This style guide means to address the proper spacing in a Swift file to achieve maximum readability. It may change over time and pull requests and comments are greatly apreciated.
If you "like to see as much of your code as possible and you think adding unnecessary extra white lines goes against this", maybe you need a larger display or maybe you should consider refactoring your files into smaller chuncks.
Files should contain no headers. Any license text should be added on your project's LICENSE.md file or README.txt or similar, but not in each individual file. Autogenerated headers should not be included.
Avoid starting your files with things like:
//
// Created by John Smith on 6/5/16.
// Copyright (c) 2016 Smithy, Inc. All rights reserved.
//
Typically the very first line of a file should be an import.
import Foundation
Files should end with an empty line.
protocol MediaType {
[code]
}
Each import should occupy a new line. After all imports are declared, a blank line should be added before the entity declaration.
import Foundation
import MapKit
class SmithyMapViewController {
[code]
A file may define multiple entities. One blank line of separation should be added between them.
enum MyEnum {
[code]
}
class MyClass {
[code]
}
extension MyClass {
[code]
}
All blocks of code, in general should be treated the same. A block of code is delimited by { and }. A few rules apply to this.
Blocks always open in the same line as the code that's declaring this block. Afterwards, a blank line should always be added.
class MyView: UIView {
[code]
}
or
while total >= maximum {
[code]
}
or
myView.keepAnimatedWithDuration(interval) {
[code]
}
Blocks close right after the last line of code of the block and leave a blank line to the next line of code, except it's a nested block and whose parent block needs to close as well.
Single close:
[code]
}
[code]
Nested close:
[code]
}
}
[code]
There are some flow control expressions that serve as connector for two blocks of code. In this case, both the opening and closing share the same line. A blank line of code should be added previous to this expressions, and like with every other opening, an extra line should be added afterwards.
Some examples:
[code]
} else if x > width {
[code]
[code]
} else {
[code]
[code]
} catch MyError.InvalidSelection {
[code]
Closures chaining is a special case of blocks of code. When chaining, consecutive closures invokations should start on a new line along with the . accessor.
array.map {
[code]
}
.filter {
[code]
}
.reduce("") {
[code]
}
[code]
The switch statement is special because it doesn't use curly braces to define the blocks of code that should be executed in each case. Indent cases in the same level as switch and use a blank line after every option and an extra blank line after it, unless it's the final option.
Like this:
switch compassPoint {
case .North:
[code]
case .South:
[code]
default:
[code]
}
[code]
The returned object from a func or closure is typically important. Separate it from the rest of the code with a blank line.
func formattedAddress(street: String, city: String?, zipCode: String?, country: String) {
var formattedAddress = ""
[code]
return formattedAddress
}
For inline comments, a blank space should be added after the end of the code. For full line comments a blank line should be added before it. Both should have a space between the // and the comment itself.
In line:
print(name) // Prints the name of the user in the console.
Full line:
[code]
// We are safe to mark this as done since it's asigned to the current user.
if task.assignee == currentUser {
[code]
}
Blank lines can be used to separate different sections of code to create logical groups. A single line of separation should be enough.
SDK vs. 3rd parties imports:
import Foundation
import UIKit
import MapKit
import CoreLocation
import ReactiveCocoa
import EasyPeasy
Properties type and scope:
static let LegalDrinkingAge = 18
let name: String
let age: Int
private let apiClient: MyApiClient
private let credentialsStorage: MyCredentialsStorage
Initialization and configuration of different objects:
let firstNameLabel = UILabel()
firstNameLabel.text = "First Name"
let lastNameLabel = UILabel()
lastNameLabel.text = "Last Name"
Initializing variables versus doing something with them:
init(withConfig: ConfigStore, client: MyApiClient) {
self.config = config
self.client = client
self.setupBindings()
}