Classes and Objects

∟Classes and Objects

This chapter provides notes on classes and objects in H language.

What Is Class

What Is Object

$class Statement - Create New Classes

Class Variables and Functions

Execution of $class Definition Body

__new() - Object Constructor Function

$instance Statement - Define Instance Template

Execution of $instance Definition Body

Access Object Properties

$method Statement - Define Object Method

Access Object Methods

_first() Method - Object Initialization

Access Class Variables from Object Methods

__delete() - Object Destructor Method

$delete Statement - Delete Objects

_last() Method - Object Cleanup

Takeaways:

A class is a data type that defines a group of data objects with the same list of properties and methods
An object, also called instance, is a data object of a specific class. It has the same list of properties and methods as all other objects created by the same class.
$class statement is for creating new classes.
A class can have class variables and functions to support object properties and methods.
The $class definition body is executed, when the $class statement is executed.
Object constructor function, __new(), is a built-in special class function to create new objects.
class_name() is shorthand version of class_name.__new().
The $instance statement is for defining instance (or object) properties and methods within the class definition body.
The $instance definition body is executed, each time when the __new() function is called.
The $method statement is for defining object (or instance) methods within the instance template definition body.
Once an object is created, you can use the dot (.) expression to access its properties and methods.
The _first() method is for object initialization during the new object construction process.
Object destructor method, __delete(), is a built-in special object method to delete an object.
The $delete statement is equivalent of calling the __delete method.
The _last() method is for object cleanup during the object destruction process.