# Naming Conventions

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HTML Purifier End-User Documentation

The classes in this library follow a few naming conventions, which may help you find the correct functionality more quickly. Here they are:

All classes occupy the HTMLPurifier pseudo-namespace.
  This means that all classes are prefixed with HTMLPurifier_. As such, all names under HTMLPurifier_ are reserved. I recommend that you use the name HTMLPurifierX_YourName_ClassName, especially if you want to take advantage of HTMLPurifier_ConfigDef.
All classes correspond to their path if library/ was in the include path
  HTMLPurifier_AttrDef is located at HTMLPurifier/AttrDef.php; replace underscores with slashes and append .php and you'll have the location of the class.
Harness and Test are reserved class names for unit tests
  The suffix `Test` indicates that the class is a subclass of UnitTestCase (of the Simpletest library) and is testable. "Harness" indicates a subclass of UnitTestCase that is not meant to be run but to be extended into concrete test cases and contains custom test methods (i.e. assert*())
Class names do not necessarily represent inheritance hierarchies
  While we try to reflect inheritance in naming to some extent, it is not guaranteed (for instance, none of the classes inherit from HTMLPurifier, the base class). However, all class files have the require_once declarations to whichever classes they are tightly coupled to.
Strategy has a meaning different from the Gang of Four pattern
  In Design Patterns, the Gang of Four describes a Strategy object as encapsulating an algorithm so that they can be switched at run-time. While our strategies are indeed algorithms, they are not meant to be substituted: all must be present in order for proper functioning.
Abbreviations are avoided
  We try to avoid abbreviations as much as possible, but in some cases, abbreviated version is more readable than the full version. Here, we list common abbreviations:
  - Attr to Attributes (note that it is plural, i.e. `$attr = array()`)
  - Def to Definition
  - `$ret` is the value to be returned in a function
Ambiguity concerning the definition of Def/Definition
  While a definition normally defines the structure/acceptable values of an entity, most of the definitions in this application also attempt to validate and fix the value. I am unsure of a better name, as "Validator" would exclude fixing the value, "Fixer" doesn't invoke the proper image of "fixing" something, and "ValidatorFixer" is too long! Some other suggestions were "Handler", "Reference", "Check", "Fix", "Repair" and "Heal".
Transform not Transformer
  Transform is both a noun and a verb, and thus we define a "Transform" as something that "transforms," leaving "Transformer" (which sounds like an electrical device/robot toy).