This document discusses key differences between Objective-C and Swift including lack of C in Swift, language features like lambda functions, type inference, generics, extensions, protocols, memory management without garbage collection, and differences in arrays, dictionaries, functions, closages, optionals, classes, and protocols. It provides examples of string interpolation, type inference with let, array and dictionary syntax and copying behavior, trailing closures, optionals unwrapping, generics constraints, and extending existing classes.

1. Objective-C without C

2. Language Design
Lambda
Optional
Type Inference Generics
Extension
Protocol
No GC (Objective-C ARC)

3. Hello World
String interpolation (word)
Type Inference
let word = “Swift”

4. Array & Dict
Use similar syntax for Array and Dictionary
The key of dictionary is non-deterministic.

5. Array & Dict
Array and Dictionary are copied when assigned.

6. Function & Lambda
{
(params) -> return type in
statement
}
Trailing lambda.
ajax(param1, label:{lambda})
can be written as
ajax(param1) {lambda}

7. Closure
Closures works like a class, which has instance variables.
var count
{ () -> () in
return count++
}

8. Optional
String? = Optional<String>
You cannot assign nil to variables. Use Optional type if it could be nil.
if let unwraps the optional.
Returns true if it is not nil.

9. Class

10. Protocol
Protocol is interface

11. Generics
func printFullname<T: Fullname>(person: T) {
func printFullname(person: Fullname) {

12. Extension
You can append methods to the existing classes like Ruby Monkey patch.