I've been writing and invoking macros since Assembler D (DOS/360 1968) and I don't believe that duplicated keyword parameters were ever accepted. I could be wrong.
Somehow for a parameter *file* like PARMLIB I'm willing to accept that duplicates should be accepted and that the last value should prevail. (If the first value prevails, then the processing software must "know" that the value has already been provided and should diagnose the duplication.) You should be able to override the values in parmfile.one by appending parmfile.two. It's like "real life." In a conversation or an e-mail I might at first say "see you next Tuesday at 10" and a little later say "I might be running late, so make it between 10 and 11." You would not ignore the latter value because I had already provided an earlier value. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Vernooij, CP - SPLXM Sent: Tuesday, July 06, 2010 7:33 AM To: [email protected] Subject: Re: Amusing JCL Oddity "Paul Gilmartin" <[email protected]> wrote in message news:<listserv%[email protected]>... > It's a prevalent habit of coders to exploit naive parameter list > parsers by writing scripts which simply append overriding key/value > pairs to the end of a default parameter string. > > Historically, Linkage Editor and Assembler H permitted this in PARM > strings, allowing the later value of the keyword to prevail. With > the advent of Binder (IIRC; perhaps it was HLASM; perhaps both), > duplicate keys in the PARM string were treated as errors. This was > swiftly reverted to the earlier behavior, likely by APAR. > > But JCL differs from the mode in using the earlier value rather than > the later. > > -- gil > And then there is also the parsing of parmlib members, where a parameter can occur multiple times in one member or multiple times in several sequentially processed members (IEASYSxx). The rules are as diverse as possible: select the first value, select the last value, add the values of all occurances of the parameter or not accept multiple occurances of a parameter. So you are subjected to the applicatin coder's view on what is desirable. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
