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This 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.

Our overarching goals are clarity, consistency and brevity, in that order.

• Correctness
• Using SwiftLint
• Naming
  • Prose
  • Delegates
  • Use Type Inferred Context
  • Generics
  • Class Prefixes
  • Language
• Code Organization
  • Protocol Conformance
  • Unused Code
  • Minimal Imports
• Spacing
• Comments
• Classes and Structures
  • Use of Self
  • Protocol Conformance
  • Computed Properties
  • Final
• Function Declarations
• Function Calls
• Closure Expressions
• Types
  • Constants
  • Static Methods and Variable Type Properties
  • Optionals
  • Lazy Initialization
  • Type Inference
  • Syntactic Sugar
• Functions vs Methods
• Memory Management
  • Extending Object Lifetime
• Access Control
• Control Flow
  • Ternary Operator
• Golden Path
  • Failing Guards
• Semicolons
• Parentheses
• Multi-line String Literals
• No Emoji
• No #imageLiteral or #colorLiteral
• Organization and Bundle Identifier
• Copyright Statement
• Smiley Face
• References

Strive to make your code compile without warnings. This rule informs many style decisions such as using#selector types instead of string literals.

When writing for Kodeco, you are strongly encouraged — perhaps even required, depending on your team — to use our SwiftLint configuration. See theSwiftLint Policy for more information.

Descriptive and consistent naming makes software easier to read and understand. Use the Swift naming conventions described in theAPI Design Guidelines. Some key takeaways include:

• striving for clarity at the call site
• prioritizing clarity over brevity
• usingcamelCase (notsnake_case)
• usingUpperCamelCase for types and protocols,lowerCamelCase for everything else
• including all needed words while omitting needless words
• using names based on roles, not types
• sometimes compensating for weak type information
• striving for fluent usage
• beginning factory methods withmake
• naming methods for their side effects
  • verb methods follow the -ed, -ing rule for the non-mutating version
  • noun methods follow the formX rule for the mutating version
  • boolean types should read like assertions
  • protocols that describewhat something is should read as nouns
  • protocols that describea capability should end in-able or-ible
• using terms that don't surprise experts or confuse beginners
• generally avoiding abbreviations
• using precedent for names
• preferring methods and properties to free functions
• casing acronyms and initialisms uniformly up or down
• giving the same base name to methods that share the same meaning
• avoiding overloads on return type
• choosing good parameter names that serve as documentation
• preferring to name the first parameter instead of including its name in the method name, except as mentioned under Delegates
• labeling closure and tuple parameters
• taking advantage of default parameters

When referring to methods in prose, being unambiguous is critical. To refer to a method name, use the simplest form possible.

1. Write the method name with no parameters.Example: Next, you need to calladdTarget.
2. Write the method name with argument labels.Example: Next, you need to calladdTarget(_:action:).
3. Write the full method name with argument labels and types.Example: Next, you need to calladdTarget(_: Any?, action: Selector?).

For the above example usingUIGestureRecognizer, 1 is unambiguous and preferred.

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 pressShift-Control-Option-Command-C (all 4 modifier keys) and Xcode will kindly put the signature on your clipboard.

Swift 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.

import SomeModuleletmyClass=MyModule.UsefulClass()

When creating custom delegate methods, an unnamed first parameter should be the delegate source. (UIKit contains numerous examples of this.)

Preferred:

func namePickerView(_ namePickerView:NamePickerView, didSelectName name:String)func namePickerViewShouldReload(_ namePickerView:NamePickerView)->Bool

Not Preferred:

func didSelectName(namePicker:NamePickerViewController, name:String)func namePickerShouldReload()->Bool

Use compiler inferred context to write shorter, clear code. (Also seeType Inference.)

Preferred:

letselector= #selector(viewDidLoad)view.backgroundColor=.redlettoView= context.view(forKey:.to)letview=UIView(frame:.zero)

Not Preferred:

letselector= #selector(ViewController.viewDidLoad)view.backgroundColor=UIColor.redlettoView= context.view(forKey:UITransitionContextViewKey.to)letview=UIView(frame:CGRect.zero)

Generic 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 asT,U, orV.

Preferred:

structStack<Element>{...}func write<Target:OutputStream>(to target:inoutTarget)func swap<T>(_ a:inoutT, _ b:inoutT)

Not Preferred:

structStack<T>{...}func write<target:OutputStream>(to target:inouttarget)func swap<Thing>(_ a:inoutThing, _ b:inoutThing)

Use US English spelling to match Apple's API.

Preferred:

letcolor="red"

Not Preferred:

letcolour="red"

Use 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.

In 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.

Preferred:

classMyViewController:UIViewController{  // class stuff here}// MARK: - UITableViewDataSourceextensionMyViewController:UITableViewDataSource{  // table view data source methods}// MARK: - UIScrollViewDelegateextensionMyViewController:UIScrollViewDelegate{  // scroll view delegate methods}

Not Preferred:

classMyViewController:UIViewController,UITableViewDataSource,UIScrollViewDelegate{  // all methods}

Since 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.

For UIKit view controllers, consider grouping lifecycle, custom accessors, and IBAction in separate class extensions.

Unused (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.

Aspirational methods not directly associated with the tutorial whose implementation simply calls the superclass should also be removed. This includes any empty/unused UIApplicationDelegate methods.

Preferred:

overridefunc tableView(_ tableView:UITableView, numberOfRowsInSection section:Int)->Int{returnDatabase.contacts.count}

Not Preferred:

overridefunc didReceiveMemoryWarning(){  super.didReceiveMemoryWarning()  // Dispose of any resources that can be recreated.}overridefunc numberOfSections(in tableView:UITableView)->Int{  // #warning Incomplete implementation, return the number of sectionsreturn1}overridefunc tableView(_ tableView:UITableView, numberOfRowsInSection section:Int)->Int{  // #warning Incomplete implementation, return the number of rowsreturnDatabase.contacts.count}

Import only the modules a source file requires. For example, don't importUIKit when importingFoundation will suffice. Likewise, don't importFoundation if you must importUIKit.

Preferred:

import UIKitvarview:UIViewvardeviceModels:[String]

Preferred:

import FoundationvardeviceModels:[String]

Not Preferred:

import UIKitimport Foundationvarview:UIViewvardeviceModels:[String]

Not Preferred:

import UIKitvardeviceModels:[String]

• 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:

• 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.
• Tip: You can re-indent by selecting some code (orCommand-A to select all) and thenControl-I (orEditor ▸ 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.

Preferred:

if user.isHappy{  // Do something}else{  // Do something else}

Not Preferred:

if user.isHappy{  // Do something}else{  // Do something else}

• 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.

• There should be no blank lines after an opening brace or before a closing brace.

• Closing parentheses should not appear on a line by themselves.

Preferred:

letuser=tryawaitgetUser(  for: userID,  on: connection)

Not Preferred:

letuser=tryawaitgetUser(  for: userID,  on: connection)

• Colons always have no space on the left and one space on the right. Exceptions are the ternary operator? :, empty dictionary[:] and#selector syntaxaddTarget(_:action:).

Preferred:

classTestDatabase:Database{vardata:[String:CGFloat]=["A":1.2,"B":3.2]}

Not Preferred:

classTestDatabase:Database{vardata:[String:CGFloat]=["A":1.2,"B":3.2]}

• Long lines should be wrapped at around 70 characters. A hard limit is intentionally not specified.

• Avoid trailing whitespaces at the ends of lines.

• Add a single newline character at the end of each file.

When they are needed, use comments to explainwhy a particular piece of code does something. Comments must be kept up-to-date or deleted.

Avoid 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.

Avoid the use of C-style comments (/* ... */). Prefer the use of double- or triple-slash.

Remember, structs havevalue semantics. 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.

Classes havereference semantics. 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.

Sometimes, things should be structs but need to conform toAnyObject or are historically modeled as classes already (NSDate,NSSet). Try to follow these guidelines as closely as possible.

Here's an example of a well-styled class definition:

classCircle:Shape{varx:Int,y:Intvarradius:Doublevardiameter:Double{get{return radius*2}set{      radius= newValue/2}}init(x:Int, y:Int, radius:Double){self.x= xself.y= yself.radius= radius}convenienceinit(x:Int, y:Int, diameter:Double){self.init(x: x, y: y, radius: diameter/2)}overridefunc area()->Double{returnDouble.pi* radius* radius}}extensionCircle:CustomStringConvertible{vardescription:String{return"center =\(centerString) area =\(area())"}privatevarcenterString:String{return"(\(x),\(y))"}}

The example above demonstrates the following style guidelines:

• Specify types for properties, variables, constants, argument declarations and other statements with a space after the colon but not before, e.g.x: Int, andCircle: Shape.
• Define multiple variables and structures on a single line if they share a common purpose / context.
• Indent getter and setter definitions and property observers.
• Don't add modifiers such asinternal when they're already the default. Similarly, don't repeat the access modifier when overriding a method.
• Organize extra functionality (e.g. printing) in extensions.
• Hide non-shared, implementation details such ascenterString inside the extension usingprivate access control.

For conciseness, avoid usingself since Swift does not require it to access an object's properties or invoke its methods.

Use self only when required by the compiler (in@escaping closures, or in initializers to disambiguate properties from arguments). In other words, if it compiles withoutself then omit it.

For conciseness, if a computed property is read-only, omit the get clause. The get clause is required only when a set clause is provided.

Preferred:

vardiameter:Double{return radius*2}

Not Preferred:

vardiameter:Double{get{return radius*2}}

Marking classes or members asfinal in tutorials can distract from the main topic and is not required. Nevertheless, use offinal 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 itfinal makes that clear.

// Turn any generic type into a reference type using this Box class.finalclassBox<T>{letvalue:Tinit(_ value:T){self.value= value}}

Keep short function declarations on one line including the opening brace:

func reticulateSplines(spline:[Double])->Bool{  // reticulate code goes here}

For functions with long signatures, put each parameter on a new line and add an extra indent on subsequent lines:

func reticulateSplines(  spline:[Double],   adjustmentFactor:Double,  translateConstant:Int,   comment:String)->Bool{  // reticulate code goes here}

Don't use(Void) to represent the lack of an input; simply use(). UseVoid instead of() for closure and function outputs.

Preferred:

func updateConstraints()->Void{  // magic happens here}typealiasCompletionHandler=(result)->Void

Not Preferred:

func updateConstraints()->(){  // magic happens here}typealiasCompletionHandler=(result)->()

Mirror the style of function declarations at call sites. Calls that fit on a single line should be written as such:

letsuccess=reticulateSplines(splines)

If the call site must be wrapped, put each parameter on a new line, indented one additional level:

letsuccess=reticulateSplines(  spline: splines,  adjustmentFactor:1.3,  translateConstant:2,  comment:"normalize the display")

Use 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.

Preferred:

UIView.animate(withDuration:1.0){self.myView.alpha=0}UIView.animate(withDuration:1.0, animations:{self.myView.alpha=0}, completion:{ finishedinself.myView.removeFromSuperview()})

Not Preferred:

UIView.animate(withDuration:1.0, animations:{self.myView.alpha=0})UIView.animate(withDuration:1.0, animations:{self.myView.alpha=0}){ finself.myView.removeFromSuperview()}

For single-expression closures where the context is clear, use implicit returns:

attendeeList.sort{ a, bin  a> b}

Chained 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:

letvalue= numbers.map{ $0*2}.filter{ $0%3==0}.index(of:90)letvalue= numbers.map{$0*2}.filter{$0>50}.map{$0+10}

Always 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.

Preferred:

letwidth=120.0                                    // DoubleletwidthString="\(width)"                         // String

Less Preferred:

letwidth=120.0                                    // DoubleletwidthString=(widthasNSNumber).stringValue    // String

Not Preferred:

letwidth:NSNumber=120.0                          // NSNumberletwidthString:NSString= width.stringValue        // NSString

In drawing code, useCGFloat if it makes the code more succinct by avoiding too many conversions.

Constants are defined using thelet keyword and variables with thevar keyword. Always uselet instead ofvar if the value of the variable will not change.

Tip: A good technique is to define everything usinglet and only change it tovar if the compiler complains!

You 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 usestatic let. Type properties declared in this way are generally preferred over global constants because they are easier to distinguish from instance properties. Example:

Preferred:

enumMath{staticlete=2.718281828459045235360287staticletroot2=1.41421356237309504880168872}lethypotenuse= side* Math.root2

Note: The advantage of using a case-less enumeration is that it can't accidentally be instantiated and works as a pure namespace.

Not Preferred:

lete=2.718281828459045235360287  // pollutes global namespaceletroot2=1.41421356237309504880168872lethypotenuse= side* root2 // what is root2?

Static 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.

Declare variables and function return types as optional with? where anil value is acceptable.

Use 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 inviewDidLoad(). Prefer optional binding to implicitly unwrapped optionals in most other cases.

When accessing an optional value, use optional chaining if the value is only accessed once or if there are many optionals in the chain:

textContainer?.textLabel?.setNeedsDisplay()

Use optional binding when it's more convenient to unwrap once and perform multiple operations:

iflet textContainer= textContainer{  // do many things with textContainer}

Notes: Swift 5.7 introduced new shorthand syntax for unwrapping optionals into shadowed variables:

iflet textContainer{  // do many things with textContainer}

When naming optional variables and properties, avoid naming them likeoptionalString ormaybeView since their optional-ness is already in the type declaration.

For optional binding, shadow the original name whenever possible rather than using names likeunwrappedView oractualLabel.

Preferred:

varsubview:UIView?varvolume:Double?// later on...iflet subview= subview,let volume= volume{  // do something with unwrapped subview and volume}// another exampleresource.request().onComplete{[weak self] responseinguardlet self=selfelse{return}letmodel=self.updateModel(response)self.updateUI(model)}

Not Preferred:

varoptionalSubview:UIView?varvolume:Double?iflet unwrappedSubview= optionalSubview{iflet realVolume= volume{    // do something with unwrappedSubview and realVolume}}// another exampleUIView.animate(withDuration:2.0){[weak self]inguardlet strongSelf=selfelse{return}  strongSelf.alpha=1.0}

Consider using lazy initialization for finer grained control over object lifetime. This is especially true forUIViewController that loads views lazily. You can either use a closure that is immediately called{ }() or call a private factory method. Example:

lazyvarlocationManager=makeLocationManager()privatefunc makeLocationManager()->CLLocationManager{letmanager=CLLocationManager()  manager.desiredAccuracy= kCLLocationAccuracyBest  manager.delegate=self  manager.requestAlwaysAuthorization()return manager}

Notes:

• [unowned self] is not required here. A retain cycle is not created.
• Location manager has a side-effect for popping up UI to ask the user for permission so fine grain control makes sense here.

Prefer 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 asCGFloat orInt16.

Preferred:

letmessage="Click the button"letcurrentBounds=computeViewBounds()varnames=["Mic","Sam","Christine"]letmaximumWidth:CGFloat=106.5

Not Preferred:

letmessage:String="Click the button"letcurrentBounds:CGRect=computeViewBounds()varnames=[String]()

For empty arrays and dictionaries, use type annotation. (For an array or dictionary assigned to a large, multi-line literal, use type annotation.)

Preferred:

varnames:[String]=[]varlookup:[String:Int]=[:]

Not Preferred:

varnames=[String]()varlookup=[String: Int]()

NOTE: Following this guideline means picking descriptive names is even more important than before.

Prefer the shortcut versions of type declarations over the full generics syntax.

Preferred:

vardeviceModels:[String]varemployees:[Int:String]varfaxNumber:Int?

Not Preferred:

vardeviceModels:Array<String>varemployees:Dictionary<Int,String>varfaxNumber:Optional<Int>

Free 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.

Free functions are most appropriate when they aren't associated with any particular type or instance.

Preferred

letsorted= items.mergeSorted()  // easily discoverablerocket.launch()  // acts on the model

Not Preferred

letsorted=mergeSort(items)  // hard to discoverlaunch(&rocket)

Free Function Exceptions

lettuples=zip(a, b)  // feels natural as a free function (symmetry)letvalue=max(x, y, z)  // another free function that feels natural

Code (even non-production, tutorial demo code) should not create reference cycles. Analyze your object graph and prevent strong cycles withweak andunowned references. Alternatively, use value types (struct,enum) to prevent cycles altogether.

Extend object lifetime using the[weak self] andguard let self = self else { return } idiom.[weak self] is preferred to[unowned self] where it is not immediately obvious thatself outlives the closure. Explicitly extending lifetime is preferred to optional chaining.

Preferred

resource.request().onComplete{[weak self] responseinguardlet self=selfelse{return}letmodel=self.updateModel(response)self.updateUI(model)}

Not Preferred

// might crash if self is released before response returnsresource.request().onComplete{[unowned self] responseinletmodel=self.updateModel(response)self.updateUI(model)}

Not Preferred

// deallocate could happen between updating the model and updating UIresource.request().onComplete{[weak self] responseinletmodel=self?.updateModel(response)self?.updateUI(model)}

Full access control annotation in tutorials can distract from the main topic and is not required. Usingprivate andfileprivate appropriately, however, adds clarity and promotes encapsulation. Preferprivate tofileprivate; usefileprivate only when the compiler insists.

Only explicitly useopen,public, andinternal when you require a full access control specification.

Use access control as the leading property specifier. The only things that should come before access control are thestatic specifier or attributes such as@IBAction,@IBOutlet and@discardableResult.

Preferred:

privateletmessage="Great Scott!"classTimeMachine{privatedynamic lazyvarfluxCapacitor=FluxCapacitor()}

Not Preferred:

fileprivateletmessage="Great Scott!"classTimeMachine{    lazydynamicprivatevarfluxCapacitor=FluxCapacitor()}

Prefer thefor-in style offor loop over thewhile-condition-increment style.

Preferred:

for_in0..<3{print("Hello three times")}for(index, person)in attendeeList.enumerated(){print("\(person) is at position #\(index)")}forindexinstride(from:0, to: items.count, by:2){print(index)}forindexin(0...3).reversed(){print(index)}

Not Preferred:

vari=0while i<3{print("Hello three times")  i+=1}vari=0while i< attendeeList.count{letperson=attendeeList[i]print("\(person) is at position #\(i)")  i+=1}

The 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 anif 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.

Preferred:

letvalue=5result= value!=0? x: yletisHorizontal=trueresult= isHorizontal? x: y

Not Preferred:

result= a> b? x= c> d? c: d: y

When coding with conditionals, the left-hand margin of the code should be the "golden" or "happy" path. That is, don't nestif statements. Multiple return statements are OK. Theguard statement is built for this.

Preferred:

func computeFFT(context:Context?, inputData:InputData?)throws->Frequencies{guardlet context= contextelse{throwFFTError.noContext}guardlet inputData= inputDataelse{throwFFTError.noInputData}  // use context and input to compute the frequenciesreturn frequencies}

Not Preferred:

func computeFFT(context:Context?, inputData:InputData?)throws->Frequencies{iflet context= context{iflet inputData= inputData{      // use context and input to compute the frequenciesreturn frequencies}else{throwFFTError.noInputData}}else{throwFFTError.noContext}}

When multiple optionals are unwrapped either withguard orif let, minimize nesting by using the compound version when possible. In the compound version, place theguard on its own line, then indent each condition on its own line. Theelse clause is indented to match theguard itself, as shown below. Example:

Preferred:

guardlet number1= number1,let number2= number2,let number3= number3else{fatalError("impossible")}// do something with numbers

Not Preferred:

iflet number1= number1{iflet number2= number2{iflet number3= number3{      // do something with numbers}else{fatalError("impossible")}}else{fatalError("impossible")}}else{fatalError("impossible")}

Guard statements are required to exit in some way. Generally, this should be simple one line statement such asreturn,throw,break,continue, andfatalError(). Large code blocks should be avoided. If cleanup code is required for multiple exit points, consider using adefer block to avoid cleanup code duplication.

Swift 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.

Do not write multiple statements on a single line separated with semicolons.

Preferred:

letswift="not a scripting language"

Not Preferred:

letswift="not a scripting language";

NOTE: Swift is very different from JavaScript, where omitting semicolons isgenerally considered unsafe

Parentheses around conditionals are not required and should be omitted.

Preferred:

if name=="Hello"{print("World")}

Not Preferred:

if(name=="Hello"){print("World")}

In larger expressions, optional parentheses can sometimes make code read more clearly.

Preferred:

letplayerMark=(player== current?"X":"O")

When 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.

Preferred:

letmessage="""  You cannot charge the flux\  capacitor with a 9V battery.  You must use a super-charger\  which costs 10 credits. You currently\  have\(credits) credits available."""

Not Preferred:

letmessage="""You cannot charge the flux\  capacitor with a 9V battery.  You must use a super-charger\  which costs 10 credits. You currently\  have\(credits) credits available."""

Not Preferred:

letmessage="You cannot charge the flux"+"capacitor with a 9V battery.\n"+"You must use a super-charger"+"which costs 10 credits. You currently"+"have\(credits) credits available."

Do 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.

Likewise, 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, useUIColor(red:green:blue) andUIImage(imageLiteralResourceName:).

Where an Xcode project is involved, the organization should be set toKodeco and the Bundle Identifier set tocom.yourcompany.TutorialName whereTutorialName is the name of the tutorial project.

The following copyright statement should be included at the top of every sourcefile:

/// Copyright (c) 2023 Kodeco Inc./// /// Permission is hereby granted, free of charge, to any person obtaining a copy/// of this software and associated documentation files (the "Software"), to deal/// in the Software without restriction, including without limitation the rights/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell/// copies of the Software, and to permit persons to whom the Software is/// furnished to do so, subject to the following conditions:/// /// The above copyright notice and this permission notice shall be included in/// all copies or substantial portions of the Software./// /// Notwithstanding the foregoing, you may not use, copy, modify, merge, publish,/// distribute, sublicense, create a derivative work, and/or sell copies of the/// Software in any work that is designed, intended, or marketed for pedagogical or/// instructional purposes related to programming, coding, application development,/// or information technology.  Permission for such use, copying, modification,/// merger, publication, distribution, sublicensing, creation of derivative works,/// or sale is expressly withheld./// /// This project and source code may use libraries or frameworks that are/// released under various Open-Source licenses. Use of those libraries and/// frameworks are governed by their own individual licenses.////// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN/// THE SOFTWARE.

Smiley faces are a very prominent style feature of theKodeco 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.

Preferred:

:]

Not Preferred:

:)

• The Swift API Design Guidelines
• The Swift Programming Language
• Using Swift with Cocoa and Objective-C
• Swift Standard Library Reference