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// macros that can be used to quickly check the model of current iPhone in your Objective-C code. 
#define IS_IPHONE_6_PLUS ( fabs( ( double )[ [ UIScreen mainScreen ] bounds ].size.height - ( double )736 ) < DBL_EPSILON )
#define IS_IPHONE_6      ( fabs( ( double )[ [ UIScreen mainScreen ] bounds ].size.height - ( double )667 ) < DBL_EPSILON )
#define IS_IPHONE_5      ( fabs( ( double )[ [ UIScreen mainScreen ] bounds ].size.height - ( double )568 ) < DBL_EPSILON )
#define IS_IPHONE_4      ( fabs( ( double )[ [ UIScreen mainScreen ] bounds ].size.height - ( double )480 ) < DBL_EPSILON )

lizixroy

/* Let's explore a little bit how to break the strong reference cycles. 
 * In this Playground file I re-created the examples mentioned in the ARC chapter in the Swift Porgramming Lang book: https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/AutomaticReferenceCounting.html
 * In each section, the code is implemented to avoid strong reference cycle. If you want to see how a strong reference cycle can actually occur follow the comments in each section play for yourself.
 * Avoiding memory leak is important for making your app memory-efficient and, in some cases, removing the risks of crashing out.
 */

import UIKit

/* Section 1 */

lizixroy

class Language {
	private let separator = ", "
	private var productions = [String: [String]]()
	
	init(setUpProductionRules: Bool) {
		if setUpProductionRules {
			self.setUpProductionRules()		
		}
	}
	

lizixroy

class ParseTreeNode {
	let nonTerminal: String
	let leftNode: ParseTreeNode?
	let rightNode: ParseTreeNode?	
	init(nonTerminal: String, leftNode: ParseTreeNode?, rightNode: ParseTreeNode?) {
		self.nonTerminal = nonTerminal
		self.leftNode = leftNode
		self.rightNode = rightNode
	}
}

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class CKYParser {
	func parse(words words: [String], language: Language) -> [[[ParseTreeNode]]] {
		let wordCount = words.count
		var table = [[[ParseTreeNode]]]()
		for _ in 0...words.count - 1 {
			let array = [[ParseTreeNode]](count: wordCount, repeatedValue: [ParseTreeNode]())
			table.append(array)
		}
		// populate lexicon. assuming all the words are in our lexicon
		for index in 0...words.count - 1 {

lizixroy

let wordCount = words.count
var table = [[[ParseTreeNode]]]()
for _ in 0...words.count - 1 {
  let array = [[ParseTreeNode]](count: wordCount, repeatedValue: [ParseTreeNode]())
  table.append(array)
}

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for index in 0...words.count - 1 {
  let word = words[index]
  let nonTerminals = language.recognize([word])!
  for nonTerminal in nonTerminals {
    table[index][index].append(ParseTreeNode(nonTerminal: nonTerminal, leftNode: nil, rightNode: nil))
  }
}

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for col in 0...wordCount - 1 {
	for row in (0...wordCount - 1).reverse() {
		var t = row
		while t + 1 <= col {
			let arr1 = table[row][t]
			let arr2 = table[t + 1][col]
			if arr1.count == 0 || arr2.count == 0 {
				t += 1
				continue
			}

lizixroy

class MessageViewModel {
    let messageSubject = BehaviorSubject<String>(value: "Greetings")
    
    func receiveMessage(message: String) {
        messageSubject.onNext(message)
    }
}

class MessageViewController: UIViewController {
    

lizixroy

messageViewModel.messageSubject.subscribeNext { [unowned self] message in
  self.messageLabel.text = message
}.addDisposableTo(disposeBag)