From 923a8ed99b1648cc2ece83660ed263492c332afe Mon Sep 17 00:00:00 2001
From: "C. Bess" <cbess@quantumquinn.com>
Date: Sat, 4 Oct 2014 12:08:23 -0500
Subject: - mo betta examples
- add `inout` example
- better `optional` example
- Playground issue has been resolved, uncommented `protocol` example
---
swift.html.markdown | 81 ++++++++++++++++++++++++++++++++++++++---------------
1 file changed, 59 insertions(+), 22 deletions(-)
(limited to 'swift.html.markdown')
diff --git a/swift.html.markdown b/swift.html.markdown
index 77047355..ffe6cac2 100644
--- a/swift.html.markdown
+++ b/swift.html.markdown
@@ -13,6 +13,9 @@ The official [Swift Programming Language](https://itunes.apple.com/us/book/swift
See also Apple's [getting started guide](https://developer.apple.com/library/prerelease/ios/referencelibrary/GettingStarted/LandingPage/index.html), which has a complete tutorial on Swift.
```swift
+// import a module
+import UIKit
+
//
// MARK: Basics
//
@@ -26,7 +29,7 @@ println("Hello, world")
var myVariable = 42
let øπΩ = "value" // unicode variable names
-let myConstant = 3.1415926
+let π = 3.1415926
let convenience = "keyword" // contextual variable name
let weak = "keyword"; let override = "another keyword" // statements can be separated by a semi-colon
let `class` = "keyword" // backticks allow keywords to be used as variable names
@@ -34,9 +37,24 @@ let explicitDouble: Double = 70
let intValue = 0007 // 7
let largeIntValue = 77_000 // 77000
let label = "some text " + String(myVariable) // Casting
-let piText = "Pi = \(myConstant), Pi 2 = \(myConstant * 2)" // String interpolation
-var optionalString: String? = "optional" // Can be nil
-optionalString = nil
+let piText = "Pi = \(π), Pi 2 = \(π * 2)" // String interpolation
+var someOptionalString: String? = "optional" // Can be nil
+
+if someOptionalString != nil {
+ // I am not nil
+ if someOptionalString!.hasPrefix("opt") {
+ println("has the prefix")
+ }
+
+ let empty = someOptionalString?.isEmpty
+}
+someOptionalString = nil
+
+if let someStringConstant = someOptionalString {
+ // has Some value
+}
+
+// AnyObject == id
/*
Comment here
@@ -84,9 +102,10 @@ for (key, value) in dict {
}
// for loop (range)
-for i in -1...1 { // [-1, 0, 1]
+for i in -1...shoppingList.count {
println(i)
}
+shoppingList[1...2] = ["steak", "peacons"]
// use ..< to exclude the last number
// while loop
@@ -123,14 +142,14 @@ default: // required (in order to cover all possible input)
// Function with Swift header docs (format as reStructedText)
/**
- A greet operation
+A greet operation
- - A bullet in docs
- - Another bullet in the docs
+- A bullet in docs
+- Another bullet in the docs
- :param: name A name
- :param: day A day
- :returns: A string containing the name and day value.
+:param: name A name
+:param: day A day
+:returns: A string containing the name and day value.
*/
func greet(name: String, day: String) -> String {
return "Hello \(name), today is \(day)."
@@ -141,9 +160,16 @@ greet("Bob", "Tuesday")
func getGasPrices() -> (Double, Double, Double) {
return (3.59, 3.69, 3.79)
}
+let pricesTuple = getGasPrices()
+let price = pricesTuple.2 // 3.79
+println("Gas price: \(price)")
// Variadic Args
-func setup(numbers: Int...) {}
+func setup(numbers: Int...) {
+ // its an array
+ let number = numbers[0]
+ let argCount = numbers.count
+}
// Passing and returning functions
func makeIncrementer() -> (Int -> Int) {
@@ -155,6 +181,17 @@ func makeIncrementer() -> (Int -> Int) {
var increment = makeIncrementer()
increment(7)
+// pass by ref
+func swapTwoInts(inout a: Int, inout b: Int) {
+ let tempA = a
+ a = b
+ b = tempA
+}
+var someIntA = 7
+var someIntB = 3
+swapTwoInts(&someIntA, &someIntB)
+println(someIntB) // 7
+
//
// MARK: Closures
@@ -197,7 +234,7 @@ print(numbers) // [3, 6, 18]
// Structures and classes have very similar capabilites
struct NamesTable {
let names: [String]
-
+
// Custom subscript
subscript(index: Int) -> String {
return names[index]
@@ -239,7 +276,7 @@ internal class Rect: Shape {
sideLength = newValue / 4
}
}
-
+
// Lazily load a property
// subShape remains nil (uninitialized) until getter called
lazy var subShape = Rect(sideLength: 4)
@@ -255,8 +292,9 @@ internal class Rect: Shape {
}
init(sideLength: Int) {
- super.init()
self.sideLength = sideLength
+ // always super.init last when init custom properties
+ super.init()
}
func shrink() {
@@ -313,7 +351,7 @@ enum Suit {
//
// `protocol`s can require that conforming types have specific
-// instance properties, instance methods, type methods,
+// instance properties, instance methods, type methods,
// operators, and subscripts.
protocol ShapeGenerator {
@@ -321,7 +359,6 @@ protocol ShapeGenerator {
func buildShape() -> Shape
}
-/*
// Protocols declared with @objc allow optional functions,
// which allow you to check for conformance
@objc protocol TransformShape {
@@ -331,17 +368,17 @@ protocol ShapeGenerator {
class MyShape: Rect {
var delegate: TransformShape?
-
+
func grow() {
sideLength += 2
-
+
if let allow = self.delegate?.canReshape?() {
// test for delegate then for method
self.delegate?.reshaped?()
}
}
}
-*/
+
//
// MARK: Other
@@ -363,7 +400,7 @@ extension Int {
var customProperty: String {
return "This is \(self)"
}
-
+
func multiplyBy(num: Int) -> Int {
return num * self
}
@@ -372,7 +409,7 @@ extension Int {
println(7.customProperty) // "This is 7"
println(14.multiplyBy(2)) // 42
-// Generics: Similar to Java. Use the `where` keyword to specify the
+// Generics: Similar to Java and C#. Use the `where` keyword to specify the
// requirements of the generics.
func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? {
--
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