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REXX (REstructured eXtended eXecutor) is an interpreted programming language which was developed at IBM. It is a structured high-level programming language which was designed to be both easy to learn and easy to read. Both commercial and open source interpreters for REXX are available on a wide range of computing platforms, and compilers are available for IBM mainframes. FeaturesREXX has the following characteristics and features:
REXX has just twenty-three, largely self-evident, instructions (for example, call, parse, and select) with minimal punctuation and formatting requirements. It is essentially an almost free-form language with only one data-type, the character string; this philosophy means that all data are visible (symbolic) and debugging and tracing are simplified. REXX syntax looks similar to PL/I, but has fewer notations; this makes it harder to parse (by program) but easier to use. HistoryREXX was designed and first implemented, in assembly language, as an ‘own-time’ project between 20 March 1979 and mid-1982 by Mike Cowlishaw of IBM, originally as a scripting programming language to replace the languages EXEC and EXEC 2. It was designed to be a macro or scripting language for any system. As such, REXX is considered a precursor to Tcl and Python. Over the years IBM included REXX in almost all of its operating systems (VM/CMS, VM/GCS, MVS TSO/E, AS/400, VSE/ESA, AIX, CICS/ESA, PC-DOS, and OS/2), and has made versions available for Novell NetWare, Windows, Java, and Linux. The first non-IBM version was written for PC-DOS by Charles Daney in 1984/5. Other versions have also been developed for Atari, AmigaOS, Unix (many variants), Solaris, DEC, Windows, Windows CE, PocketPC, MS-DOS, Palm OS, QNX, OS/2, Linux, BeOS, EPOC32, AtheOS, OpenVMS, OpenEdition, Macintosh, and Mac OS X. SpellingOriginally it was just called "Rex", "A Reformed EXecutor"; the extra "X" was added to avoid collisions with other products' names. The expansion of Rexx to the REstructured EXtended EXecutor is believed to be a backronym. REX was originally all uppercase because the mainframe code was uppercase oriented. The style in those days was to have all-caps names (partly because almost all code was still all-caps then). For the product it became REXX, and both editions of Mike Cowlishaw's book use all-caps. By the 1990s it was largely written Rexx or, with small caps: REXX. As of 2008, Mike Cowlishaw seems to prefer Rexx, IBM documents use REXX, and the ANSI standard uses REXX. Article source: http://en.wikipedia.org/wiki/Rexx Go back to Programming Articles home page
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