GoogleStyleGuide 一个不错的开源项目. 不及格的程序员

推荐一个大众化语言学习的站点: http://code.google.com/p/google-styleguide/

它使用xml+xslt的方式解析成HTML页面,并且循续渐近式的介绍每种(比较大众化的,目前收录了 C++ , JavaScript, Objective-C , 和Python )编程语言 .

可以作为内部培训资料或是初学者使用.

样例:

Background

Objective-C is a very dynamic, object-oriented extension of C. It's designed to be easy to use and read, while enabling sophisticated object-oriented design. It is the primary development language for new applications on Mac OS X and the iPhone. 

Cocoa is one of the main application frameworks on Mac OS X. It is a collection of Objective-C classes that provide for rapid development of full-featured Mac OS X applications. 

Apple has already written a very good, and widely accepted, coding guide for Objective-C. Google has also written a similar guide for C++. This Objective-C guide aims to be a very natural combination of Apple's and Google's general recommendations. So, before reading this guide, please make sure you've read: 
Apple's Cocoa Coding Guidelines 
Google's Open Source C++ Style Guide 


Note that all things that are banned in Google's C++ guide are also banned in Objective-C++, unless explicitly noted in this document. 

The purpose of this document is to describe the Objective-C (and Objective-C++) coding guidelines and practices that should be used for all Mac OS X code. Many of these guidelines have evolved and been proven over time on other projects and teams. Open-source projects developed by Google conform to the requirements in this guide. 

Google has already released open-source code that conforms to these guidelines as part of the Google Toolbox for Mac project (abbreviated GTM throughout this document). Code meant to be shared across different projects is a good candidate to be included in this repository. 

Note that this guide is not an Objective-C tutorial. We assume that the reader is familiar with the language. If you are new to Objective-C or need a refresher, please read The Objective-C Programming Language . 
Example

They say an example is worth a thousand words so let's start off with an example that should give you a feel for the style, spacing, naming, etc. 

An example header file, demonstrating the correct commenting and spacing for an @interface declaration 
 //  GTMFoo.h
 //  FooProject
 //
 //  Created by Greg Miller on 6/13/08.
 //  Copyright 2008 Google, Inc. All rights reserved.
 //

 #import <Foundation/Foundation.h>

 // A sample class demonstrating good Objective-C style. All interfaces,
 // categories, and protocols (read: all top-level declarations in a header)
 // MUST be commented. Comments must also be adjacent to the object they're
 // documenting.
 //
 // (no blank line between this comment and the interface)
 @interface GTMFoo : NSObject {
  @private
   NSString *foo_;
   NSString *bar_;
 }

 // Returns an autoreleased instance of GMFoo. See -initWithString: for details
 // about the argument.
 + (id)fooWithString:(NSString *)string;

 // Designated initializer. |string| will be copied and assigned to |foo_|.
 - (id)initWithString:(NSString *)string;

 // Gets and sets the string for |foo_|.
 - (NSString *)foo;
 - (void)setFoo:(NSString *)newFoo;

 // Does some work on |blah| and returns YES if the work was completed
 // successfuly, and NO otherwise.
 - (BOOL)doWorkWithString:(NSString *)blah;

 @end

An example source file, demonstrating the correct commenting and spacing for the @implementation of an interface. It also includes the reference implementations for important methods like getters and setters, init, and dealloc. 
 //
 //  GTMFoo.m
 //  FooProject
 //
 //  Created by Greg Miller on 6/13/08.
 //  Copyright 2008 Google, Inc. All rights reserved.
 //

 #import "GTMFoo.h"


 @implementation GTMFoo

 + (id)fooWithString:(NSString *)string {
   return [[[self alloc] initWithString:string] autorelease];
 }

 // Must always override super's designated initializer.
 - (id)init {
   return [self initWithString:nil];
 }

 - (id)initWithString:(NSString *)string {
   if ((self = [super init])) {
     foo_ = [string copy];
     bar_ = [[NSString alloc] initWithFormat:@"hi %d", 3];
   }
   return self;  
 }

 - (void)dealloc {
   [foo_ release];
   [bar_ release];
   [super dealloc];
 }

 - (NSString *)foo {
   return foo_;
 }

 - (void)setFoo:(NSString *)newFoo {
   [foo_ autorelease];
   foo_ = [newFoo copy];  
 }

 - (BOOL)doWorkWithString:(NSString *)blah {
   // ...
   return NO;
 }

 @end

Blank lines before and after @interface, @implementation, and @end are optional. If your @interface declares instance variables, as most do, any blank line should come after the closing brace (}). 

Unless an interface or implementation is very short, such as when declaring a handful of private methods or a bridge class, adding blank lines usually helps readability.