IOS开发-Swift新语言初见

Safe

Swift pairs increased type safety with type inference, restricts direct access to pointers, and automatically manages memory—making it easy to create secure, stable software.

func

configureLabels(labels:

UILabel[]) {

let

labelTextColor =
UIColor.greenColor()

for

label
in
labels {

//
label inferred to be UILabel

label.textColor
=
labelTextColor

}

}

Modern

Swift includes optionals, generics, tuples, and other modern language features. Inspired by and improving upon Objective-C, Swift code feels natural to read and write.

let

cities = ["London",

"San Francisco",
"Tokyo",
"Barcelona",
"Sydney"]

let

sortedCities =
sort(cities)
{
$0 <
$1 }

if

let
indexOfLondon =
find(sortedCities,

"London") {

println("London
is city number \(indexOfLondon
+
1)
in the list")

}

Powerful

Take advantage of powerful pattern matching in Swift to write simple, expressive code. Format strings naturally with string interpolation. Use frameworks like Foundation and UIKit directly from Swift.

let

size = (20,

40)

switch

size {

case

let (width,

height)
where
width ==
height:

println("square
with sides \(width)")

case
(1..10,

1..10):

println("small
rectangle")

case

let (width,

height):

println("rectangle
with width \(width)
and height \(height)")

}

Interactive

Use playgrounds to experiment with new technologies, analyze problems, and prototype user interfaces.

Fast

The Swift compiler applies advanced code analysis to tune your code for performance, letting you focus on writing great apps instead of on implementing complex optimizations.