Rules

The following list gives an overview of which rights the PHP project reserves for itself, when choosing names for new internal identifiers. The definitive guide is the official » PHP coding standards:

• PHP owns the top-level namespace but tries to find decent descriptive names and avoid any obvious clashes.

• Function names use underscores between words, class names use PascalCase, and method names use camelCase.

• PHP will prefix any global symbols of an extension with the name of the extension. (In the past, there have been numerous exceptions to this rule, so some existing names are not prefixed.) Examples:

  • curl_exec()

  • mysqli_query()

  • PREG_SPLIT_DELIM_CAPTURE

  • new DOMDocument()

  • strpos() (example of a past mistake)

  • new SplFileObject()

• Iterators and Exceptions are however simply postfixed with "Iterator" and "Exception." Examples:

  • ArrayIterator

  • LogicException

• PHP reserves all symbols starting with __ as magical. It is recommended not to create symbols starting with __ in PHP, unless the intent is to use documented magical functionality. Examples:

  • __get()

  • __construct()