Yanzhi Wang puttin

A composable pattern for pure state machines with effects

State machines are everywhere in interactive systems, but they're rarely defined clearly and explicitly. Given some big blob of code including implicit state machines, which transitions are possible and under what conditions? What effects take place on what transitions?

There are existing design patterns for state machines, but all the patterns I've seen complect side effects with the structure of the state machine itself. Instances of these patterns are difficult to test without mocking, and they end up with more dependencies. Worse, the classic patterns compose poorly: hierarchical state machines are typically not straightforward extensions. The functional programming world has solutions, but they don't transpose neatly enough to be broadly usable in mainstream languages.

Here I present a composable pattern for pure state machiness with effects,

	// clang -cc1 -analyzer-checker-help
	// OVERVIEW: Clang Static Analyzer Checkers List
	// USAGE: -analyzer-checker <CHECKER or PACKAGE,...>
	//
	// CHECKERS:
	// alpha.core.BoolAssignment Warn about assigning non-{0,1} values to Boolean variables
	// alpha.core.CallAndMessageUnInitRefArg
	// Check for logical errors for function calls and Objective-C message expressions (e.g., uninitialized arguments, null function pointers, and pointer to undefined variables)
	// alpha.core.CastSize Check when casting a malloc'ed type T, whether the size is a multiple of the size of T
	// alpha.core.CastToStruct Check for cast from non-struct pointer to struct pointer

	# The trick is to link the DeviceSupport folder from the beta to the stable version.
	# sudo needed if you run the Mac App Store version. Always download the dmg instead... you'll thank me later :)

	# Support iOS 15 devices (Xcode 13.0) with Xcode 12.5:
	sudo ln -s /Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/15.0 /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport

	# Then restart Xcode and reconnect your devices. You will need to do that for every beta of future iOS versions

	# (A similar approach works for older versions too, just change the version number after DeviceSupport)

	import Cocoa

	// Missing isWord
	func isWord(string: String) -> Bool {
	if let _ = Int(string) { return false }
	let range = NSSpellChecker.shared().checkSpelling(of: string, startingAt: 0)
	return range.location == NSNotFound
	}

	/*:

	import UIKit

	// Swift rewrite challenge
	// Starting point: https://gist.github.com/jkereako/200342b66b5416fd715a#file-scale-and-crop-image-swift

	func scaleAndCropImage(
	image: UIImage,
	toSize size: CGSize,
	fitImage: Bool = true
	) -> UIImage {

	import Foundation

	// Extend String to support regex searching by conforming
	// to CustomStringConvertible
	extension String: CustomStringConvertible {
	public var description: String {return self}
	}

	// Regex support for keys
	public extension Dictionary where Key: CustomStringConvertible {

	#! /usr/bin/env python
	# coding: utf-8

	'''
	auto switch keyboard between different applications

	if you want to change the app list, modify the var 'ignore_list'
	'''

	from AppKit import NSWorkspace, NSWorkspaceDidActivateApplicationNotification, NSWorkspaceApplicationKey

	import Cocoa

	// Note: use of enumeration var in generic is instadeath
	// Note: use of static var in generic is not yet supported

	public protocol EnumConvertible: Hashable {
	init?(hashValue hash: Int)
	static func countMembers() -> Int
	static func members() -> [Self]
	}

	//
	// main.swift
	// pggrep - updated 12/4/15
	// Created by Erica Sadun on 6/17/15.
	// Copyright © 2015 Erica Sadun. All rights reserved.
	//

	import Foundation

	extension String {

	import Cocoa

	/// A wrapper around any type to make Result compile
	class Box<T> {
	let unbox: T

	init(_ value: T) {
	self.unbox = value
	}
	}