REXX - sgml/signature GitHub Wiki

# Implementation Type License GitHub Presence Interpreter Differences vs. IBM CMS Rexx First Release Most Recent Release
1 ooRexx Open Source CPL oorexx/oorexx Adds object-oriented features, class-based dispatch, and method overloading 2005 2025-05-02
2 Regina Open Source LGPL MarkHessling/Regina-REXX Classic Rexx syntax; portable; adds POSIX extensions and file I/O enhancements 1992 2024 (v3.9.5)
3 REXX/imc Open Source BSD-like RexxLA/rexx-repository Lightweight; minimal deviation; lacks full CMS system integration ~1990s ~2000s (archived)
4 BREXX Open Source GPL VVlachoudis/brexx Designed for embedded use; simplified parsing and reduced memory footprint ~1990s 2024 (MVS V2R5M3)
5 Compact Rexx (CRX) Open Source Public Domain RexxLA/rexx-repository Minimal interpreter; omits advanced I/O and error handling features ~1990s 2024 (MVP nearing)
6 IBM TSO/E REXX Closed Source Proprietary (IBM) Tailored for z/OS; includes TSO command integration and system services 1984 Active (z/OS updates)
7 IBM CMS REXX Closed Source Proprietary (IBM) Oldest interpreter; baseline for syntax, error handling, and control structures 1983 Legacy maintained
8 Personal REXX Closed Source Proprietary (Quercus) DOS/Windows adaptation; adds GUI integration and command-line enhancements 1985 ~2000 (discontinued)
9 SAA REXX Closed Source Proprietary (IBM) Part of IBM’s enterprise suite; includes dialog manager and cross-platform hooks ~1987 ~1990s (retired)
10 KEXX Closed Source Proprietary (Mansfield) Macro-oriented; embedded in KEDIT; limited external I/O and system calls ~1989 ~2000s (last update)

References