Taking Swift for a Test Flight

description.md

Gist for bnotions.com post – Taking Swift for a Test Flight.

objective-c-blocks.m

// As a local variable:

NSString*(^foo)(NSString *bar) = ^NSString*(NSString *bar) {
    return [NSString stringWithFormat: @"Hello %@", bar];
};

// As a property:

@property (nonatomic, copy) NSString*(^foo)(NSString *bar);

// As a method parameter:

- (void)takeBlock:(NSString*(^)(NSString *bar))foo;

// As an argument to a method call:

[self takeBlock: 
    ^NSString*(NString *bar) {
        return [NSString stringWithFormat: @"Hello %@", bar]
    }
];

// As a typedef:

typedef NSString*(^Foo)(NSString *bar);
Foo foo = ^NSString*(NSString *bar) {
    return [NSString stringWithFormat: @"Hello %@", bar];
};

objective-c-for-loop.m

// For loop that prints "Hello World" 20 times.

for (int = 0; i < 20; i++)
{
    NSLog( @"Hello World" );
}

// For loop that prints "Hello World" 21 times.

for (int = 0; i <= 20; i++)
{
    NSLog( @"Hello World" );
}

swift-closures.swift

// As a local variable:

var foo = { (bar: String) -> String in
    return "Hello " + bar
}

// As a constant and as a property:

let baz = { (bar: String) -> String in
    return "Hello " + bar
}

var foo: String -> String = { 
    get { return baz }
    set { baz = newValue; }
}

// As a method parameter

func takeClosure( foo: String -> String )

// As an argument to a method call:

takeClosure({ (bar: String) -> String in
    return "Hello " + bar
})

// As a typealias (typedef equivalent):

typealias Foo = String -> String
var foo: Foo = { (bar: String) -> String in
    return "Hello " + bar
}

swift-for-loop.swift

// For loop that prints "Hello World" 20 times.

for i in 0..20
{
    println( "Hello World" );
}

// For loop that prints "Hello World" 21 times.

for i in 0...20
{
    println( "Hello World" );
}

swift-inline-string-substitution.swift

let hello = "Hello"
let world = "World"

// Prints "Hello World"

println( "\(hello) \(world)" )

swift-lazy-initialization.swift

class Foo {
    @lazy var bar = Bar();
}

let foo = Foo();

// On initialization of foo, foo.bar is not yet initialized.

foo.bar.baz()

// bar is now initialized when the baz property is accessed.

swift-shorthand-external-parametrization.swift

// Function declaration where the external parameter is the same as the internal parameter

func compare(string1 string1: String, string2 string2: String) -> Bool

// The previous function can be shortened using (#)

func compare(#string1: String, #string2: String) -> Bool

swift-tuples.swift

// Declaring a tuple.

let foo = ("Hello", "World", 1.0 );

// Declaration for a function that returns a tuple

func returnATuple() -> (String, String, Float) {
    return foo;
}