407 swift interoperability in depth

8/10/2019 407 Swift Interoperability in Depth

1/173

2014 Apple Inc. All rights reserved. Redistribution or public display not permitted without written permission from Apple.

#WWD

Swift Interoperability in Depth

Session 407Doug GregorEngineer, Swift Compiler Team

Tools


2/173

Introduction

Swift is a new language for Cocoa

Seamless interoperability with Objective-C

Focus on language-level interoperability


3/173

Roadmap

Working with Cocoa How Objective-C APIs look and feel in Swift

id and AnyObject

Bridging Core Cocoa Types

Subclassing Objective-C ClassesCF Interoperability


4/173

Working with Cocoa


5/173

Swift View of Objective-C APIs

Swift provides seamless access to Objective-C APIs


6/173



Swift view of an Objective-C API is different from Objective-C


7/173



Swift view of an Objective-C API is different from Objective-C

Same Cocoa conventions and idioms


8/173


9/173

Properties

Objective-C@property NSDate *fileModificationDate;


10/173

Properties

Objective-C@property NSDate *fileModificationDate;

Swiftvar fileModificationDate: NSDate!


11/173

Implicitly Unwrapped Optionals

var fileModificationDate: NSDate !


12/173



A value of class type in Swift is never nil


13/173




Optional types generalize the notion of nil


14/173




Optional types generalize the notion of nil

Objective-C does not have a notion of a never- nil pointer


15/173


16/173

Objective-C@property (readonly) NSString *fileType;

Mapping Objective-C Types to Swift


17/173

Objective-C@property (readonly) NSString *fileType;

Swiftvar fileType: String ! { get }

Mapping Objective-C Types to Swift


18/173

Objective-C Types in Swift


19/173

Objective-C- (NSString *)fileNameExtensionForType:(NSString *)typeName

saveOperation:(UIDocumentSaveOperation)saveOperation;

Methods


20/173

Objective-C- (NSString *)fileNameExtensionForType:(NSString *)typeName

saveOperation:(UIDocumentSaveOperation)saveOperation;

Swiftfunc fileNameExtensionForType(typeName: String!,

saveOperation: UIDocumentSaveOperation) -> String!

Methods


21/173


22/173


23/173

Objective-C- (void)saveToURL:(NSURL *)url

forSaveOperation:(UIDocumentSaveOperation)saveOperationcompletionHandler:(void (^)(BOOL success))completionHandler;

Methods


24/173


forSaveOperation:(UIDocumentSaveOperation)saveOperationcompletionHandler:(void (^)(BOOL success))completionHandler;

Swiftfunc saveToURL(url: NSURL!,

forSaveOperation saveOperation: UIDocumentSaveOperation, completionHandler: ((success: Bool) -> Void)!)

Methods


25/173


26/173

MethodsArgument labels and internal parameter names


forSaveOperation :(UIDocumentSaveOperation) saveOperation completionHandler:(void (^)(BOOL success))completionHandler;


forSaveOperation saveOperation : UIDocumentSaveOperation, completionHandler: ((success: Bool) -> Void)!)


27/173


forSaveOperation:(UIDocumentSaveOperation)saveOperationcompletionHandler:( void (^)(BOOL success) )completionHandler;

Swiftfunc saveToURL(url: NSURL!,forSaveOperation saveOperation: UIDocumentSaveOperation,

completionHandler: ((success: Bool) -> Void)! )

Blocks and closuresMethods


28/173



Methods


29/173



Trailing closure syntaxMethods

h d


30/173



Usage document.saveToURL(documentURL, saveOperation: UIDocumentSaveOperation.ForCreating) {

success inif success { } else { }

}

Trailing closure syntaxMethods

I i i li


31/173

Initializers

Objective-C- (instancetype)initWithFileURL:(NSURL *)url;

I i i li


32/173

Initializers


Swiftinit(fileURL url: NSURL!)

I i i li


33/173

Initializers



I iti li


34/173

Initializers



I iti li


35/173

Initializers

Objective-C- (instancetype)initWith FileURL :(NSURL *)url;

Swiftinit( fileURL url: NSURL!)

Creating Objects


36/173

Creating Objects


UIDocument *document = [[UIDocument alloc ] initWithFileURL :documentURL];

Creating Objects


37/173

Creating Objects



UIDocument *document = [[UIDocument alloc ] initWithFileURL :documentURL];

let document = UIDocument ( fileURL : documentURL)

Factory Methods


38/173

Factory Methods

Objective-C+ (UIColor *)colorWithRed:(CGFloat)red green:(CGFloat)green

blue:(CGFloat)blue alpha:(CGFloat)alpha;

Factory Methods


39/173

Factory Methods


blue:(CGFloat)blue alpha:(CGFloat)alpha; UIColor *color = [ UIColor colorWithRed :1 green :0.67 blue :0.04 alpha :0];

Factory Methods


40/173

Factory Methods



Swiftclass func colorWithRed(red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat) -> UIColor!

UIColor *color = [ UIColor colorWithRed :1 green :0.67 blue :0.04 alpha :0];

Factory Methods


41/173

Factory Methods



Swiftclass func colorWithRed(red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat) -> UIColor!

let color = UIColor.colorWithRed (1, green : 0.67, blue : 0.04, alpha : 0)

UIColor *color = [ UIColor colorWithRed :1 green :0.67 blue :0.04 alpha :0];

Factory Methods as Initializers


42/173




Swift

UIColor *color = [UIColor colorWithRed:1 green:0.67 blue:0.04 alpha:0];

init ( red : CGFloat, green : CGFloat, blue : CGFloat, alpha : CGFloat)



43/173




Swift

let color = UIColor ( red : 1, green : 0.67, blue : 0.04, alpha : 0)

UIColor *color = [UIColor colorWithRed:1 green:0.67 blue:0.04 alpha:0];

init ( red : CGFloat, green : CGFloat, blue : CGFloat, alpha : CGFloat)

Enums


44/173

Enums

Objective-Ctypedef NS_ENUM(NSInteger, UIDocumentSaveOperation) { UIDocumentSaveForCreating, UIDocumentSaveForOverwriting};

Enums


45/173

Enums

Objective-Ctypedef NS_ENUM(NSInteger, UIDocumentSave Operation) { UIDocumentSave ForCreating, UIDocumentSave ForOverwriting};

Enums


46/173

Enums

Objective-Ctypedef NS_ENUM(NSInteger, UIDocumentSaveOperation) { UIDocumentSaveForCreating, UIDocumentSaveForOverwriting};

Swiftenum UIDocumentSaveOperation : Int { case ForCreating case ForOverwriting}


47/173

Usage let ext = document.fileNameExtensionForType("public.presentation",

saveOperation:


Using Enums


48/173

Usage let ext = document.fileNameExtensionForType("public.presentation",

saveOperation:

Using Enums

.ForCreating)UIDocumentSaveOperation



49/173

NSError


50/173

Objective-C- (id)contentsForType:(NSString *)typeName error:( NSError ** )outError;

S o

NSError


51/173

Objective-C- (id)contentsForType:(NSString *)typeName error:( NSError ** )outError;

Swiftfunc contentsForType(typeName: String!, error: NSErrorPointer ) -> AnyObject!


52/173

Using NSError


53/173

g

Swiftfunc contentsForType(typeName: String!, error: NSErrorPointer) -> AnyObject!

Using NSError


54/173

g

Swiftfunc contentsForType(typeName: String!, error: NSErrorPointer) -> AnyObject!

Usage var error: NSError? if let contents = document.contentsForType("public.presentation",

error: &error ) {

// use the contents

}


55/173


56/173

Modernizing Your Objective-C


57/173

These rules apply to all Objective-C APIs imported into SwiftSwift benefits greatly from modern Objective-C:

Properties

instancetype

NS_ENUM / NS_OPTIONS

NS_DESIGNATED_INITIALIZER



58/173


Properties

instancetype





59/173


Properties

instancetype




60/173

id and AnyObject

id in Objective-C


61/173

Upcasts

id object = [[NSURL alloc] initWithString:@" http://developer.apple.com "]; object = view.superview;

id in Objective-C


62/173

Upcasts


Message sends [object removeFromSuperview];

id in Objective-C


63/173

Upcasts



Subscriptingid date = object[@"date"];

AnyObject: An Object of Any Type


64/173

Upcasts






65/173

Upcasts

var object: AnyObject = NSURL(string: " http://developer.apple.com ") object = view.superview





66/173

Upcasts


Message sends object.removeFromSuperview()




67/173

Upcasts


Message sends object.removeFromSuperview()

Subscriptinglet date = object["date"]


68/173

respondsToSelector Idiom


69/173

Messaging id or AnyObject can result in unrecognized selector failures

[object removeFromSuperview];

respondsToSelector idiom to test the presence of a method if ([object respondsToSelector :@selector(removeFromSuperview)]) {

[object removeFromSuperview];}

Checking the Presence of a Method


70/173

A method of AnyObject is optionalobject.removeFromSuperview ()

Checking the Presence of a Method


71/173

A method of AnyObject is optionalobject.removeFromSuperview

Chaining ? folds the respondsToSelector check into the call

?()


72/173

Downcasting AnyObject


73/173

AnyObject does not implicitly downcastlet view: UIView = object // error : AnyObject cannot be implicitly downcast



74/173

AnyObject does not implicitly downcastlet view: UIView = object

as operator forces the downcastlet view

// error : AnyObject cannot be implicitly downcast

= object as UIView



75/173

AnyObject does not implicitly downcastlet view: UIView = object

as operator forces the downcastlet view

as? operator performs a conditional downcastif let view = object as? UIView { // view is a UIView }

// error : AnyObject cannot be implicitly downcast

= object as UIView

Protocols


76/173

Objective-C@protocol UITableViewDataSource@optional- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView;@required- (NSInteger)tableView:(UITableView *)tableView

numberOfRowsInSection:(NSInteger)section;@end

Protocols


77/173



Swift@objc protocol UITableViewDataSource : NSObjectProtocol { func tableView(tableView: UITableView, numberOfRowsInSection: Int) -> Int @optional func numberOfSectionsInTableView(tableView: UITableView) -> Int}

Protocols


78/173



Swift@objc protocol UITableViewDataSource : NSObjectProtocol { func tableView(tableView: UITableView, numberOfRowsInSection: Int) -> Int @optional func numberOfSectionsInTableView(tableView: UITableView) -> Int}

Protocols


79/173

Objective-C@protocol UITableViewDataSource< NSObject >@optional- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView;@required- (NSInteger)tableView:(UITableView *)tableView


Swift@objc protocol UITableViewDataSource : NSObjectProtocol {

func tableView(tableView: UITableView, numberOfRowsInSection: Int) -> Int @optional func numberOfSectionsInTableView(tableView: UITableView) -> Int}

Protocol Types


80/173

Objective-C@property id dataSource;

Protocol Types


81/173


Swiftvar dataSource: UITableViewDataSource !

Testing Protocol Conformance


82/173

Downcast via as? to protocol type if let dataSource = object as? UITableViewDataSource { let rowsInFirstSection = dataSource.tableView(tableView, numberOfRowsInSection: 0)}

Protocol Types


83/173


Swiftvar dataSource: UITableViewDataSource!

@property id delegate;

var delegate: protocol

Number of Rows in the Last Section


84/173

if let dataSource = object as? UITableViewDataSource {var lastSection = 0

let rowsInLastSection = dataSource.tableView(tableView, numberOfRowsInSection: lastSection)

}

let numSections = dataSource.numberOfSectionsInTableViewlastSection = numSections - 1

(tableView)

Optional Methods in Protocols


85/173



}


(tableView)



86/173



}


(tableView)// error : method is optional



87/173

Use the chaining ? operatorif let dataSource = object as? UITableViewDataSource {

var lastSection = 0


}


(tableView)



88/173


var lastSection = 0


}

let numSections = dataSource.numberOfSectionsInTableView if

}lastSection = numSections - 1

(tableView)?



89/173


var lastSection = 0


}

let numSections = dataSource.numberOfSectionsInTableView if

}lastSection = numSections - 1

(tableView)?

Optionals and Safety


90/173



91/173

AnyObject is Swifts equivalent to id Similar functionality, more safe by default AnyClass is Swifts equivalent to Class



92/173

AnyObject is Swifts equivalent to id Similar functionality, more safe by default AnyClass is Swifts equivalent to Class

Optionals used throughout the language to represent dynamic checks as? for safe downcasting, protocol conformance checking

Optionals when referring to methods that may not be available if let and chaining ? make optionals easy to use


93/173

Bridging Core Cocoa Types

Native Strings, Arrays, Dictionaries


94/173

One set of general-purpose native value types Safe by default

Predictable performance

Typed collections support items of any type

Bridged to Cocoa NSString , NSArray , NSDictionary

Native String Type


95/173

String is an efficient, Unicode-compliant string type

Flexible, efficient, high-level APIs for string manipulation

Value semantics

Native String Type


96/173

String is an efficient, Unicode-compliant string type

Flexible, efficient, high-level APIs for string manipulation

Value semanticsvar s1 = "Hello"var s2 = s1s1 += " Swiftprintln(s1)Hello Swiftprintln(s2)Hello

Characters


97/173

Iteration over a string produces characters let dog = "Dog! ! "for c in dog { // c is inferred as Character println(c)}

Characters


98/173

Iteration over a string produces characters let dog = "Dog! ! "for c in dog { // c is inferred as Character println(c)}

Dog! !

Characters and Code Points


99/173

Unicode characters cannot be efficiently encoded as fixed-width entities



100/173

Unicode characters cannot be efficiently encoded as fixed-width entities Correct use of UTF-8 or UTF-16 requires deep knowledge of Unicode



101/173


Low-level operations ( length , characterAtIndex ) are not provided by String



102/173



countElements can be used to count the number of characters let dog = "Dog! ! "

println("There are \( countElements(dog) ) characters in `\(dog)")



103/173



countElements can be used to count the number of characters let dog = "Dog! ! "

println("There are \( countElements(dog) ) characters in `\(dog)")

// There are 5 characters in `Dog! !

Code Points


104/173

UTF-16 is available via a property

for codePoint in dog.utf16 { // codePoint is inferred as UInt16 // } print("There are \( countElements(dog.utf16) ) UTF-16 code points in `\(dog)")

Code Points


105/173

UTF-16 is available via a property

for codePoint in dog.utf16 { // codePoint is inferred as UInt16 // } print("There are \( countElements(dog.utf16) ) UTF-16 code points in `\(dog)")

// There are 6 UTF-16 code points in `Dog! !

String and NSString


106/173

Foundation NSString APIs are available on Stringlet fruits = "apple;banana;cherry".componentsSeparatedByString(";")

String and NSString


107/173


// inferred as String[]

String and NSString


108/173


Cast to NSString to access properties and methods on NSString categories ("Welcome to WWDC 2014" as NSString ).myNSStringMethod()


String and NSString


109/173


Cast to NSString to access properties and methods on NSString categories ("Welcome to WWDC 2014" as NSString ).myNSStringMethod()

Extend String with your method

extension String { func myStringMethod() -> String { }

}


NSArray Bridges to Array of AnyObject


110/173

Objective-C@property NSArray *toolbarItems;

NSArray Bridges to Array of AnyObject


111/173

Objective-C@property NSArray *toolbarItems;

Swiftvar toolbarItems: AnyObject[] !

Upcasting Arrays


112/173

An array T[] can be assigned to an AnyObject[]let myToolbarItems: UIBarButtonItem[] = [item1, item2, item3]controller.toolbarItems = myToolbarItems

Downcasting Arrays


113/173

Iteration over an AnyObject[] produces AnyObject values for object: AnyObject in viewController.toolbarItems { let item = object as UIBarButtonItem // }

Downcasting Arrays


114/173

Iteration over an AnyObject[] produces AnyObject values for object: AnyObject in viewController.toolbarItems { let item = object as UIBarButtonItem // }

Can downcast AnyObject[] to an array of a specific type for item in viewController.toolbarItems as UIBarButtonItem[] {

// }

Array BridgingUnder the Hood


115/173

Swift array has two representations

T[]



116/173


Native0 1 2 3 4 5length capacity 6

T[]



117/173


NSArray object

Native

Cocoa

0 1 2 3 4 5length capacity 6

T[]



118/173


Array methods manage the representation internally

NSArray object

Native

Cocoa


T[]



119/173


Array methods manage the representation internally

Bridging converts between NSArray and a Swift array

NSArray object

Native

Cocoa


T[]

NSArray Swift Array Bridging"


120/173

Returning an NSArray * from an Objective-C method to Swiftlet items: AnyObject[] = viewController.toolbarItems



121/173


NSArray object

Native

Cocoa


T[]



122/173


Calls copy() to ensure the array wont change underneath us

NSArray object

Native

Cocoa


T[]

NSArray Swift Array Bridging

*

"


123/173


Calls copy() to ensure the array wont change underneath us For immutable NSArray s, this operation is trivial

NSArray object

Native

Cocoa


T[]

P i S if Obj i C h d i SA *

T[] NSArray Bridging"


124/173

Passing a Swift array to an Objective-C method expecting an NSArray *viewController.toolbarItems = myToolbarItems

P i T[] Obj i C h d i NSA *



125/173

isa

Passing a T[] to an Objective-C method expecting an NSArray*

viewController.toolbarItems = myToolbarItems

NSArray object

Native

Cocoa

T[]


P i T[] t Obj ti C th d ti NSA *



126/173

isa

Passing a T[] to an Objective-C method expecting an NSArray*

viewController.toolbarItems = myToolbarItems

Native array representation isa NSArray, optimized

NSArray object

Native

Cocoa

T[]



127/173

Subclassing Objective-C Classes

Swift Objects Are Objective-C Objects

All Swift classes are id compatible


128/173


Same layout as an Objective-C class Same basic infrastructure (retain/release/class/etc.)

Swift Objects Are Objective-C Objects



129/173


Same layout as an Objective-C class Same basic infrastructure (retain/release/class/etc.)

Inherit from an Objective-C class to make your class directly visible in Objective-Cclass MyDocument : UIDocument { var items: String[] = []}

Overriding Methods

overridekeyword required when overriding a method


130/173

override keyword required when overriding a method

override func handleError(error: NSError!, userInteractionPermitted: Bool) { // customized behavior super.handleError(error,

userInteractionPermitted: userInteractionPermitted)}

Overriding Properties

Override the property itself, not the getter or setter


131/173

Override the property itself, not the getter or setter

override var description: String {return "MyDocument containing \(items)"

}


132/173

Swift

Your Swift Class


133/173

class MyDocument : UIDocument { var items: String[] = []

override func handleError(error: NSError, userInteractionPermitted: Bool)

override var description: String

override func contentsForType(typeName: String!, error: NSErrorPointer)-> AnyObject!

}

Objective-C

Your Swift Classin Objective-C


134/173

j

SWIFT_CLASS("_TtC5MyApp10MyDocument")@interface MyDocument : UIDocument @property (nonatomic) NSArray *items; - (void)handleError:(NSError *)error

userInteractionPermitted:(BOOL)userInteractionPermitted;

@property (nonatomic, readonly) NSString *description; - (id)contentsForType:(NSString *)typeName error:(NSError **)outError;@end


135/173

Objective-C



136/173

SWIFT_CLASS("_TtC5MyApp10MyDocument")@interface MyDocument : UIDocument @property (nonatomic) NSArray *items; - (void)handleError:(NSError *)error



// Swift:var items: String[] = []

Objective-C



137/173

SWIFT_CLASS(" _TtC5MyApp10MyDocument ") @interface MyDocument : UIDocument @property (nonatomic) NSArray *items; - (void)handleError:(NSError *)error



Objective-C



138/173

SWIFT_CLASS(" _TtC5MyApp10MyDocument ") @interface MyDocument : UIDocument @property (nonatomic) NSArray *items; - (void)handleError:(NSError *)error



// usually written MyApp.MyDocume

Limitations of Objective-C

Swift has advanced features that arent expressible in Objective-C


139/173

Tuples

Generics Enums and structs

func myGenericMethod(x: T) -> (String, String) { }

Limitations of Objective-C

Swift has advanced features that arent expressible in Objective-C


140/173

Tuples

Generics Enums and structs

objc attribute verifies that the declaration can be used in Objective-C

func myGenericMethod(x: T) -> (String, String) { }@objc// error: not expressible in Objective-C

Controlling Objective-C Names

objc attribute can be used to change the name of an Objective-C method bl d B l {


141/173

var enabled: Bool {

set { }}

get { }


objc attribute can be used to change the name of an Objective-C method bl d B l { // t i d bl d


142/173

var enabled: Bool {

set { }}

// property is named enabled // getter is named // setter is named setEnabled:

get { } enabled


objc attribute can be used to change the name of an Objective-C method var enabled: Bool { // property is named enabled


143/173

var enabled: Bool {

set { }}


@objc(isEnabled) get { } isEnabled


objc attribute can be used to change the name of an Objective-C method var enabled: Bool { // property is named enabled


144/173

var enabled: Bool {

set { }}

Or the name of a class

@objc(ABCMyDocument) class MyDocument : UIDocument { // }


@objc(isEnabled) get { } isEnabled


145/173

CF Interoperability

CF in Objective-C

void drawGradientRect(CGContextRef context, CGColorRef startColor, CGColorRef endColor, CGFloat width, CGFloat height) {


146/173

}

CF in Objective-C



147/173

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();NSArray *colors = @[(__bridge id)startColor, (__bridge id)endColor];CGFloat locations[2] = {0.0, 1.0};CGGradientRef gradient = CGGradientCreateWithColors(colorSpace,

(CFArrayRef)colors, locations);

}


CF in Objective-CBridge casts


148/173

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();NSArray *colors = @[ (__bridge id) startColor, (__bridge id) endColor];CGFloat locations[2] = {0.0, 1.0};CGGradientRef gradient = CGGradientCreateWithColors(colorSpace,

(CFArrayRef) colors, locations);

}


CF in Objective-C Three kinds of arrays


149/173


( CFArrayRef )colors, locations);

}

CF in Objective-C



150/173


(CFArrayRef)colors, locations);

CGPoint startPoint = CGPointMake (width / 2, 0);CGPoint endPoint = CGPointMake (width / 2, height);

CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, 0);

}


151/173

CF in Swift

func drawGradientRect(context: CGContext, startColor: CGColor, endColor: CGColor, width: CGFloat, height: CGFloat) {


152/173

}


Managed CF Objects


153/173

let colorSpace = CGColorSpaceCreateDeviceRGB()

}


154/173


Managed CF Objects


155/173

let colorSpace = CGColorSpaceCreateDeviceRGB()

}// colorSpace automatically released

// inferred as CGColorSpace

Toll-Free Bridging Conversions



156/173

let colorSpace = CGColorSpaceCreateDeviceRGB() let gradient = CGGradientCreateWithColors(colorSpace,[startColor, endColor] ,[0.0, 1.0])

}

C Interoperability



157/173

let colorSpace = CGColorSpaceCreateDeviceRGB() let gradient = CGGradientCreateWithColors(colorSpace,[startColor, endColor],[0.0, 1.0] )

}

Construction of C Structs



158/173

let colorSpace = CGColorSpaceCreateDeviceRGB() let gradient = CGGradientCreateWithColors(colorSpace,[startColor, endColor],[0.0, 1.0])

let startPoint = CGPoint ( x: width / 2, y: 0)let endPoint = CGPoint ( x: width / 2, y: height)CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, 0)

}

Explicitly Bridged APIs

Some CF APIs have not been audited for implicit bridgingCGColorRef CGColorGetRandomColor(void);


159/173

Explicitly Bridged APIs

Some CF APIs have not been audited for implicit bridgingCGColorRef CGColorGetRandomColor(void);


160/173

Swift uses Unmanaged when the ownership convention is unknown func CGColorGetRandomColor() -> Unmanaged

Working with Unmanaged Objects

Unmanaged enables manual memory managementstruct Unmanaged {

f t k U t i dV l () > T // f +0 t


161/173

func takeUnretainedValue() -> T // for +0 returns func takeRetainedValue() -> T // for +1 returns

}



f t k U t i dV l () > T // for +0 ret rns


162/173


}



func takeUnretainedValue() > T // for +0 returns


163/173


}

Use it to work with unaudited CF APIs let color = CGColorGetRandomColor(). takeUnretainedValue ()





164/173


}


// inferred as CGColor





165/173


}


func retain() -> Unmanagedfunc release()func autorelease() -> Unmanaged

// inferred as CGColor

Implicit Bridging

Audit CF APIs to ensure that conform to CF memory conventions

CGColorRef CGColorGetRandomColor(void);


166/173



Implicit Bridging

Audit CF APIs to ensure that conform to CF memory conventions CF_IMPLICIT_BRIDGING_ENABLED



167/173

CGColorRef CGColorGetRandomColor(void);CF_IMPLICIT_BRIDGING_DISABLED


Implicit Bridging

Audit CF APIs to ensure that conform to CF memory conventions CF_IMPLICIT_BRIDGING_ENABLED



168/173

CGColorRef CGColorGetRandomColor(void);CF_IMPLICIT_BRIDGING_DISABLED

Implicit bridging eliminates Unmanagedfunc CGColorGetRandomColor() -> CGColor

Summary

Seamless interoperability between Swift and Objective-C Let the tools help you understand the relationship


169/173

Bridging of Core Cocoa types Prefer native strings, arrays, dictionaries

Automated CF memory management

More Information

Dave DeLongDeveloper Tools Evangelist

delong@apple com


170/173

[email protected]

DocumentationUsing Swift with Cocoa and Objective-Chttp://apple.com

Apple Developer Forums

http://devforums.apple.com

Related Sessions
http://devforums.apple.com/http://devforums.apple.com/


171/173

Labs


172/173


173/173

407 swift interoperability in depth

Documents