mattdenner

I’ve been writing a load of Swift code recently for work and this has lead me into the world of typed functional programming. The app needs to build certain objects from a comma separated string, and this lead me to applicative functors, which lead me to brain ache but enlightenment. So here’s my thoughts on how I got to understand these a little better.

All of the code is in Swift, so less clean than Haskell. I’m also only a about 6 weeks into Swift development so I probably haven’t got all of the idioms right. I’ve avoided the optional shorthand wherever possible here, preferring Optional<Type> over Type? because I believe the latter is hiding something that helps understand this code in the context of other generic classes.

It’s also long! I think it’s probably the longest blog post I’ve ever written but I found it interesting and useful, for myself, to write. If you’re one of those people who skip to the end of a book to find out whodunit then I’ve included

mattt

Season's Greetings, NSHipsters!

As the year winds down, and we take a moment to reflect on our experiences over the past months, one thing is clear: 2014 has been an incredible year professionally for Apple developers. So much has happened in such a short timespan, and yet it's hard to remember our relationship to Objective-C before Swift, or what APIs could have captivated our imagination as much as iOS 8 or WatchKit.

It's an NSHipster tradition to ask you, dear readers, to send in your favorite tips and tricks from the past year for publication over the New Year's holiday. This year, with the deluge of new developments—both from Cupertino and the community at large—there should be no shortage of interesting tidbits to share.

Submit your favorite piece of Swift or Objective-C trivia, framework arcana, hidden Xcode feature, or anything else you think is cool, and you could have it featured in the year-end blowout article. Just comment on this gist below!

If you're wondering about what to post, look to

phatak-dev

#Compilng You need g++ 4.9 to compile this code. Follow these steps to install g++-4.9

After installing run the following command to compile

/usr/bin/g++-4.9 -std=c++11 lambda.cpp

#Running

./a.out

davedelong

#!/usr/bin/swift

import Foundation

func scanForRepositories(directory: NSURL, root: NSURL) {
    let fileManager = NSFileManager.defaultManager()
    
    let options: NSDirectoryEnumerationOptions = .SkipsSubdirectoryDescendants | .SkipsPackageDescendants
    if let contents = fileManager.contentsOfDirectoryAtURL(directory, includingPropertiesForKeys: [NSURLIsDirectoryKey], options: options, error: nil) {
        let urls = contents as Array<NSURL>

airspeedswift

// See @SwiftLDN's tweet for a short description of the Luhn algorithm:
//   https://twitter.com/SwiftLDN/status/529412592834338817
// or Wikipedia for a longer one.
//   http://en.wikipedia.org/wiki/Luhn_algorithm
//
// Only meant to show extending Swift's lazy() for infotainment purposes,
// not necessarily recommending best or even good practices!
//
// Alternative, saner, solutions here:

steipete

BOOL PSPDFSystemFunctionOverriddenInCategory(Class theClass, SEL selector, NSString *__autoreleasing* categoryName) {
    NSCParameterAssert(theClass);
    NSCParameterAssert(selector);

    Dl_info info;
    if (dladdr(class_getMethodImplementation(theClass, selector), &info)) {
        // /System/Library/Frameworks is a common denominator, some methods are in /usr/lib/libobjc.A.dylib
        // Custom app is in /private/var/mobile/Containers/Bundle/Application/<UID>/PSPDFCatalog.app/PSPDFCatalog
        if (!strstr(info.dli_fname, "/System/Library") && !strstr(info.dli_fname, "/usr/lib")) {
            if (categoryName) *categoryName = @(info.dli_sname);

steipete

@interface FullscreenWindow : UIWindow @end
@implementation FullscreenWindow

- (void)setRootViewController:(UIViewController *)rootVC {
    // Try to clear the existing interface orientation, fixes rdar://18906964.
    // Apparantly in iOS 8.1 the interface orientation doesn't correctly clears out,
    // which then leads to weird rotation issues.
    @try {[rootVC setValue:@(UIInterfaceOrientationPortrait) forKey:NSStringFromSelector(@selector(interfaceOrientation))];}
    @catch (NSException *exception) {}
    [super setRootViewController:rootVC];

alskipp

// Swift 2.0

/* Function composition operator */
infix operator •> { associativity left precedence 150 }
func •> <A,B,C> (f:A -> B, g:B -> C ) -> A -> C {
  return { g(f($0)) }
}

extension Array where T: IntegerType {
  func sum() -> T {

garybernhardt

require "erb"
require "pathname"

DOT_TEMPLATE=<<-END
digraph {
size="20,20";
overlap=false;
sep=0.4;
graph [fontname=Helvetica,fontsize=10];
node [fontname=Helvetica,fontsize=10];

steipete

CGRect PSPDFRectSafeInset(CGRect rect, CGFloat dx, CGFloat dy) {
    CGRect insetRect = CGRectInset(rect, dx, dy);
    if (CGRectIsNull(insetRect)) {
        insetRect = CGRectMake(CGRectGetMidX(rect), CGRectGetMidY(rect), 0.f, 0.f);
    }
    return insetRect;
}