TweetFollow Us on Twitter

Style For Cocoa Programmers

Volume Number: 21 (2005)
Issue Number: 7
Column Tag: Programming

Tips From Big Nerd Ranch

Style For Cocoa Programmers

by Aaron Hillegass, Chris Campbell, Marquis Logan

As developers and teachers, we spend a lot of time dealing with issues of style. Not just because we like to look cool for the ladies; code that is written by a stylish programmer is easier to read and maintain. The Cocoa community has developed idioms, and if you want other developers to be able to easily comprehend your code, you should follow those idioms.

Issue #1: Whitespace

Here is a perfect setter method that explicitly invokes key-value observing:

- (void)setBorderColor:(Color *)c
{
    if (c == borderColor) {
        return;
    }
    [self willChangeValueForKey:@"borderColor"];
    [c retain];
    [borderColor release];
    borderColor = c;
    [self didChangeValueForKey:@"borderColor"];
}

Notice the use of whitespace. In particular, we do not put spaces after colons. We do not put spaces after the type of the parameter (That is, "(Dog *)").

Also, notice that there are no comments. What this method does is self-evident from its name. Too many comments can be just as annoying as too few.

Issue #2: Grouping Methods

In an implementation file, methods should be grouped in a meaningful manner. In particular, we try to follow this order:

   Class methods
   Initializers and dealloc
   copyWithZone:
   isEqual:
   hash
   initWithCoder: and encodeWithCoder:
   action methods
   other methods (subgroup meaningfully)
   delegate methods
   accessor methods (in setter/getter pairs)

Use #pragma mark to show where a group of methods begins. The information will show up in the popup in Xcode. For example, you might insert these lines:

#pragma mark Coding methods
#pragma mark Color metrics
#pragma mark Accessors

So that your Xcode popup would look like this:


Figure 1.

Issue #3: Naming methods

If you have a method that returns the brightness of a border, it should be named thusly:

- (float)borderBrightness;

We do not put articles on method names:

- (float)theBorderBrightness;

We do not prefix methods with get-:

- (float)getBorderBrightness;

The exception to this rule is if the method is pass-by-reference:

float r, g, b;
[borderColor getRed	:&r 
              blue	:&b 
             green	:&g 
             alpha	:NULL];

If a method takes one argument and is prefixed with set-, it should be an accessor. In particular, an action method should never be prefixed with set-.

Issue #4: What Goes In The .h File

The primary purpose of your .h file is so that I can create an instance of your class and send messages to it. Many people put too much information in their .h files. Don't declare any of the following in the .h file:

1) Delegate methods.

2) Private methods.

3) Any methods in a protocol that you conform to. For example, if you have:

@interface Chowder : NSObject <NSCopying>

There is no reason to declare copyWithZone: in your .h file.

4) Any inherited or overridden methods.

Issue #5: Declaring Local Variables

Declare temporary variable in a "just-in-time" manner. When I'm reading your code, I don't want to have to scroll to the beginning of the method to figure out the type of a local variable. Move the declaration as close to the first use as possible.

The Analysis and Design Workshop

In a short column, it is easy to discuss small issues like code formatting and variable naming. For larger and deeper issues, we need a much bigger forum. At the ranch in August, we are hosting an "Analysis and Design Workshop." John Graziano, who had a major part in the design of Xcode, WebObjects Builder, and many of the animation systems at Pixar, will lecture and guide hands-on exercises that teach good design practices. He is going to focus on creating designs that make change and maintenance easy. John started developing these ideas at NeXT, and they have received much acclaim within NeXT, Apple, and Pixar. Bring your specifications, and go home with the beginnings of a really good design for your app. The workshop is August 15 - 19 in Atlanta. We hope to see you there.


Aaron Hillegass, Chris Campbell, Marquis Logan

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

calibre 3.8.0 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
Carbon Copy Cloner 5.0.2 - Easy-to-use b...
Carbon Copy Cloner backups are better than ordinary backups. Suppose the unthinkable happens while you're under deadline to finish a project: your Mac is unresponsive and all you hear is an ominous,... Read more
Evernote 6.12.3 - Create searchable note...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
Default Folder X 5.1.6 - Enhances Open a...
Default Folder X attaches a toolbar to the right side of the Open and Save dialogs in any OS X-native application. The toolbar gives you fast access to various folders and commands. You just click on... Read more
Geekbench 4.1.2 - Measure processor and...
Geekbench provides a comprehensive set of benchmarks engineered to quickly and accurately measure processor and memory performance. Designed to make benchmarks easy to run and easy to understand,... Read more
GraphicConverter 10.5 - $39.95
GraphicConverter is an all-purpose image-editing program that can import 200 different graphic-based formats, edit the image, and export it to any of 80 available file formats. The high-end editing... Read more
Dropbox 35.4.20 - Cloud backup and synch...
Dropbox is an application that creates a special Finder folder that automatically syncs online and between your computers. It allows you to both backup files and keep them up-to-date between systems... Read more
XMind 8 Update 4 - Popular mind mapping...
XMind is the most popular mind mapping tool. Millions of people use XMind to clarify thinking, manage complex information, run brainstorming and get work organized. It couldn't be easier to get... Read more
Safari Technology Preview 11.1 - The new...
Safari Technology Preview contains the most recent additions and improvements to WebKit and the latest advances in Safari web technologies. And once installed, you will receive notifications of... Read more
Chromium 61.0.3163.91 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 61.0.3163.91: Release notes were unavailable... Read more

Stormbound: Kingdom Wars guide - how to...
Stormbound: Kingdom Wars is an excellent new RTS turned card battler out now on iOS and Android. Lovers of strategy will get a lot of enjoyment out of Stormbound's chess-like mechanics, and it's cardbased units are perfect for anyone who loves the... | Read more »
The best AR apps and games on iOS right...
iOS 11 has officially launched, and with it comes Apple's ARKit, a helpful framework that makes it easier than ever for developers to create mobile AR experiences. To celebrate the occassion, we're featuring some of the best AR apps and games on... | Read more »
Phoenix Wright: Ace Attorney - Spirit of...
Phoenix Wright: Ace Attorney - Spirit of Justice 1.00.00 Device: iOS Universal Category: Games Price: $.99, Version: 1.00.00 (iTunes) Description: ************************************************※IMPORTANT※・Please read the “When... | Read more »
Kpressor (Utilities)
Kpressor 1.0.0 Device: iOS Universal Category: Utilities Price: $4.99, Version: 1.0.0 (iTunes) Description: The ultimate ZIP compression application for iPhone and iPad. - Full integration of iOS 11 with support for multitasking.-... | Read more »
Find out how you can save £35 and win a...
Nothing raises excitement like a good competition, and we’re thrilled to announce our latest contest. We’ll be sending one lucky reader and a friend to the Summoners War World Arena Championship at Le Comedia in Paris on October 7th. It’s the... | Read more »
Another Lost Phone: Laura's Story...
Another Lost Phone: Laura's Story 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Another Lost Phone is a game about exploring the social life of a young woman whose phone you have just... | Read more »
The Witness (Games)
The Witness 1.0 Device: iOS Universal Category: Games Price: $9.99, Version: 1.0 (iTunes) Description: You wake up, alone, on a strange island full of puzzles that will challenge and surprise you. You don't remember who you are, and... | Read more »
Egg, Inc. guide - how to build your gold...
Egg, Inc.'s been around for some time now, but don't you believe for one second that this quirky clicker game has gone out of style. The game keeps popping up on Reddit and other community forums thanks to the outlandish gameplay (plus, the... | Read more »
The best deals on the App Store this wee...
Good news, everyone! Your favorite day of the week has arrived at last -- it's discount roundup day! This fine Wednesday evening we're gathering up the hottest deals on the App Store. We've got action platformers, we've got puzzle games, we've got... | Read more »
Morphite (Games)
Morphite 1.08 Device: iOS Universal Category: Games Price: $7.99, Version: 1.08 (iTunes) Description: | Read more »

Price Scanner via MacPrices.net

Apple Offering Up To $455 Credit Toward iPhon...
iPhone 8 and 8 Plus are now available at the Apple Store, and you can receive up to $375 credit toward a new iPhone purchase when you trade in your eligible smartphone. Photo Courtesy Apple Just... Read more
AnyTrans Offers iOS Users Three Ways For Movi...
iMobie Inc. today announceed AnyTrans v6.0.1, which now can help iOS users move all data to iPhone 8/8 Plus seamlessly. The software is available both on Mac and Windows and fully able to move all... Read more
Snag a 13-inch 2.3GHz MacBook Pro for $100 of...
B&H Photo has 2017 13″ 2.3GHz MacBook Pros in stock today and on sale for $100 off MSRP, each including free shipping plus NY & NJ sales tax only: – 13-inch 2.3GHz/128GB Space Gray MacBook... Read more
Verizon offers new iPhone 8 for $100-$300 off...
Verizon is offering the new iPhone 8 for up to $300 off MSRP with an eligible trade-in: • $300 off: iPhone 6S/6S Plus/7/7 Plus, Google Pixel XL, LG G6, Moto Z2 Force, Samsung Galaxy S7/S7 edge/S8/S8... Read more
Apple Refurbished 2017 13-inch MacBook Pros a...
Apple has Certified Refurbished 2017 13″ Touch Bar MacBook Pros in stock today and available for $200-$300 off MSRP. A standard Apple one-year warranty is included with each MacBook, and shipping is... Read more
OWC USB-C Travel Dock with 5 Ports Connectivi...
OWC have announced the new OWC USB-C Travel Dock, the latest addition to their line of connectivity solutions. The USB-C Travel Dock lets you connect its integrated USB-C cable to a Mac or PC laptop... Read more
Pelican Products, Inc. Unveils Cases For All...
Pelican Products, Inc. has announced the launch of its full line of cases including Voyager, Adventurer, Protector, Ambassador, Interceptor (for the Apple iPhone 8 and 8 Plus backwards compatible... Read more
$100 off new 2017 13-inch MacBook Airs
B&H Photo has 2017 13″ MacBook Airs on sale today for $100 off MSRP including free shipping. B&H charges NY & NJ sales tax only: – 13″ 1.8GHz/128GB MacBook Air (MQD32LL/A): $899, $100 off... Read more
Apple restocks Certified Refurbished 13-inch...
Apple has Certified Refurbished 2015 13″ MacBook Airs available starting at $719 and 2016 models available starting at $809. An Apple one-year warranty is included with each MacBook, and shipping is... Read more
Is iPhone X Really The Future Of The Smartpho...
Should iPhone X even be called a telephone? It does of course support telephony and texting, but its main feature set is oriented to other things. It is also debatable whether it makes any rational... Read more

Jobs Board

Specialist - Retail Customer Services and Sal...
The position listed below is not with Tennessee Interviews but with Apple , Inc. Tennessee Interviews is a private organization that works in collaboration with Read more
Specialist - Retail Customer Services and Sal...
The position listed below is not with South Carolina Interviews but with Apple , Inc. South Carolina Interviews is a private organization that works in collaboration Read more
Behavior Technician with *Apple* Consulting...
The position listed below is not with Washington Interviews but with APPLE CONSULTING Washington Interviews is a private organization that works in collaboration Read more
Infection Control RN with *Apple* Rehab - A...
The position listed below is not with Georgia Interviews but with Apple Rehab Georgia Interviews is a private organization that works in collaboration with Read more
Specialist - Retail Customer Services and Sal...
The position listed below is not with South Carolina Interviews but with Apple , Inc. South Carolina Interviews is a private organization that works in collaboration Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.