path: root/pear/CODING_STANDARDS

===========================================================================
|| PEAR Coding Standards                                                 ||
===========================================================================

$Id$

-------------
[1] Indenting
=============

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 tabstop=4 


----------------------
[2] Control Structures
======================

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

  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:

  switch (condition) {
  case 1:
      action1;
      break;

  case 2:
      action2;
      break;

  default:
      defaultaction;
      break;

  }


------------------
[3] Function Calls
==================

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

  $var = foo($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:

  $short         = foo($bar);
  $long_variable = foo($baz);


------------------------
[4] Function Definitions
========================

Function declaractions follow the "one true brace" convention:

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:

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;
}

Functions should be named using the "studly caps" style (also referred to as
"bumpy case" or "camel caps").  The initial letter of the name is lowercase,
and each letter that starts a new "word" is capitalized.  Some examples:

    connect()       getData()       buildSomeWidget()

Private class members (meaning class members that an 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 preceeded by a single
underscore.  For example:

    _sort()         _initTree()     $_status


------------
[5] Comments
============

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

    http://www.phpdoc.de/

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.


------------------
[6] 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.


-----------------
[7] 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.


-------------------------
[8] Header Comment Blocks
=========================

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

/* vim: set expandtab tabstop=4 shiftwidth=4: */
// +----------------------------------------------------------------------+
// | PHP version 4.0                                                      |
// +----------------------------------------------------------------------+
// | Copyright (c) 1997, 1998, 1999, 2000, 2001 The PHP Group             |
// +----------------------------------------------------------------------+
// | This source file is subject to version 2.0 of the PHP license,       |
// | that is bundled with this package in the file LICENSE, and is        |
// | available at through the world-wide-web at                           |
// | http://www.php.net/license/2_02.txt.                                 |
// | If you did not receive a copy of the PHP license and are unable to   |
// | obtain it through the world-wide-web, please send a note to          |
// | license@php.net so we can mail you a copy immediately.               |
// +----------------------------------------------------------------------+
// | Authors: Original Author <author@example.com>                        |
// |          Your Name <you@example.com>                                 |
// +----------------------------------------------------------------------+
//
// $Id$

There's no hard rule to determine when a new code contributer 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.


------------
[9] CVS Tags
============

Include the <dollar>Id CVS vendor tag in each file.  As each
file is edited, add this tag if it's not yet present (or replace existing
forms such as "Last Modified:", etc.).

[NOTE: we have a custom $Horde tag in Horde cvs to track our versions 
seperately; we could do the same and make a $PEAR tag, that would remain even 
if PEAR files were put into another source control system, etc...]


-----------------
[10] Example URLs
=================

Use "example.com" for all example URLs, per RFC 2606.


---------------------
[11] Naming Constants
=====================

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

True and false are built in to the php language and behave like
constants, but should be written in lowercase to distinguish them from
user-defined constants.