Summary

• Title: PEAR2 Class Naming Conventions
• Version: 0.1.0
• Status: Draft
• Type: Informative Document
• Wiki link: http://wiki.php.net/pear/rfc/PEAR2_Class_Naming

• Name: Chuck Burgess
• Name: (second author needed)
• Email: pear-group@php.net

• This RFC is under the BSD License

• Currently only pear-group; future is pear-devhttp://news.php.net/php.pear.dev

With the introduction of namespaces in PHP 5.3, the PEAR1 rule of Package_Subpackage_ClassName naming (for creating pseudo-namespacing) is no longer necessary. Package naming rules will be set by the PEAR2_Naming_Standards RFC, whereas class naming rules are addressed here in this RFC.

The naming of individual classes retains these PEAR1 rules:

• Start with capital letter, e.g. class Foo {}
• CamelCase for multi-worded class names, e.g. class FooBarBaz {}
• Abbreviations only start with capital letter, e.g. class MrClean {}
• Acronyms should be fully capitalized, e.g. class PEARTree {}

New guidelines for PEAR2:

• syntax/scope hints that are desired to be in the class name should be suffixed rather than prefixed, e.g. abstract class FooAbstract {}
  • such suffixing is not preferred, but neither is it outlawed

• there has been some discussion/debate around various forms of “Hungarian Notation” in class naming, particularly for Abstract and Interface classes

Initial rules and guidelines:

• no suffix for an Abstract or Interface class name is necessary, nor is it preferred
  • attempts to misuse abstract classes and interfaces in userspace code will be caught by PHP anyway
  • any extra naming is effectively just for code readers to shortcut/avoid reading the code documentation, which isn't a best practice to promote
• any extra naming should be a full legible word, not a cryptic letter/abbreviation (e.g. FooAbst, FooA)
  • this follows other well-known conventions (e.g. Java)
• an “Abstract” suffix is tolerable, e.g. abstract class FooAbstract {}, though neither necessary nor preferred
  • having it suffixed makes it work better with IDE's autocompletion... otherwise, you'll always find yourself typing the full “Abstract” word just to reach the next character in the class name
• an “Interface” suffix should not be used at all, as usage of “interface PublishableInterface {}” as “class Publisher implements PublishableInterface {}” seems less readable.

• PEAR1 Coding Standards for Class Naming -- http://pear.php.net/manual/en/standards.naming.php
• Weierophinney's original post about potential naming conflicts once Namespaces arrive -- http://weierophinney.net/matthew/archives/181-Migrating-OOP-Libraries-and-Frameworks-to-PHP-5.3.html