• Simple is better than complex (see "The Zen of Python")
• Use phpdoc syntax for every function you add.
• Limit lines to 78 characters
• Use the identical operator whenever possible (faster).
• Do not use magic numbers! If you spot any in the core, remove them or file a bug report!

• Use the Allman style
• Use tabs for indentation
• Do not indent functions with one tab (indent methods with one tab).
• Do not align assignment operators for multiple lines.

/**
 * Function description.
 * 
 * @param string $foo A variable.
 * @return string
 */
function fooBar($foo)
{
    if ($foo === 'bar')
    {
        $out[] = $foo;
    }
    else
    {
        $out[] = 'baz';
    }
 
    return implode('', $out);
}