chriseidhof

protocol OptionalType {
    typealias T
    var optional: T? { get }
}

extension Optional : OptionalType {
    var optional: T? { return self }
}

extension SequenceType where Generator.Element: OptionalType {

duemunk

<img src="http://img.shields.io/badge/Operator_overload-guilty-red.svg" height="20" alt="Uses operator overloads"/>

rnapier

// This is pretty clean, but I often dislike chains of temporary variables
// They tend to lead to little bugs when you use the wrong one. Swift's warnings
// and 'let' reduce problems, though.
func pagesFromOpenSearchData(data: NSData) throws -> [Page] {
    let json = try NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions())

    guard      let array  = json as? [JSON]                 else { throw JSONError.BadArray(json) }
    guard case let value  = array[1] where array.count >= 2 else { throw JSONError.OutOfRange }
    guard      let titles = value as? [String]              else { throw JSONError.BadStringList(json) }

orta

post_install do |installer|
  app_plist = "Emergence/Info.plist"
  plist_buddy = "/usr/libexec/PlistBuddy"
  version = `#{plist_buddy} -c "Print CFBundleShortVersionString" #{app_plist}`.split
  puts "Updating CocoaPods' version numbers to #{version}"

  installer.pods_project.targets.each do |target|
    `#{plist_buddy} -c "Set CFBundleShortVersionString #{version}" "Pods/Target Support Files/#{target}/Info.plist"`
  end
end

krzysztofzablocki

// swiftlint:disable file_length

fileprivate func compareOptionals<T>(lhs: T?, rhs: T?, compare: (_ lhs: T, _ rhs: T) -> Bool) -> Bool {
    switch (lhs, rhs) {
    case let (lValue?, rValue?):
        return compare(lValue, rValue)
    case (nil, nil):
        return true
    default:
        return false

odrobnik

import Foundation

public class UploadProgress: NSProgress
{
    var sessionTask: NSURLSessionTask!
    
    required public init(sessionTask: NSURLSessionTask)
    {
        super.init(parent: nil, userInfo: nil)
        

andymatuschak

struct User {
	let id: Int
	let name: String
	let email: String?
}

extension User: JSONDecodable {
	static func create(id: Int, name: String, email: String?) -> User {
		return User(id: id, name: name, email: email)
	}

chriseidhof

import Cocoa

struct Person {
    var name: String = "John"
    var age: Int = 50
    var dutch: Bool = false
    var address: Address? = Address(street: "Market St.")
}

struct Address {

gist:8a163db3f7f3d81d5296

Your goals are to reduce the number of things that you have to keep in your head at any given moment, and to rely as little as possible on your own ability to consistently do things right.
If you make a thing immutable ('let' in swift), you never have to think about what happens if it changes, or what other parts of the code you'll effect if you change it.
If you split complex functions into several smaller functions that only interact by passing arguments or getting return values, then you limit the amount of code you need to consider when hunting for a bug, and you can test each small piece separately.
If you understand what things must be true in your code (aka invariants, for example "a person's age must be greater than 0"), and either provide no function that can cause them to be untrue, or check and crash immediately when they're untrue, then you don't have to debug issues caused by incorrect assumptions.
If you remove possibilities (for example, Swift removes the possibility of things being nil unless 

cabeca

#!/usr/bin/env ruby

device_types_output = `xcrun simctl list devicetypes`
device_types = device_types_output.scan /(.*) \((.*)\)/

runtimes_output = `xcrun simctl list runtimes`
runtimes = runtimes_output.scan /(.*) \(.*\) \((com.apple[^)]+)\)$/

devices_output = `xcrun simctl list devices`
devices = devices_output.scan /\s\s\s\s(.*) \(([^)]+)\) (.*)/