Documentation Menu

1.5 Template Project

The Joomla! Documentation Working Group is running a project to develop detailed reference and tutorial material on Joomla! 1.5 templates.  There is a project page on the documentation wiki where you can see the work in progress and help us by contributing your knowledge.

Who's Online

We have 4 guests online

Help Site License

The Joomla! Help Site content is copyright © 2005 - 2008 by the individual contributors and can be used in accordance with the Creative Commons License, Attribution NonCommercial ShareAlike 2.5. Some parts of this website may be subject to other licenses.
Home arrow Manual arrow 10. Development Standards arrow Coding Standards

Coding Standards PDF Print E-mail

Joomla! will abide by the PEAR coding standards (http://pear.php.net/manual/en/standards.php). You can either consult them online or read them here:

PEAR Coding Standards

Indenting and Line Length

Use an indent of 4 spaces, with no tabs. If you use Emacs to edit PEAR code, you should set indent-tabs-mode to nil. Here is an example mode hook that will set up Emacs according to these guidelines (you will need to ensure that it is called when you are editing PHP files):

(defun php-mode-hook ()
  (setq tab-width 4
        c-basic-offset 4
        c-hanging-comment-ender-p nil
        indent-tabs-mode
        (not
         (and (string-match "/\\(PEAR\\|pear\\)/" (buffer-file-name))
              (string-match "\.php$" (buffer-file-name))))))

Here are vim rules for the same thing:

set expandtab
set shiftwidth=4
set softtabstop=4
set tabstop=4

It is recommended that you break lines at approximately 75-85 characters. There is no standard rule for the best way to break a line, use your judgment and, when in doubt, ask on the PEAR Quality Assurance mailing list.

Control Structures

These include if, for, while, switch, etc. Here is an example if statement, since it is the most complicated of them:

<?php
if ((condition1) || (condition2)) {
    action1;
} elseif ((condition3) && (condition4)) {
    action2;
} else {
    defaultaction;
}
?>

Control statements should have one space between the control keyword and opening parenthesis, to distinguish them from function calls.

You are strongly encouraged to always use curly braces even in situations where they are technically optional. Having them increases readability and decreases the likelihood of logic errors being introduced when new lines are added.

For switch statements:

<?php
switch (condition) {
case 1:
    action1;
    break;
case 2:
    action2;
    break;
default:
    defaultaction;
    break;
}
?>

Function Calls

Functions should be called with no spaces between the function name, the opening parenthesis, but one space between the opening parenthesis and the first parameter; spaces between commas and each parameter, and one space between the last parameter, the closing parenthesis. Here's an example:

<?php
$var = foo( $bar, $baz, $quux );
?>

As displayed above, there should be one space on either side of an equals sign used to assign the return value of a function to a variable. In the case of a block of related assignments, more space may be inserted to promote readability:

<?php
$short         = foo( $bar );
$long_variable = foo( $baz );
?>

Function Definitions

Function declarations follow the "one true brace" convention:

<?php
function fooFunction( $arg1, $arg2 = '' ){
 
    if (condition) {
        statement;
    }
    return $val;
}
?>

Arguments with default values go at the end of the argument list. Always attempt to return a meaningful value from a function if one is appropriate. Here is a slightly longer example:

<?php
function connect( &$dsn, $persistent = false ){
 
    if (is_array( $dsn )) {
        $dsninfo = &$dsn;
    } else {
        $dsninfo = DB::parseDSN( $dsn );
    }    if (!$dsninfo || !$dsninfo['phptype']) {
        return $this->raiseError();
    }    return true;
}
?>

Comments

Inline documentation for classes should follow the PHPDoc convention, similar to Javadoc. More information about PHPDoc can be found here: http://www.phpdoc.org/

See also Adding PHPDocumentor comments

Non-documentation comments are strongly encouraged. A general rule of thumb is that if you look at a section of code and think "Wow, I don't want to try and describe that", you need to comment it before you forget how it works.

C style comments (/* */) and standard C++ comments (//) are both fine. Use of Perl/shell style comments (#) is discouraged.

Including Code

Anywhere you are unconditionally including a class file, use require_once(). Anywhere you are conditionally including a class file (for example, factory methods), use include_once(). Either of these will ensure that class files are included only once. They share the same file list, so you don't need to worry about mixing them - a file included with require_once() will not be included again by include_once().

    Note: include_once() and require_once() are statements, not functions. You don't need parentheses around the filename to be included.

PHP Code Tags

Always use <?php ?> to delimit PHP code, not the <? ?> shorthand. This is required for PEAR compliance and is also the most portable way to include PHP code on differing operating systems and setups.

Header Comment Blocks

All source code files in the core PEAR distribution should contain the following comment block as the header:

<?php
/**
 * Short description for file
 *
 * Long description for file (if any)...
 *
 * PHP versions 4 and 5
 *
 * LICENSE: This source file is subject to version 3.0 of the PHP license
 * that is available through the world-wide-web at the following URI: 
 * http://www.php.net/license/3_0.txt
 * If you did not receive a copy of the PHP License and are unable to obtain it through the web,
 * please send a note to license@php.net so we can mail you a copy immediately.
 *
 * @category   CategoryName
 * @package    PackageName
 * @author     Original Author author@example.com
 * @author     Another Author another@example.com
 * @copyright  1997-2005 The PHP Group
 * @license    http://www.php.net/license/3_0.txt PHP License 3.0
 * @version    CVS: $Id:$
 * @link       http://pear.php.net/package/PackageName
 * @see        NetOther, Net_Sample::Net_Sample()
 * @since      File available since Release 1.2.0
 * @deprecated File deprecated in Release 2.0.0
 */
 
/*
 * Place includes, constant defines and $_GLOBAL settings here.
 * Make sure they have appropriate docblocks to avoid phpDocumentor
 * construing they are documented by the page-level docblock.
 */
 
/**
 * Short description for class
 *
 * Long description for class (if any)...
 *
 * @category   CategoryName
 * @package    PackageName
 * @author     Original Author author@example.com
 * @author     Another Author another@example.com
 * @copyright  1997-2005 The PHP Group
 * @license    http://www.php.net/license/3_0.txt PHP License 3.0
 * @version    Release: @package_version@
 * @link       http://pear.php.net/package/PackageName
 * @see        NetOther, Net_Sample::Net_Sample()
 * @since      Class available since Release 1.2.0
 * @deprecated Class deprecated in Release 2.0.0
 */
 
class foo {
 
}
?>

There's no hard rule to determine when a new code contributor should be added to the list of authors for a given source file. In general, their changes should fall into the "substantial" category (meaning somewhere around 10% to 20% of code changes). Exceptions could be made for rewriting functions or contributing new logic.

Simple code reorganization or bug fixes would not justify the addition of a new individual to the list of authors.

Files not in the core PEAR repository should have a similar block stating the copyright, the license, and the authors. All files should include the modeline comments to encourage consistency.

Example URLs

Use "example.com", "example.org" and "example.net" for all example URLs and email addresses, per RFC 2606.

Naming Conventions

Classes

Classes should be given descriptive names. Avoid using abbreviations where possible. Class names should always begin with an uppercase letter. The PEAR class hierarchy is also reflected in the class name, each level of the hierarchy separated with a single underscore. Examples of good class names are:

Log  Net_Finger  HTML_Upload_Error

Functions and Methods

Functions and methods should be named using the "studly caps" style (also referred to as "bumpy case" or "camel caps"). Functions should in addition have the package name as a prefix, to avoid name collisions between packages. The initial letter of the name (after the prefix) is lowercase, and each letter that starts a new "word" is capitalized. Some examples:

connect()  getData()  buildSomeWidget()  XML_RPC_serializeData()

Private class members (meaning class members that are intented to be used only from within the same class in which they are declared; PHP does not yet support truly-enforceable private namespaces) are preceded by a single underscore. For example:

_sort()  _initTree()  $this->_status

Constants

Constants should always be all-uppercase, with underscores to separate words. Prefix constant names with the uppercased name of the class/package they are used in. For example, the constants used by the DB:: package all begin with "DB_".

Global Variables

If your package needs to define global variables, their name should start with a single underscore followed by the package name and another underscore. For example, the PEAR package uses a global variable called $_PEAR_destructor_object_list.

Last Updated ( Thursday, 08 December 2005 )
 
Next >