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 » CODING STANDARDS:
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PHP owns the top-level namespace but tries to find decent descriptive names and avoid any obvious clashes.
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Function names use underscores between words, while class names use the camel case rule (there are some exceptions for older classes and functions).
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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.) Examples:
PREG_SPLIT_DELIM_CAPTURE
new DOMDocument()
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strpos() (example of a past mistake)
new SplFileObject()
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Iterators and Exceptions are however simply postfixed with "Iterator" and "Exception." Examples:
ArrayIterator
LogicException
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PHP reserves all symbols starting with __ as magical. It is recommended that you do not create symbols starting with __ in PHP unless you want to use documented magical functionality. Examples:
__get()
__autoload()
Коментарии
Angst relief for Drupal apprentices:remember that the prefix (and suffix) for PHP magical symbols
is two (2) underscores. The Drupal coding standard is one underscore
for some types of programmer-created identifiers.