jarsen’s gists

jarsen / BindThemAll.swift

Created March 18, 2015 21:17

Shows how you can use `bind` and `reduce` to short circuit a bunch of mapping

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

	import UIKit

	public class Box<T> {
	let unbox: T
	init(_ value: T) {
	unbox = value
	}
	}

jarsen / db.swift

Last active August 29, 2015 14:15

Database facade in front of realm that translates to and from our immutable structs

	extension RLMRealm {
	public func write(@noescape transaction: ()->()) {
	self.beginWriteTransaction()
	transaction()
	self.commitWriteTransaction()
	}
	}

	public struct Patient {
	public let info: ModelInfo

jarsen / Pipeline.swift

Last active August 29, 2015 14:14

Pipeline operator inspired by Elixir and http://undefinedvalue.com/2014/07/13/fs-pipe-forward-operator-swift

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

	import UIKit
	import CoreGraphics

	public enum Result<T> {
	case Success(@autoclosure () -> T)
	case Failure(String)

	init(_ value:T) {

jarsen / weird.swift

Created January 29, 2015 16:09

why does this crash?

	func eratosthenes(n: Int) -> [Int]{
	return map(enumerate(Array(1...n))) { (index, number) in
	if number % index == 0 {
	return -1
	}
	else {
	return number
	}
	}
	}

jarsen / ScoreKeeper.swift

Last active September 6, 2019 02:59

example of copy constructor with default values for immutability

	struct Scorekeeper {
	let runningScore: Int
	let climbingScore: Int
	let bikingScore: Int
	let swimmingScore: Int

	init(runningScore: Int = 0, climbingScore: Int = 0, bikingScore: Int = 0, swimmingScore: Int = 0) {
	self.runningScore = runningScore
	self.climbingScore = climbingScore
	self.bikingScore = bikingScore

jarsen / json.swift

Last active August 29, 2015 14:13

Parsing JSON Playground with Result type. Inspired by Haskell, Swiftz, and http://robots.thoughtbot.com/efficient-json-in-swift-with-functional-concepts-and-generics

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

	import Foundation

	infix operator >>- { associativity left precedence 150 } // Bind
	infix operator <^> { associativity left } // Functor's fmap (usually <$>)
	infix operator <*> { associativity left } // Applicative's apply

	public typealias JSON = AnyObject
	public typealias JSONObject = Dictionary<String, JSON>

jarsen / List.swift

Created December 24, 2014 20:12

Functional linked list implemented in Swift. Inspired by functional data structure chapter in Functional Programming in Swift, and had to look at Swiftz to figure out it needed the @autoclosure... haven't quite figured out why but otherwise it seems to get into an infinite loop.

	enum List<T> : Printable {
	case Empty
	case Node(@autoclosure() -> T, Box<List<T>>)

	init(_ head: T, _ tail: Box<List<T>>) {
	self = .Node(head, tail)
	}

	var description: String {
	get {

jarsen / composition.swift

Last active August 29, 2015 14:12

swift function composition using UTF-8 ring operator

	infix operator ∘ {}

	func ∘<A,B,C>(f:B->C, g:A->B) -> (A->C) {
	return compose(f, g)
	}

	func compose<A,B,C>(f:B->C, g:A->B) -> (A->C) {
	return { x in f(g(x)) }
	}

jarsen / reverseInt.hs

Created December 24, 2014 00:16

haskell reverseInt implementation

	reverseInt :: (Integral a) => a -> a
	reverseInt x = reverseInt' x 0

	reverseInt' :: (Integral a) => a -> a -> a
	reverseInt' n r
	\| n == 0 = r
	\| otherwise = reverseInt' (quot n 10) (10 * r + n `mod` 10)

jarsen / itoa.hs

Created December 24, 2014 00:15

haskell itoa implementation

	itoa :: (Integral a) => a -> String
	itoa x
	\| x == 0 = "0"
	\| x == 1 = "1"
	\| x == 2 = "2"
	\| x == 3 = "3"
	\| x == 4 = "4"
	\| x == 5 = "5"
	\| x == 6 = "6"
	\| x == 7 = "7"

Jason Larsen jarsen