[Default] On 6 Jun 2020 10:53:44 -0700, in bit.listserv.ibm-main robhbrid...@gmail.com (Bob Bridges) wrote:
>Oh, you need an END-IF even for a single-statement IF? I forgot; I've been >thinking in REXX too long. In that case you're close; I guess I really meant In your example the END-IF is not needed. However beginning with VS COBOL IIV4 (1985 standard) it became better practice to eliminate all but the last period in a paragraph and terminate all conditional with end statements such as END-IF. With Enterprise COBOL 5.2 and later (2002 Standard) the 1050-EXIT paragraph could be eliminated and the GO TOs replaced with EXIT PARAGRAPH. This allow simpler code generation for the PERFORM and the PERFORMed paragraph be moved inline to in effect replace the PERFORM statement. Also look up inline PERFORMs. In general, because of code optimization starting with VS COBOL II release 4 (1985 standard) GO TO became a bad idea. Clark Morris > > PERFORM 1050-LOOP THRU 1050-EXIT VARYING JC FROM 1 BY 1 TO 99 > > 1050-LOOP. > IF X > 999 GOTO 1050-EXIT END-IF. > IF FIRST-NAME = "ROBERT" GOTO 1050-EXIT END-IF. > IF TYPE <> 195 GOTO 1050-EXIT END-IF. > IF NOT SO-ON GOTO 1050-EXIT END-IF. > IF NOT SO-FORTH GOTO 1050-EXIT END-IF. > [do such and such] > 1050-EXIT. > >I'm happy to hear someone else admit that a GOTO is conceivable under ~any~ >circumstances. In my old shop I argued for GOTOs in three very strictly >limited circumstances, the other two being end-of-section and end-of-program. >Some languages allow for this by including some flavor of "leave" statement; >all I want to do with a GOTO is to simulate that part of structured >programming. But at the particular shop I have in mind, none of that could be >contemplated, because all GOTOs are evil. > >--- >Bob Bridges, robhbrid...@gmail.com, cell 336 382-7313 > >/* Law #21 of combat operations: The important things are always simple; the >simple things are always hard. */ > >-----Original Message----- >From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On >Behalf Of Joe Monk >Sent: Saturday, June 6, 2020 04:49 > >I think what you mean is this: > >PERFORM 1050-LOOP THRU 1059-EXIT VARYING JC FROM 1 BY 1 UNTIL JC = 99 >END-PERFORM > > 1050-LOOP. > IF FIRST-NAME NOT = "ROBERT" > GO TO 1059-EXIT > END-IF > IF TYPE NOT = 195 > GO TO 1059-EXIT > END-IF > IF NOT SO-ON > GO TO 1059-EXIT > END-IF > IF NOT SO-FORTH > GO TO 1059-EXIT > END-IF > PERFORM 1050-SUCH-AND-SUCH END-PERFORM > > 1059-EXIT. > EXIT. > >In structured programming, it is perfectly acceptable to use GO TO within a >paragraph. It is NOT acceptable to use GO TO outside of a paragraph. > >--- On Sat, Jun 6, 2020 at 12:42 AM Bob Bridges <robhbrid...@gmail.com> wrote: >> I realize this is a bit of a change in subject (and it's not as if we need >> yet another one), but I avoid this construction. My phobia is based on an >> extreme example: In their zeal never to use GOTOs, I've frequently seen >> programmers write paragraphs like this: >> >> PERFORM 1050-LOOP VARYING JC FROM 1 BY 1 TO 99 >> >> 1050-LOOP. >> IF X < 1000 >> IF FIRST-NAME NOT = "ROBERT" >> IF TYPE = 195 >> IF SO-ON >> IF SO-FORTH >> EXECUTE 1050-SUCH-AND-SUCH >> END-IF >> END-IF >> END-IF >> END-IF >> END-IF >> >> Gives me a headache to try to evaluate that. Much better, in my opinion, >> to introduce ONE LOUSY "GOTO EO-PARAGRAPH" like this: >> >> PERFORM 1050-LOOP THRU 1059-LOOP VARYING JC FROM 1 BY 1 TO 99 >> >> 1050-LOOP. >> IF X > 999 GOTO 1059-LOOP. >> IF FIRST-NAME = "ROBERT" GOTO 1059-LOOP. >> IF TYPE <> 195 GOTO 1059-LOOP. >> IF NOT SO-ON GOTO 1059-LOOP. >> IF NOT SO-FORTH GOTO 1059-LOOP. >> EXECUTE 1050-SUCH-AND-SUCH >> 1059-LOOP. >> >> Keep in mind I haven't programmed in COBOL since Y2K; I had to look up the >> syntax, I probably got part of it wrong nonetheless, and I'll bet there are >> easier ways to do it nowadays. In REXX, for example, they have the ITERATE >> statement: >> >> do jc=1 to 99 >> if x>99 then iterate >> if firstname='ROBERT' then iterate >> if type<>195 then iterate >> if \soon then iterate >> if \soforth then iterate >> call suchandsuch >> end >> >> However you do it, I vastly prefer skip-to-next-item over nested Ifs. But >> I confess that one single nested IF is not going to give me a headache; I >> just react when I see one. Not your fault :). >> >> -----Original Message----- >> From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On >> Behalf Of Gibney, Dave >> Sent: Friday, June 5, 2020 16:17 >> >> Using OP >> IF TVOLL (IND1) NOT = HIGH-VALUE >> AND SMOD (IND1) = 'B' OR 'R' >> >> I would do >> IF TVOLL (IND1) NOT = HIGH-VALUE >> IF SMOD (IND1) = 'B' OR 'R' >> Do the stuff > >---------------------------------------------------------------------- >For IBM-MAIN subscribe / signoff / archive access instructions, >send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
