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@htinlinn
htinlinn / DecodableRoot.swift
Last active June 3, 2023 21:10
Decode JSON at root level based on a key
extension JSONDecoder {
func decode<T: Decodable>(_ type: T.Type, from data: Data, keyedBy key: String?) throws -> T {
if let key = key {
// Pass the top level key to the decoder.
userInfo[.jsonDecoderRootKeyName] = key
let root = try decode(DecodableRoot<T>.self, from: data)
return root.value
} else {
@nyg
nyg / MemoryAddress.swift
Last active July 9, 2024 03:38
Get the memory address of both class and structure instances in Swift.
// https://stackoverflow.com/a/45777692/5536516
import Foundation
struct MemoryAddress<T>: CustomStringConvertible {
let intValue: Int
var description: String {
let length = 2 + 2 * MemoryLayout<UnsafeRawPointer>.size
@lattner
lattner / async_swift_proposal.md
Last active December 28, 2024 11:11 — forked from oleganza/async_swift_proposal.md
Concrete proposal for async semantics in Swift

Async/Await for Swift

Introduction

Modern Cocoa development involves a lot of asynchronous programming using closures and completion handlers, but these APIs are hard to use. This gets particularly problematic when many asynchronous operations are used, error handling is required, or control flow between asynchronous calls gets complicated. This proposal describes a language extension to make this a lot more natural and less error prone.

This paper introduces a first class Coroutine model to Swift. Functions can opt into to being async, allowing the programmer to compose complex logic involving asynchronous operations, leaving the compiler in charge of producing the necessary closures and state machines to implement that logic.

@mayoff
mayoff / main.m
Created May 31, 2017 15:43
adding objc_boxable to CoreGraphics structs
@import Foundation;
@import CoreGraphics;
typedef struct __attribute__((objc_boxable)) CGPoint CGPoint;
typedef struct __attribute__((objc_boxable)) CGSize CGSize;
typedef struct __attribute__((objc_boxable)) CGRect CGRect;
typedef struct __attribute__((objc_boxable)) CGVector CGVector;
int main(int argc, const char * argv[]) {
@autoreleasepool {
@andymatuschak
andymatuschak / States-v3.md
Last active April 14, 2025 22:47
A composable pattern for pure state machines with effects (draft v3)

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,

@andymatuschak
andymatuschak / gist:2b311461caf740f5726f
Created December 28, 2014 18:17
A pragmatic and intentionally non-abstract solution to JSON decoding / initialization that doesn't require learning about five new operators.
struct User {
let id: Int
let name: String
let email: String?
}
extension User: JSONDecodable {
static func create(id: Int, name: String, email: String?) -> User {
return User(id: id, name: name, email: email)
}
@cabeca
cabeca / simulator_populator
Created September 23, 2014 21:30
This script removes and recreates all simulators in Xcode 6.
#!/usr/bin/env ruby
device_types_output = `xcrun simctl list devicetypes`
device_types = device_types_output.scan /(.*) \((.*)\)/
runtimes_output = `xcrun simctl list runtimes`
runtimes = runtimes_output.scan /(.*) \(.*\) \((com.apple[^)]+)\)$/
devices_output = `xcrun simctl list devices`
devices = devices_output.scan /\s\s\s\s(.*) \(([^)]+)\) (.*)/
@prendio2
prendio2 / SUPTableViewController.m
Created March 26, 2014 15:05
Custom viewWillApear to restore selected row when transition is cancelled
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
NSIndexPath *selectedRowIndexPath = [self.tableView indexPathForSelectedRow];
if (selectedRowIndexPath) {
[self.tableView deselectRowAtIndexPath:selectedRowIndexPath animated:YES];
[[self transitionCoordinator] notifyWhenInteractionEndsUsingBlock:^(id<UIViewControllerTransitionCoordinatorContext> context) {
if ([context isCancelled]) {
[self.tableView selectRowAtIndexPath:selectedRowIndexPath animated:NO scrollPosition:UITableViewScrollPositionNone];
@jspahrsummers
jspahrsummers / GHReadWriteQueue.h
Last active December 22, 2016 16:15
Non-blocking mutual exclusion with readers and writers, for asynchronous operations that may span more than one GCD block (making a single concurrent GCD queue unsuitable).
//
// GHReadWriteQueue.h
// GitHub
//
// Created by Justin Spahr-Summers on 2014-03-24.
// Copyright (c) 2014 GitHub. All rights reserved.
//
#import <Foundation/Foundation.h>
@matthiasplappert
matthiasplappert / gist:9493050
Last active August 29, 2015 13:57
QuickLook Debugging for `UIView`
@interface UIView (MPAdditions)
@end
@implementation UIView (MPAdditions)
- (id)debugQuickLookObject {
if (self.bounds.size.width < 0.0f || self.bounds.size.height < 0.0f) {
return nil;
}