Object REXX: Overview and Features

Object REXX: A Comprehensive Overview

Introduction

Object REXX, a successor to the classic REXX programming language, is an object-oriented scripting language initially created by IBM for the OS/2 operating system. First introduced in 1988, Object REXX builds upon the foundation of REXX, which was designed for use with IBM’s VM/SP CMS component and later extended to other platforms such as MVS, OS/2, and PC DOS. Over time, Object REXX evolved, incorporating modern programming paradigms like object-oriented programming (OOP), and eventually, the open-source variant, Open Object Rexx (ooREXX), was released to the public in 2004. Today, this language is used for a variety of applications ranging from system scripting to software development.

In this article, we delve into the history, evolution, features, and capabilities of Object REXX, highlighting its significance in both historical and modern contexts. We will also explore its relationship with other programming languages, its use cases, and its open-source implementation.

The Evolution of REXX to Object REXX

The history of REXX dates back to the early 1970s when it was originally developed by Mike Cowlishaw at IBM. The language was designed with the goal of providing a simple, high-level programming language that was easy to learn and suitable for system programming. Classic REXX was widely adopted for its ease of use, particularly in tasks like scripting, automation, and text processing.

However, as computing environments became more complex, there arose a need for more sophisticated programming languages that could better handle object-oriented programming (OOP) and other advanced paradigms. In response to this, IBM introduced Object REXX as an extension to classic REXX. Object REXX added support for objects, classes, inheritance, and encapsulation—core concepts of object-oriented programming that made it more powerful and flexible than its predecessor.

A key aspect of Object REXX is its integration with IBM’s Systems Object Model (SOM) on the OS/2 platform. SOM provided a framework for building and managing objects in a way that was well-suited to the operating system’s architecture. This made Object REXX particularly useful for creating complex, modular, and maintainable software applications. However, the language was not limited to OS/2 and could be used on other platforms, such as MVS and PC DOS.

Key Features of Object REXX

Object REXX introduces several important features and improvements over classic REXX, making it more suitable for modern software development. Some of the most notable features of Object REXX include:

1. Object-Oriented Programming Support:
   Object REXX introduces the concept of classes and objects, enabling developers to use OOP principles such as inheritance, encapsulation, and polymorphism. These features make it easier to organize and manage code, particularly for large-scale projects.

2. Multiple Inheritance via Mixins:
   Unlike some OOP languages that only support single inheritance, Object REXX allows for multiple inheritance through the use of mixin classes. Mixins enable the reuse of functionality across different classes without creating complex inheritance hierarchies.

3. SOM Integration:
   The integration with IBM’s Systems Object Model (SOM) allows Object REXX to interact with other SOM-compliant languages and libraries, making it a versatile choice for developing software in IBM’s ecosystem. However, it’s worth noting that the open-source implementation of Object REXX, ooREXX, does not include significant SOM support.

4. Extensibility:
   Object REXX supports the extension of existing classes and the creation of new classes with custom methods and attributes. This extensibility makes it suitable for a wide range of applications, from simple scripting tasks to complex enterprise-level software development.

5. Cross-Platform Support:
   While initially developed for OS/2, Object REXX and its open-source version, ooREXX, are now available for a variety of platforms, including Linux, Solaris, and Windows. This cross-platform compatibility has expanded its reach, allowing developers to use Object REXX in a diverse set of environments.

6. Scripting and Automation:
   As with classic REXX, Object REXX is well-suited for scripting and automation tasks. Its syntax is simple and easy to read, making it an ideal choice for quick development of scripts for system administration, testing, and other routine tasks.

7. Built-in Libraries and Functions:
   Object REXX comes with a rich set of built-in functions and libraries that facilitate various tasks such as string manipulation, file handling, and process control. These built-in tools reduce the need for developers to write complex code from scratch.

Open Object REXX (ooREXX)

In 2004, IBM released Object REXX as open-source software under the name Open Object Rexx (ooREXX). This release marked a significant milestone in the history of the language, as it allowed the programming community to contribute to its development and expand its use beyond the IBM ecosystem.

Open Object Rexx is available for a variety of platforms, including Linux, Solaris, and Windows. It includes many of the features of the original Object REXX but does not include certain IBM-specific components, such as full SOM support. Nevertheless, the open-source release has led to the creation of numerous tools, libraries, and applications that leverage Object REXX’s capabilities.

The open-source community has played a vital role in improving ooREXX by adding new features, fixing bugs, and ensuring that the language remains relevant in modern development environments. Developers can access the source code on GitHub, where they can contribute to ongoing development efforts and report issues.

Object REXX in Modern Development

Although Object REXX may not be as widely used as more mainstream programming languages like Python or Java, it still holds a niche position in specific domains, particularly in IBM-centric environments. Object REXX is commonly used in system administration, script development, and software testing due to its simplicity, readability, and flexibility.

One of the key strengths of Object REXX is its ability to integrate with other software components. Its support for object-oriented principles makes it well-suited for building modular, maintainable systems. In particular, its integration with IBM’s SOM framework enables Object REXX to interact seamlessly with other SOM-compliant software and libraries, making it a valuable tool in enterprise environments.

Furthermore, the open-source nature of ooREXX has made it more accessible to a wider audience. Developers working in Linux or other non-IBM platforms can now take advantage of Object REXX’s unique capabilities without being tied to IBM’s proprietary systems. The continued development of ooREXX by the open-source community ensures that the language remains relevant and adaptable to new challenges in modern software development.

Use Cases of Object REXX

Object REXX has found applications in a variety of fields, primarily due to its strong scripting capabilities, ease of use, and OOP support. Some common use cases include:

• System Administration: Object REXX is well-suited for writing scripts that automate system management tasks, such as file manipulation, user management, and service monitoring.
• Software Testing: The language’s simplicity makes it an excellent choice for writing test scripts, particularly for automated testing of other applications.
• Scripting for IBM Environments: In environments that use IBM hardware and software, Object REXX provides an effective means for creating scripts that interact with IBM’s systems and software.
• Data Processing: Object REXX’s powerful string manipulation and file handling capabilities make it a useful tool for processing large datasets and performing routine data analysis tasks.

Conclusion

Object REXX represents a significant evolution from its predecessor, classic REXX, bringing modern object-oriented programming features to a language known for its simplicity and ease of use. While it was originally designed for IBM’s OS/2 operating system, its open-source variant, ooREXX, has allowed it to extend its reach to a wider audience, including developers working on Linux, Solaris, and Windows.

Despite being overshadowed by more popular programming languages, Object REXX remains a valuable tool for specific use cases, particularly in IBM environments. Its support for object-oriented principles, along with its scripting and automation capabilities, makes it a powerful and versatile language for system administration, software testing, and other tasks. As the open-source community continues to contribute to the development of ooREXX, the language is likely to remain relevant and continue to evolve in response to the needs of modern software developers.

For more information, visit the official Open Object REXX website at www.oorexx.org or explore the language’s Wikipedia page here.