On Mon, 27 Aug 2012 11:33:01 +0000, Bob Shannon wrote: > >CLIST stands for "Command List" i.e., a means to string a series of TSO >commands together. It was rudimentary. Although some improvements have been >added since its inception, it's no Rexx. > Both CLIST and CMS EXEC, but not EXEC 2 nor Rexx are so closely coupled to the terminal input routine that they are the only true script facilities, scarcely deserving of independent recognition as "languages". This results in the sometimes useful behavior that the programmer can invoke a utility (often EDIT, but not PDF nor XEDIT) and continue with inline subcommands to that utility. This is qualitatively different from *NIX here-documents or JCL SYSIN in that the status from each subcommand is available for testing in the parent script.
(Can one execute a CLIST loop from the terminal rather than from a CLIST file?) Rexx is the furthest from a true scripting language, suffering the design defect (Shmuel considers it an advantage) of allowing reference to functions prior to their definition. This would engender the misbehavior were Rexx to be used as a terminal scripting language (some programmers have tried to implement this with wrapper scripts) that a typo in a function name could cause an endless input loop as the interpreter looked ahead for the function definition. I had some conceptual difficulty when I was first learing UNIX (Bourne) shell scripting because I failed to grasp that I was communicating with the same command interpreter from the terminal as from a script file; I often wanted to use too many quotes in the latter. Rexx habit. I understand that Warnock initially envisioned PostScript as a general purpose scripting language, not merely for document rendering. In fact, SunOS 4 had a PostScript-like shell language available. It interested me because I had some knowledge of PostScript at the time. But I was never able to find its analog of the system() command, and lost interest. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
