Feeds

Rexx - the practical programming language

Another legacy language which still has supporters today

7 Elements of Radically Simple OS Migration

Comment What is it with old languages? I only have to mention REXX while talking about Mumps and someone (the sort of person who remembers that the original, circa 1970-80, MUMPS was actually a O/S, language and integrated DBMS all in one – I can relate to that, perhaps why I like iSeries too) jumps up to say how much they liked it.

I liked REXX partly because (like many other much-loved languages), it actually had a personality attached to it – Mike Cowlishaw.

REXX was first developed by Mike between 1979-82 at IBM Hursley in the UK and the T. J. Watson Research Centre in the USA. In 1987, it became the Procedures Language for IBM’s System application Architecture (SAA) and in 1989 IBM Austria developed a REXX compiler.

Back when I first met REXX, you could even chat with Mike on the UK-based CIX conferencing system (another legacy that is still useful).

Mike valued user feedback. As he says (in “The REXX Language, a practical approach to programming”, M.F. Cowlishaw, Prentice Hall, ISBN 0-13-779067-8, which unfortunately seems to be out of print - the Rexx Programmer's Reference by Howard Fosdick is a possible alternative): "The language user is usually right ... It is impossible to overestimate the value of the direct feedback from users that was available while REXX was being designed”.

So, given that we had Visual Basic and MSDOS macros and so on when I met it, just what was so good about programming REXX? Back when Visual Basic books were 5cm thick and you argued around the coffee machine about what some lump of VB code actually did, REXX was powerful, compact and readable - and available as Personal REXX on the PC. In a language described in a 1 cm slim book (op. cit.), you could write comprehensible, properly-structured programs invoking all the power of the utilities/commands on an IBM mainframe.

Rather than trying to do everything itself, it was designed to encourage linking to external environments and reuse of the facilities there. Like Visual Basic on Windows (REXX was also designed as an interpreted language), perhaps, but REXX was fully-designed from scratch, it didn't just grow as people came up with neat ideas (perhaps VB.NET, after all these years, is a better comparison). I suspect that IBM still has a lot of REXX legacy code, since it was extensively used for tailoring the CMS component of IBM VM/SP - originally a “stopgap” Virtual Machine mainframe operating system that eventually made it to the strategic mainstream.

REXX was also wonderful for string handling – except for one foible – converting text to upper-case was dead easy, as I remember it, because that was what IBM big iron expected, but lower or mixed case was trickier. Still, its features for parsing input for processing according to a defined pattern were pretty neat back then.

No doubt they seem less neat today, when sophisticated scripting languages are commonplace, but REXX is not dead – neither has it stood still (there’s an open source community here and it is interesting that uppercase REXX itself seems to have transmogrified into mixed case Rexx).

Object Rexx is alive and well and there's a brief introduction to it here. If you want to learn more about its features (such as accurate decimal arithmetic for business calculations instead of binary floating-point arithmetic) visit the OO Rexx site. ®

David Norfolk is the author of IT Governance, published by Thorogood. More details here.

Endpoint data privacy in the cloud is easier than you think

More from The Register

next story
PEAK LANDFILL: Why tablet gloom is good news for Windows users
Sinofsky's hybrid strategy looks dafter than ever
Leaked Windows Phone 8.1 Update specs tease details of Nokia's next mobes
New screen sizes, dual SIMs, voice over LTE, and more
POW! Apple smites Macbook Air EFI firmware update borkage
Fruity firm provides digital balm for furious fanbois
Call off the firing squad: HP grants stay of execution to OpenVMS
Startup to take over support for today's Itaniums and beyond
Fiendishly complex password app extension ships for iOS 8
Just slip it in, won't hurt a bit, 1Password makers urge devs
Mozilla keeps its Beard, hopes anti-gay marriage troubles are now over
Plenty on new CEO's todo list – starting with Firefox's slipping grasp
Apple: We'll unleash OS X Yosemite beta on the MASSES on 24 July
Starting today, regular fanbois will be guinea pigs, it tells Reg
Another day, another Firefox: Version 31 is upon us ALREADY
Web devs, Mozilla really wants you to like this one
prev story

Whitepapers

7 Elements of Radically Simple OS Migration
Avoid the typical headaches of OS migration during your next project by learning about 7 elements of radically simple OS migration.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Solving today's distributed Big Data backup challenges
Enable IT efficiency and allow a firm to access and reuse corporate information for competitive advantage, ultimately changing business outcomes.
A new approach to endpoint data protection
What is the best way to ensure comprehensive visibility, management, and control of information on both company-owned and employee-owned devices?