staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

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This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

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nadavrot

High-Performance Matrix Multiplication

This is a short post that explains how to write a high-performance matrix multiplication program on modern processors. In this tutorial I will use a single core of the Skylake-client CPU with AVX2, but the principles in this post also apply to other processors with different instruction sets (such as AVX512).

Intro

Matrix multiplication is a mathematical operation that defines the product of

piscisaureus

Locate the section for your github remote in the .git/config file. It looks like this:

[remote "origin"]
	fetch = +refs/heads/*:refs/remotes/origin/*
	url = git@github.com:joyent/node.git

Now add the line fetch = +refs/pull/*/head:refs/remotes/origin/pr/* to this section. Obviously, change the github url to match your project's URL. It ends up looking like this:

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

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/

chriseidhof

import SwiftUI

extension CGPoint {
    static func *(lhs: Self, rhs: CGFloat) -> Self {
        .init(x: lhs.x * rhs, y: lhs.y * rhs)
    }
}

// Idea: https://www.framer.com/showcase/project/lo2Qka8jtPXrjzZaPZdB/

Blankwonder

# You can download this config from: http://surge.run/config-example/ios.conf
# Edit with your computer and copy back to iOS device via iTunes, URL, AirDrop 
# or iCloud Drive
# Version 2.0

[General]
# Log level: warning, notify, info, verbose (Default: notify)
loglevel = notify
# Skip domain or IP range. These hosts will not be processed by Surge Proxy. 
# (In macOS version when Set as System Proxy enabled, these hosts will be

steipete

// Taken from http://PSPDFKit.com. This snippet is under public domain.
#define UIKitVersionNumber_iOS_7_0 0xB57
BOOL PSPDFIsUIKitFlatMode(void) {
    static BOOL isUIKitFlatMode = NO;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        // We get the modern UIKit if system is running >= iOS 7 and we were linked with >= SDK 7.
        if (kCFCoreFoundationVersionNumber >= kCFCoreFoundationVersionNumber_iOS_7_0) {
            isUIKitFlatMode = (NSVersionOfLinkTimeLibrary("UIKit") >> 16) >= UIKitVersionNumber_iOS_7_0;
        }

steipete

// Taken from the commercial iOS PDF framework http://pspdfkit.com.
// Copyright (c) 2014 Peter Steinberger, PSPDFKit GmbH. All rights reserved.
// Licensed under MIT (http://opensource.org/licenses/MIT)
//
// You should only use this in debug builds. It doesn't use private API, but I wouldn't ship it.

// PLEASE DUPE rdar://27192338 (https://openradar.appspot.com/27192338) if you would like to see this in UIKit.

#import <objc/runtime.h>
#import <objc/message.h>

steipete

NSString *const PSPDFApplicationDidReceiveMemoryWarningNotification = @"PSPDFApplicationDidReceiveMemoryWarningNotification";

// Test with sudo memory_pressure -l critical. Don't forget to re-set afterwards!
__attribute__((constructor)) static void PSPDFInstallLowMemoryNotificationWarningMac(void) {
    static dispatch_source_t source;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        source = dispatch_source_create(DISPATCH_SOURCE_TYPE_MEMORYPRESSURE, 0, DISPATCH_MEMORYPRESSURE_WARN|DISPATCH_MEMORYPRESSURE_CRITICAL, dispatch_get_main_queue());
        dispatch_source_set_event_handler(source, ^{
            dispatch_source_memorypressure_flags_t pressureLevel = dispatch_source_get_data(source);