tclementdev

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

• You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.

• Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

khanlou

import Foundation

final class SafeSyncQueue {

    struct QueueIdentity {
        let label: String
    }

    let queue: DispatchQueue

andymatuschak

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,

bishboria

These links no longer work. Springer have pulled the free plug.

Graduate texts in mathematics

duplicates = multiple editions

A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen

A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen

ohanhi

Learning FP the hard way: Experiences on the Elm language

by Ossi Hanhinen, @ohanhi

with the support of Futurice 💚.

Licensed under CC BY 4.0.

Editorial note

JaviLorbada

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/

jamii

Specification

Out Of The Tarpit

BOOM Analytics: Exploring Data-Centric, Declarative Programming for the Cloud

Dedalus: Datalog in Time and Space

Logic and Lattices for Distributed Programming

jstn

/*
    var t = Timer()
    
    t.start()
    // do something
    t.stop()

    print("took \(t.seconds)")
*/

raphaelschaad

//
//  RSTimingFunction.h
//
//  Created by Raphael Schaad on 2013-09-28.
//  This is free and unencumbered software released into the public domain.
//


#import <UIKit/UIKit.h>

m4tbat

#
# Usage example:
# python path/to/image_tiler.py path/to/huge/image.png 256x256 3
#

import glob
import os
import re
import sys
import subprocess