tkersey

Monads and delimited control are very closely related, so it isn’t too hard to understand them in terms of one another. From a monadic point of view, the big idea is that if you have the computation m >>= f, then f is m’s continuation. It’s the function that is called with m’s result to continue execution after m returns.

If you have a long chain of binds, the continuation is just the composition of all of them. So, for example, if you have

m >>= f >>= g >>= h

then the continuation of m is f >=> g >=> h. Likewise, the continuation of m >>= f is g >=> h.

tkersey

{-# LANGUAGE DeriveFunctor #-}

module Main where

type Algebra f a = f a -> a

type Coalgebra f a = a -> f a

newtype Fix f = In { out :: f (Fix f) }

tkersey

Tracker emojis

A list of emojis that are allowed in Pivotal Tracker initials.

Emoji	Unicode
✂	\xE2\x9C\x82
✅	\xE2\x9C\x85
✈	\xE2\x9C\x88
✉	\xE2\x9C\x89

tkersey

Videos

• Introduction to Functional Programming Johannes Weiß - https://vimeo.com/100786088
• ReactiveCocoa at MobiDevDay Andrew Sardone - https://vimeo.com/65637501
• The Future Of ReactiveCocoa Justin Spahr-Summers - https://www.youtube.com/watch?v=ICNjRS2X8WM
• Enemy of the State Justin Spahr-Summers - https://www.youtube.com/watch?v=7AqXBuJOJkY
• WWDC 2014 Session 229 - Advanced iOS Application Architecture and Patterns Andy Matuschak - https://developer.apple.com/videos/play/wwdc2014/229/
• Functioning as a Functionalist Andy Matuschak - https://www.youtube.com/watch?v=rJosPrqBqrA
• Controlling Complexity in Swift Andy Matuschak - https://realm.io/news/andy-matuschak-controlling-complexity/

tkersey

const I = x => x;
const K = x => y => x;
const A = f => x => f(x);
const T = x => f => f(x);
const W = f => x => f(x)(x);
const C = f => y => x => f(x)(y);
const B = f => g => x => f(g(x));
const S = f => g => x => f(x)(g(x));
const P = f => g => x => y => f(g(x))(g(y));
const Y = f => (g => g(g))(g => f(x => g(g)(x)));

tkersey

New Build System Tricks

Command Line

# enable internal menu
defaults write com.apple.dt.Xcode ShowDVTDebugMenu -bool YES

alias xcbuild=$(xcode-select -p)/../SharedFrameworks/XCBuild.framework/Versions/A/Support/xcbuild

tkersey

Build settings reference

Active Build Action (ACTION)

A string identifying the build system action being performed.

Additional SDKs (ADDITIONAL_SDKS)

The locations of any sparse SDKs that should be layered on top of the one specified by Base SDK (SDKROOT). If more than one SDK is listed, the first one has highest precedence. Every SDK specified in this setting should be a "sparse" SDK, for example, not an SDK for an entire macOS release.

Alternate Install Group (ALTERNATE_GROUP)

tkersey

// This example shows how higher-kinded types can be emulated in Swift today.
// It acheives correct typing at the cost of some boilerplate, manual lifting and an existential representation.
// The technique below was directly inspired by the paper Lightweight Higher-Kinded Polymorphism
// by Jeremy Yallop and Leo White found at http://ocamllabs.io/higher/lightweight-higher-kinded-polymorphism.pdf

/// `ConstructorTag` represents a type constructor.
/// `Argument` represents an argument to the type constructor.
struct Apply<ConstructorTag, Argument> {
    /// An existential containing a value of `Constructor<Argument>`
    /// Where `Constructor` is the type constructor represented by `ConstructorTag`

tkersey

import Foundation
import UIKit
import PlaygroundSupport

// --------------------------------------------------------------------------------
// MARK: - operators
// --------------------------------------------------------------------------------

precedencegroup MonoidComposePrecedence {
  associativity: left higherThan: AssignmentPrecedence lowerThan: AdditionPrecedence

tkersey

Verifying my Blockstack ID is secured with the address 1Pgb6MVcG9qhJ6Tnu86FPs5MtY1znYC3wP https://explorer.blockstack.org/address/1Pgb6MVcG9qhJ6Tnu86FPs5MtY1znYC3wP