Core framework code style

https://github.com/yiisoft/yii/wiki/Core-framework-code-style

The following code style is used for Yii 1.x development. If you want to pull-request code into the core, consider using it. We aren't forcing you to use this code style for your application. Feel free to choose what suits you better.

There is a CodeSniffer ruleset for this standard developed by @Ardem: https://github.com/Ardem/yii-coding-standard

1. Overview

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• Files MUST use only <?php tags.
• Files MUST use only UTF-8 without BOM for PHP code.
• Code MUST use tabs for indenting, not spaces.
• Class names MUST be declared in StudlyCaps.
• Class constants MUST be declared in all upper case with underscore separators.
• Method names MUST be declared in camelCase.
• Property names MUST be declared in camelCase.
• Property names MUST start with an initial underscore if they are private.
• Indentation uses Allman style with single line expressions on next line, without braces.
• Always elseif instead of else if.

2. Files

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2.1. PHP Tags

PHP code MUST use the long <?php ?> tags; it MUST NOT use the other tag variations.

2.2. Character Encoding

PHP code MUST use only UTF-8 without BOM.

3. Class Names

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Class names MUST be declared in StudlyCaps. Core classes should be prefixed with C. For example, CController, CWidget. Application and extension classes should not use C as prefix. For extensions it's common to use E.

4. Classes

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The term "class" refers to all classes and interfaces here.

4.1. Constants

Class constants MUST be declared in all upper case with underscore separators. For example:

<?php
class Foo
{
    const VERSION='1.0';
    const DATE_APPROVED='2012-06-01';
}

4.2. Properties

Property names MUST be declared in camelCase. Property names MUST start with an initial underscore if they are private.

For example:

<?php
class Foo
{
    public $publicProp;
    protected $protectedProp;
    private $_privateProp;
}

4.3. Methods

Method names MUST be declared in camelCase().

4.4 Doc blocks

@param, @var, @property and @return must declare types as boolean, integer, string, array or null. You can use a class names as well such as CModel or CActiveRecord. For a typed arrays use ClassName[].

4.5 Constructors

• __construct should be used instead of PHP 4 style constructors.
• When instantiating class it should be new MyClass(); instead of new MyClass;.