There are many free Rexx interpreters available, for a wide variety of operating systems. They include--
Regina -- all operating systems (see
www.rexxla.org)
BRexx -- esp good for small systems,
runs native on Windows CE
Rexx/imc -- optimized for Linux/Unix/BSD
Reginald -- Regina extended and optimized for
Windows (includes many tools)
Object Rexx -- as in your post
roo! -- a competing object-oriented Rexx
r4 -- another Rexx for Windows plus tools
NetRexx -- Rexx for the Java environment (JVM)
Rexx for Palm OS -- program your Palm Pilot w/ Rexx
Do a "google" on any of these interpreter names to download the products. There are many dozens of interfaces and tools that work with these products.
50% of Rexx use is in the USA, 10% in the UK, 40% in many other countries.
Since going open source and gaining an ANSI standard....
Rexx is neither a "mainframe language" nor is it dead!
Happy scripting!