This brief article answers these questions. The goal is to get you quickly “up to speed” on today’s Rexx. You can get more information or download anything mentioned in this article from the comprehensive web site www.RexxInfo.org .
Before we start, let’s discuss why this matters. Rexx is well known as a scripting language that combines power and ease of use. It’s good for applications programming and issuing operating system commands. The language is especially noted for its string processing power, associative arrays, and object programming extensions.
A big benefit to Rexx is that it runs on virtually all operating systems and platforms. This means that —
- Your Rexx programming skills are transferrable across platforms
- Your Rexx scripts are portable
Rexx integrates OS/2 and eCS with disparate systems. Whether you’re working in a multiple-platform environment or migrating applications between them, Rexx is a useful tool.
To illustrate Rexx’s reach, here are the free Rexx interpreters and where they run —
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The chart shows that Rexx comes in three major varieties —
- Procedural or “classic” Rexx
- Object-oriented Rexx
- Java-compatible NetRexx
All the Rexx interpreters except NetRexx meet the international Rexx language standard, called TRL-2. This makes for portable code and ensures your skills are transferrable, too.
The two object-oriented Rexx interpreters are both true supersets of classic procedural Rexx. Any classic Rexx program runs under them without alteration. This retains the value of legacy Rexx code.
This also allows you to easily learn object-oriented programming. Just program procedural Rexx and add object-oriented features as you learn them. Object-oriented Rexx’s backward-compatibility with classic procedural Rexx is a real benefit.
Open Object Rexx is the new name for the Object REXX product IBM developed in the mid-1990s. IBM open-sourced the product and gave it over to the Rexx Language Association to enhance and maintain in December of 2004. The Rexx Language Association has since come out with their newest version, 3.1. Open Object Rexx is often referred to as ooRexx for short.
roo! is a totally different object-oriented Rexx available from Kilowatt Software (the same company that offers the r4 classic Rexx interpreter). roo! and Open Object Rexx differ in syntax and have entirely different class libraries. If you want to program object-oriented Rexx, you’ll want to evaluate both Open Object Rexx and roo! to see which best meets your needs.
NetRexx is the one Rexx interpreter that diverges from the Rexx language standards. It brings Rexx’s easy syntax and ease of use to the Java environment. NetRexx scripts use Java classes and can be used to create classes used by Java programs. You can develop applets, applications, servlets, and Enterprise Java beans with NetRexx. NetRexx can even generate fully-commented Java source code.
You can use NetRexx as either a complement to, or replacement for, Java programming. Intermix NetRexx and Java routines however you like in your application systems.
The three varieties of Rexx and the multiple Rexx interpreters available for most platforms gives you choices. You can select the interpreter that best needs your needs – one optimized for speed, for example, or perhaps one extended for the operating system you work on. You may prefer either a procedural interpreter or an object-oriented one. Or maybe you like to leverage Java classes through NetRexx.
The Rexx Community
Rexx’s broad reach across platforms makes for a diverse, world-wide developer community. This ensures good support. For example, there are a dozen online Rexx forums in at least five spoken languages. Some specialize in Rexx on specific platforms. Others are generic.
By last count, I know of at least 2,000 free scripts and tools for Rexx. Some of the free scripts you might use as examples for your own coding. Others you might incorporate wholesale in your programs. Many are provided as external function libraries.
The free tools interface your Rexx programs into everything – databases, graphical user interfaces, web servers, web page scripting, HTML, XML, Microsoft Office, Open Office, and the like. Rexx is widely enough used that there is a free tool available for any purpose.
For further information, visit the Rexx web site, www.RexxInfo.org . All resources at this comprehensive site are free —
- Download all Rexx interpreters
- Manuals for all Rexx interpreters
- Downloads of thousands of Rexx tools and scripts
- Tutorials
- Sample scripts
- How-to’s
- Articles and columns
- Reference material
- Access to all online Rexx forums
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Howard Fosdick is the author of the Rexx Programmers Reference (a 700-page guide to the language available at www.amazon.com/rexx ) and the webmaster for www.RexxInfo.org .
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