Swift for-rubyists
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The document provides an overview of Swift programming, including topics like type safety, extendability, and managing external dependencies. It discusses the use of Swift REPL, Alcatraz as a package manager, and how to integrate Objective-C with Swift code. Additionally, it highlights best practices for structuring applications and accessing resources for further learning.
![Type Safety (Cont’d)
• Nil checking is more expressive in Swift
• Chaining optional is a good way to simplify code
• Similar to how things work with CoffeeScript
person.car?.doors[0]?.open()](https://image.slidesharecdn.com/swift-for-rubyists-141225021430-conversion-gate02/85/Swift-for-rubyists-8-320.jpg)
![Extendability
• adding toArray to Range
extension Range {
func toArray() -> [T] {
return [T](self)
}
}
(0...500).toArray()
class Range
def to_array
self.to_a
end
end
(0…500).to_array()
Swift
Ruby](https://image.slidesharecdn.com/swift-for-rubyists-141225021430-conversion-gate02/85/Swift-for-rubyists-9-320.jpg)
![Extendability (cont’d)
• Union of two dictionaries
func + <K,V>(left: Dictionary<K,V>, right: Dictionary<K,V>) -> Dictionary<K,V>
{
var map = Dictionary<K,V>()
for (k, v) in left {
map[k] = v
}
for (k, v) in right {
map[k] = v
}
return map
}
let ab = ["a": 1] + ["b": 2]
class Hash
def +(right)
hash = {}
self.each { |k,v| hash[k] = v }
right.each { |k,v| hash[k] = v }
hash
end
end
ab = {a: 1} + {b: 2}
Swift
Ruby](https://image.slidesharecdn.com/swift-for-rubyists-141225021430-conversion-gate02/85/Swift-for-rubyists-10-320.jpg)
![How Obj-C interfaces
Translate to Swift
• Initializers
• Enums
• Unions???
UITableView *myTableView = [[UITableView alloc] initWithFrame:CGRectZero];
let myTableView = UITableView(frame:CGRectZero)
UIButtonType button_type = UIButtonTypeDetailDisclosure;
var buttonType = UIButtonType.DetailDisclosure](https://image.slidesharecdn.com/swift-for-rubyists-141225021430-conversion-gate02/85/Swift-for-rubyists-16-320.jpg)
![How Obj-C interfaces
Translate to Swift (cont’d)
• Unions Obj-C Wrapper
@interface GyroData: NSObject
@property (nonatomic) float x;
@property (nonatomic) float y;
@property (nonatomic) float z;
@end
@implementation GyroData
@end
+ (GyroData *) getGyro:(TLMGyroscopeEvent *)gyroEvent {
GLKVector3 vector = gyroEvent.vector;
GyroData *result = [GyroData new];
result.x = vector.x;
result.y = vector.y;
result.z = vector.z;
return result;
}
let gyroData = GLKitPolyfill.getGyro(gyroEvent)
swift](https://image.slidesharecdn.com/swift-for-rubyists-141225021430-conversion-gate02/85/Swift-for-rubyists-17-320.jpg)
Swift for-rubyists
- 2. Outline • Swift REPL • Alcatraz (no not the island!) • Type Safety • Extendability • Managing External Dependencies • Obj-C to Swift and Vice Versa • Structuring your application
- 3. Who Am I • Rails/Mobile Developer @ Gastown Labs • Fitness Wearable fanatic… • Entrepreneur, side project: FitnessKPI
- 4. Online Resources • Swift is very young, there are a few good resources - just need to find them NSHipster - posts about iOS Dev and Swift NSScreencast - similar to railcasts CodeSchool - Interactive course to learn Obj-C
- 5. Swift REPL • Run Swift Code from Terminal • No need to load xCode! (YAY!) • Similar to IRB, doesn’t have access to application context • see the `lldb` expression commands • (lldb) expr myVar.val() • http://lldb.llvm.org/lldb-gdb.html
- 6. Alcatraz • xCode sucks. We all know it. • Alcatraz is a package manager for xCode (similar to sublime’s package manager) • Be a hipster, get a dark theme! I use `Sidewalk Chalk`
- 7. Type Safety • Swift is strongly typed and extremely type safe • Optionals are variables that can hold a nil value • In swift, all variables and constants must have a value, unless they are optional let PI:Double = 3.14 var twoPI = PI * 2 var sum:Double? = nil sum = 0 println(sum) // 0 sum = sum + 1 // error! sum is optional sum = sum! + 1 // works! unwraps optional before addition var sum:Double = nil // error Double cannot have a nil value!
- 8. Type Safety (Cont’d) • Nil checking is more expressive in Swift • Chaining optional is a good way to simplify code • Similar to how things work with CoffeeScript person.car?.doors[0]?.open()
- 9. Extendability • adding toArray to Range extension Range { func toArray() -> [T] { return [T](self) } } (0...500).toArray() class Range def to_array self.to_a end end (0…500).to_array() Swift Ruby
- 10. Extendability (cont’d) • Union of two dictionaries func + <K,V>(left: Dictionary<K,V>, right: Dictionary<K,V>) -> Dictionary<K,V> { var map = Dictionary<K,V>() for (k, v) in left { map[k] = v } for (k, v) in right { map[k] = v } return map } let ab = ["a": 1] + ["b": 2] class Hash def +(right) hash = {} self.each { |k,v| hash[k] = v } right.each { |k,v| hash[k] = v } hash end end ab = {a: 1} + {b: 2} Swift Ruby
- 11. Extendability WARNING! PLEASE EXTEND RESPONSIBLY!
- 12. Fun Fact • Swift supports unicode characters for variable names… (i.e. prank friends using google translate). let акулажир = "Shark Fat" let 瘦鲨⻥鱼 = "skinny Shark"
- 13. Managing External Dependencies • Most modern languages have the notion of a package manager. e.g. NPM, Ruby Gems, Bower • In swift we have Cocoapods… or do we? • Can only use Cocoapods with Obj-C code (for now)… :( • http://www.swifttoolbox.io/ - great collection of swift packages
- 14. Accessing Obj-C from Swift • Really easy, only need header bridge.h file and you are set.
- 15. “Objective-C is done fool!” Not quite…
- 16. How Obj-C interfaces Translate to Swift • Initializers • Enums • Unions??? UITableView *myTableView = [[UITableView alloc] initWithFrame:CGRectZero]; let myTableView = UITableView(frame:CGRectZero) UIButtonType button_type = UIButtonTypeDetailDisclosure; var buttonType = UIButtonType.DetailDisclosure
- 17. How Obj-C interfaces Translate to Swift (cont’d) • Unions Obj-C Wrapper @interface GyroData: NSObject @property (nonatomic) float x; @property (nonatomic) float y; @property (nonatomic) float z; @end @implementation GyroData @end + (GyroData *) getGyro:(TLMGyroscopeEvent *)gyroEvent { GLKVector3 vector = gyroEvent.vector; GyroData *result = [GyroData new]; result.x = vector.x; result.y = vector.y; result.z = vector.z; return result; } let gyroData = GLKitPolyfill.getGyro(gyroEvent) swift
- 18. Accessing Swift Code from Obj-C • More difficult, mostly don’t need to do it… • Uses automatically generated header file • Add @objc tag to classes and other interfaces you want to expose to Objective C code. (CoreData needs this)
- 19. Structuring Applications • No strict directory structure to iOS apps • No concept of “folders” but “groups”, need to manually keep in sync • Use the best practices you learned from Rails
- 20. Persistence • CoreData - if your hardcore like that • MagicalRecord - ORM for CoreData • Realm - replacement for CoreData, cross platform and easier workflow
- 21. References • https://signalvnoise.com/posts/3743 • https://signalvnoise.com/posts/3432-why-i-loved- building-basecamp-for-iphone-in-rubymotion • http://realm.io/news/swift-for-rubyists/ • http://www.slideshare.net/josephku/swift-introduction- to-swift-in-ruby • http://www.bignerdranch.com/blog/discover-swift-with- this-one-weird-rubyist/ • http://blog.thefrontiergroup.com.au/2014/09/should- my-company-choose-rubymotion-or-swift/ • Swift (book) • Using Swift with Cocoa and Objective-C
- 22. QUESTIONS?