Yan Li eyeplum

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,

Code Signing

A few ways of checking code signatures on OS X.

Simple

$ /usr/bin/codesign --verify --deep --verbose /Applications/Xcode.app
/Applications/Xcode.app: valid on disk
/Applications/Xcode.app: satisfies its Designated Requirement

	Vagrant.configure(2) do \|config\|
	config.vm.box = "hashicorp/precise64"

	# ...

	# This mess of B.S., constructed mostly from <http://apt.llvm.org>, is, as far as I can tell, The
	# Right Way to get non-ancient clang installed on Precise. (Why am I using Precise again? 'cuz
	# Vagrant says so? ಠ_ಠ)
	#
	# Yes, non-ancient clang requires slightly-less-ancient gcc to build ... which isn't available on

	#!/usr/bin/env bash
	set -e

	# This should live in the same directory that contains the swift repository and other tools.

	SRC_DIR=$PWD/swift

	RUN_TESTS=
	if [[ "$1" == "-t" \|\| "$1" == "--test" ]] ; then
	RUN_TESTS="-t"



	// HELPER QUERIES

	void queryValueToData(NSMutableDictionary query, void value) {
	query[(__bridge id)kSecValueRef] = (__bridge id)value ;
	query[(__bridge id)kSecReturnData] = @YES ;
	}

	void queryDataToValue(NSMutableDictionary *query, id data) {

	extension NSView {
	var snapshot: NSImage {
	guard let bitmapRep = bitmapImageRepForCachingDisplayInRect(bounds) else { return NSImage() }
	bitmapRep.size = bounds.size
	cacheDisplayInRect(bounds, toBitmapImageRep: bitmapRep)
	let image = NSImage(size: bounds.size)
	image.addRepresentation(bitmapRep)
	return image
	}
	}

	struct Stack <Element> {
	let values: [Element]

	var elementType: Any {
	get {
	return Element.self
	}
	}
	}

	#!/bin/sh
	red="\033[0;31m"
	yellow="\033[1;33m"
	green="\033[1;32m"
	reset="\033[0m"

	read -a changed_files <<< $(git diff --cached --name-only --raw)

	# check if there're any JS related files in commit
	runTests=false

	headers:
	_ASAsyncTransaction.h
	_ASAsyncTransactionGroup.h
	_ASDisabledPanUITextView.h
	_ASDisplayLayer.h
	_ASDisplayLayerDelegate-Protocol.h
	_ASDisplayView.h
	_ASImageNodeDrawParameters.h
	_ASPendingState.h
	_ASTextNodeCachedMetrics.h

	protobuf
	protobuf-2.6.0
	protobuf-master