Execution of $instance Definition Body

This section describes when the $instance definition body is executed.

To support object properties and methods, the system generated __new() construction function will execute the code that defines object properties in the $instance definition body.

Example showing the execution of $instance definition body:

$class user: {
   $instance x: {
      write("Adding object properties...");
      x.login = "guest";
      x.password = "DontTell";
      $method x.changePassword(newPassword): {
         x.password = newPassword;
      }
   }
}

# you will see the "Adding object properties..." message
# when the following statement is executed.
u = user(); # or user.__new();

# you will see the "Adding object properties..." message again
x = user();

Last update: 2017.

Table of Contents

 About This Book

 Introduction of H Language

 Syntax

 Data Types

 Variables

 Expressions

 Statements

 "boolean" Data Type

 "integer" Data Type

 "string" Data Type

 "real" Data Type

 "array" Data Type

 Source Code Packages

Classes and Objects

 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

 Object Oriented Programming

 Inheritance - Object Attachments

 Encapsulation - Private Members

 References

 PDF Printing Version