstatic var rwGreen: UIColor {\n  // swiftlint:disable:next force_unwrapping\n  UIColor(named: \"rw-green\")!\n}\n```\n\nYou may also use it in the same context as the force cast exception above, dequeuing cells in `UITableViewDataSource` and `UICollectionViewDataSource` methods.\n\nAlthough we prefer you to model appropriately defensive code for our readers, you may use force unwrapping to access resources that you _know_ are included in the app bundle.\n\nFinally, you may use force unwrapping when constructing a `URL` from a hard-coded, and guaranteed valid, URL string.\n\n### SwiftUI and Multiple Trailing Closures\n\nIdiomatic SwiftUI uses trailing closures to provide the view content for certain user interface elements. `Button` is a prime example; it has an initializer form that uses a closure to provide its `label`. It's common to write something like the following:\n\n```\nButton(action: { self.isPresented.toggle() }) {\n  Image(systemName: \"plus\")\n}\n```\n\nThis violates the rule that you should not use trailing closure syntax when a method accepts multiple closure parameters, so SwiftLint will flag it with a warning. \n\nYou can work around this by extracting the `Button`'s action into a separate method. While this is frequently a better solution when the action requires several statements, it's an onerous requirement when the action is a single statement, as in the example above.\n\nIn these cases, you're permitted to disable this rule **for the declaration of a SwiftUI view** only. The rule name is `multiple_closures_with_trailing_closure`.\n\n### Open-Source Files\n\nOccasionally, you'll find it necessary to include an unmodified open-source file in the sample project. It's a virtual certainty that these files won't comply with our style guide. Our practice has always been to leave these files in their original state. In this situation, you should disable SwiftLint for the entire file:\n\n```\n// swiftlint:disable all\n```\n\n## Other Notes\n\nWhile SwiftLint goes a long way towards making your source code compliant with our style guide, it doesn't cover everything. For example, it won't catch or force you to correct the formatting for multi-condition `guard` statements. (See [Golden Path](https://github.com/raywenderlich/swift-style-guide#golden-path) for correct formatting.)\n\nThis configuration has been tested against several dozen of our most recent tutorials. A couple of rules, such as the line length limit or the limit on the length of a function, may need tweaking to fit our style. If you find yourself butting heads with SwiftLint, please reach out to the iOS Team Lead with details.\n"
  },
  {
    "path": "com.raywenderlich.swiftlint.yml",
    "content": "excluded:\n  - ${PWD}/Carthage\n  - ${PWD}/Pods\n  - ${PWD}/DerivedData\n\ndisabled_rules:\n  - discarded_notification_center_observer\n  - notification_center_detachment\n  - orphaned_doc_comment\n  - todo\n\nanalyzer_rules:\n  - unused_import\n\nopt_in_rules:\n  - array_init\n  - attributes\n  - closure_end_indentation\n  - closure_spacing\n  - collection_alignment\n  - colon # promote to error\n  - convenience_type\n  - discouraged_object_literal\n  - empty_collection_literal\n  - empty_count\n  - empty_string\n  - enum_case_associated_values_count\n  - fatal_error_message\n  - first_where\n  - force_unwrapping\n  - implicitly_unwrapped_optional\n  - indentation_width\n  - last_where\n  - legacy_random\n  - literal_expression_end_indentation\n  - multiline_arguments\n  - multiline_function_chains\n  - multiline_literal_brackets\n  - multiline_parameters\n  - multiline_parameters_brackets\n  - operator_usage_whitespace\n  - overridden_super_call\n  - pattern_matching_keywords\n  - prefer_self_type_over_type_of_self\n  - redundant_nil_coalescing\n  - redundant_type_annotation\n  - strict_fileprivate\n  - toggle_bool\n  - trailing_closure\n  - unneeded_parentheses_in_closure_argument\n  - vertical_whitespace_closing_braces\n  - vertical_whitespace_opening_braces\n  - yoda_condition\n\n\ncustom_rules:\n  array_constructor:\n    name: \"Array/Dictionary initializer\"\n    regex: '[let,var] .+ = (\\[.+\\]\\(\\))'\n    capture_group: 1\n    message: \"Use explicit type annotation when initializing empty arrays and dictionaries\"\n    severity: warning\n\n\nattributes:\n  always_on_same_line:\n    - \"@IBSegueAction\"\n    - \"@IBAction\"\n    - \"@NSManaged\"\n    - \"@objc\"\n\nforce_cast: warning\nforce_try: warning\nfunction_body_length:\n    warning: 60\n\nlegacy_hashing: error\n\nidentifier_name:\n  excluded:\n    - i\n    - id\n    - x\n    - y\n    - z\n\nindentation_width:\n  indentation_width: 2\n\nline_length:\n  ignores_urls: true\n  ignores_function_declarations: true\n  ignores_comments: true\n\nmultiline_arguments:\n  first_argument_location: next_line\n  only_enforce_after_first_closure_on_first_line: true\n  \nprivate_over_fileprivate:\n  validate_extensions: true\n\ntrailing_whitespace:\n  ignores_empty_lines: false\n  ignores_comments: true\n\nvertical_whitespace:\n  max_empty_lines: 2\n"
  }
]