basics.swift

//: Playground - noun: a place where people can play

import UIKit

var constantString = "Hi"

var str: String? = "Hello, playground"

//str = nil

print(str)

var counter = 0

for counter in 0..<10 {
    guard counter != 2 else { continue }
    if counter != 5 {
        print(counter)
    }
}

var animals = ["chickens", "cows", "ducks"]

animals[1]

animals[1] = "geese"

animals

var cuteness = [
    "chickens": "somewhat",
    "geese": "scary",
    "ducks": "cute"
]

cuteness["ducks"]

for animal in animals {
    cuteness[animal]
}

func transmorgify(species: String, weight: Int) -> Int{
    switch species {
    case "duck": return 0
    default: return -1
    }
}

transmorgify("duck", weight: 10)

let x: Int = 1

if (true) { print("hello") }

let array: [Int] = []


var maybeString: String? = nil

// optional binding
if let string = maybeString {
    string.characters.count
} else {
    0
}

// implicitely unwrapped optionals
let string2: String! = "Hi"

//CLOSURES

// named function
func performMagic(thingy: String) -> String {
    return thingy
}

performMagic("Hey")

var magicFunction = performMagic

magicFunction("Hey")

// anonymous function
var newMagicFunction = {
    (thingy: String) -> String in
    return thingy
}

newMagicFunction("Hey")

// scope of variables and constants for closures
// closure does not capture their value at the time of their definition

var b = 3
var adderFunction: (Int) -> Int = {
    (a: Int) -> Int in
    return a+b
}

adderFunction(1)

b = 2

adderFunction(1)

// if a function or closure is the last argument then you can put it out of () and use only {}