Appendix D. REXX Versions.

REXX was first introduced in VM/SP Release 3 (January 14, 1983).  That first was numbered 3.20.  But, Mike Cowlishaw, the inventor of REXX set his first steps back in March 1979 and the first releases were available internally within IBM much earlier.

A bit of history.

This discussion was held in the REXX forum in March 1993, we reproduce it here as you may find it amusing :

  ----- REXX FORUM appended at 14:07:21 on 94/03/20 GMT -----
  Subject: A milestone

  For those collectors of dates and events .. REXX is 15 years old,
  today.  Still an adolescent .. with much to look forward to.

  Mike Cowlishaw
  ----- REXX FORUM appended at 17:17:38 on 94/03/22 GMT -----
  Out of curiosity, what happened on its date of birth?  Did you wake up
  and think to yourself, "I must write a spiffy new language today" ?

  Steve Swift
  ----- REXX FORUM appended at 17:25:57 on 94/03/22 GMT -----
  No, I woke up (at about 03:15) and designed the language while tossing
  and turning for the next few hours .. then wrote down (typed in) the
  specification from memory that evening after work-for-the-day was
  over.  No home terminals those days...

  Mike Cowlishaw
  ----- REXX FORUM appended at 17:49:52 on 94/03/22 GMT -----
  Geez.    And here I thought it was going to be something impressive....

  15 years, huh?  It's getting close to the age where it will learn
  drive and leave home....   ;-)    (I hope not!)

  Alan Altmark  --  VM/ESA System Test  --  Glendale Programming Lab
  ----- REXX FORUM appended at 10:41:04 on 94/03/23 GMT ----
  In '79, 3:15am was the time I would go to bed (*)!!! Now I understand
  why I never invented Rexx :-)

  (*) In '92/93, despite the help of my daughter Marie, waking up at
  3:15 didn't have any results either.   I must be doomed :-)
  ----- REXX FORUM appended at 12:06:06 on 94/03/23 GMT ----
  Simple as that, eh ?  I look forward to insomnia, followed by fame.

  Steve Hayes                         ISL SD VM Systems Support, Sudbury

This was back in 1993, REXX now is really an adult...

Version table.

The PARSE VERSION statement returns something like this :

         REXX370 4.00 01 May 1993

Next table summarizes the different REXX versions on different platforms.  For some entries we couldn't find an accurate value, so we left them blank.

Platform	Keyword	Level	Date
CMS
VM/SP Rel 5.0	REXX370	3.40	17 Jan 1984
VM/SP Rel 6.0	REXX370	3.45
VM/SP Rel 6.0 with SPE	REXX370	3.46	31 May 1988
VM/ESA Rel 2.0	REXX370	3.48	01 May 1992
VM/ESA Rel 2.1	REXXSAA	4.00	01 May 1993
VM/ESA Rel 2.1.0	REXX370	4.00	01 May 1993
VM/ESA Rel 2.2.0	REXX370	4.01	20 Dec 1996
VM/ESA Rel 2.3.0	REXX370	4.01	20 Dec 1996
VM/ESA Rel 2.4.0	REXX370	4.02	01 Dec 1998
CMS REXX Compiler	REXXC370	3.46	30 Jun 1989
REXX/370 Compiler R2	REXXC370	3.48	28 May 1993
TSO/E Version 2
original shipment	REXX370	3.45
with SPE	REXX370	3.46	31 May 1988
TSO/E V2.4	REXX370	3.48	01 May 1992
OS/2 V2	REXXSAA	4.00	24 Oct 1997
Windows Object Rexx	OBJREXX	6.00	19 Nov 1998
OS/400	REXXSAA	3.48	21 Aug 1990

Notes:

1. A date in the table indicates an announcement or shipment implementation.
2. New releases of REXX implementations will, in general, implement the highest language level at the time of the announcement.  OS/400 is an exception: REXX File I/O is not supported.
3. Some of the language elements may have been available earlier, especially in CMS, in the form of function packages, sometimes with different semantics.
4. Object REXX is now available on many platforms, such as OS/2, Windows 95/98, Windows NT, Linux, etc.  REXX implementations can also be found from other software vendors.  We don't have values for all these versions.

Version features

These were the additions over time for the different REXX levels:

Level 3.40 Base is SAA Procedures Language Level 1 being a (rather comprehensive) subset of REXX as supported by CMS Release 5 System Product Interpreter.

Level 3.45

• added built-in functions: DIGITS(), FORM(), FUZZ(), WORDPOS()
• added DBCS (Double Byte Character Set) built-in functions
• added VALUE to numeric form
• added [NO]EXMODE to OPTIONS for DBCS handling
• added FAILURE condition to SIGNAL and TRACE
• added NOMATCH option to VERIFY()
• added Basedate and Normal to DATE()
• extend FORMAT() to replace E+00 by blanks if appropriate
• added Civil and Normal options to TIME()
• added strict comparison operators (<< >> <<= >>= \<< \>>)
• added backslash (\) as synonym/replacement for not (¬) character

All the following is not part of SAA Procedures Language.  It is still supported in VM and MVS implementations.  REXX OS/2 is the first implementation that really takes them out.

• deleted dollar, at hash, cent from symbol character set
• deleted Julian and Century options from DATE()
• deleted UPPER instruction (use TRANSLATE() instead)
• deleted EXTERNALS(), JUSTIFY(), LINSIZE(), USERID()
• deleted FIND() and INDEX(), use WORDPOS() or POS() instead.

Level 3.46

• added CALL ON|OFF for Error, Failure and Halt conditions
• added CALL or SIGNAL ON ... NAME trapname
• added CONDITION() built-in function
• increased number of arguments for CALL from 9 to 20.
• improved precision of exponentiation and integer division/remainder

Level 3.48

• added binary literals (e.g. '11001001'B for 'C9'X)
• added B2X() and X2B()
• added 'subsidiary' namelist to DROP and PROCEDURE EXPOSE, such as:

       a='AA BB CC'
       DROP (a)   /* is the same as DROP AA BB CC */
       PROCEDURE EXPOSE x (a)   /* exposes x, a, aa, bb and cc */
  

• added optional arguments newvalue and selector to VALUE()
• added prefix to variable patterns +(u), -(v), =(w) and '=' (for consistency) to positional patterns
• added system exits
• added requirement for righthand-side expression for assignment instruction
• removed SCAN option from TRACE instruction
• enhanced VALUE() built-in function with the SEToption and external variables
• all math built-in functions now normalize before use.

Level 3.50

This is the level corresponding to the REXX Handbook of Mike Cowlishaw, edition 1985.

Level 4.00

This is the level corresponding to the REXX Handbook of Mike Cowlishaw, edition 1990.

• added CHARIN(), CHAROUT(), CHARS(), LINEIN(), LINEOUT(), LINES(), STREAM() I/O functions.
• added LINEIN to PARSE
• added NOTREADY to CALL|SIGNAL ON|OFF

Level 4.01

The DATE() function is enhanced to support the Year 2000 century.  For more information, consult the Help, or alternatively, have a look at Handling DATES with REXX, an article that gives plenty of coding examples for working with dates.

Portability remarks.

• The backslash (\) will be the not-sign across all platforms.  It was not supported in VM/SP Release 5 and VM/XA. 

  <> is safe for not equal across all platforms

  >= can be used instead of ¬<

• Not-sign (¬) is also supported across all platforms.
  The problem is that upload/download utilities do usually not properly translate this character.
• PARSE NUMERIC is not supported.  The built-in functions DIGITS(), FORM() and FUZZ() can be used.
• Only PARSE [UPPER] ARG or ARG may contain a comma (,) in the template
• Literal strings must be completely on one line

      /* instead of */  v='first part
                           and second part of string'
      /* use this : */  v='first part',
                          'and second part of string'
      /* or this  : */  v='first pa'||,
                          'rt and second part of string'
  

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