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Re: And so? (VMS/XDE)

From cross@spitfire.i.gajendra.net (Dan Cross)
Newsgroups comp.os.vms
Subject Re: And so? (VMS/XDE)
Date 2025-12-02 15:46 +0000
Organization PANIX Public Access Internet and UNIX, NYC
Message-ID <10gn1kh$6o0$2@reader2.panix.com> (permalink)
References <mmenp7F4bqiU1@mid.individual.net> <10gle2k$1q97g$1@dont-email.me> <10gmqrs$ibp$1@reader2.panix.com> <10gn0cq$2d8ve$1@dont-email.me>

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In article <10gn0cq$2d8ve$1@dont-email.me>,
Arne Vajhøj  <arne@vajhoej.dk> wrote:
>On 12/2/2025 8:50 AM, Dan Cross wrote:
>> In article <10gle2k$1q97g$1@dont-email.me>,
>> Arne Vajhøj  <arne@vajhoej.dk> wrote:
>>> On 12/1/2025 8:37 AM, Dan Cross wrote:
>>>> I've long suspected (but I admit I have no evidence to support
>>>> this) that one of the reasons there is so much COBOL code in the
>>>> world is because, when making non-trivial changes, programmers
>>>> first _copy_ large sections of the program and then modify the
>>>> copy, to avoid introducing bugs into existing functionality.
>>>
>>> Copying and modifying code instead of creating reusable libraries
>>> has been used by bad programmers in all languages.
>> 
>> I think it's a little deeper than that.
>
>>> There is also something in the Cobol language.
>>>
>>> Large files with one data division, lots of paragraphs
>>> and lots of perform's is easy to code, but it is also
>>> bad for reusable code.
>>>
>>> It is sort of the same as having large C or Pascal files
>>> with all variables global and all functions/procedures
>>> without arguments.
>>>
>>> It is possible to do it right, but when people have
>>> to chose between the easy way and the right way, then ...
>> 
>> An issue with COBOL is that, given procedures A, B, ..., Z,
>> written sequentially in source, `PERFORM A THRU Z` means that it
>> is difficult to see when procedures B, C, ..., Y are called just
>> through visual inspection since calls to them are implicit; you
>> really need semantically aware tools to do that.  So if you need
>> to change paragraph D, then you run the risk of implicitly
>> changing dependent behavior in your system unintentionally.  You
>> might end up violating some assumption you didn't even know
>> existed; talk about spooky action at a distance.
>
>That is a classical argument found on the internet.

Yes.  I myself have been making it for years.

>But I am not convinced that it is critical.
>
>It is all within one file.
>
>$ search foobar.cob thru,through
>
>should reveal if the feature is used.
>
>Unless the file is very long and the code is very ugly, then
>I believe it should be relative easy possible to track the
>perform flow even in VT mode EDT or EVE.

I'm not at all convinced of that in a large code base; call
graphs resulting in such `PERFORM`s can be too big to trace by
hand.  And many of these extant COBOL applications are quite
large, indeed.

>> Most COBOL programs were written before the era of automated,
>> unit-level testing, so it's extremely unlikely you've got a big
>> suite of tests you can run to attempt to catch such issues.
>> 
>> I imagine that a this results in a lot of (unnecessary)
>> duplication.
>
>That may actually have a huge impact.
>
>No unit tests is a common reason not to change any existing code.

I'm sure that it does.

	- Dan C.

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Thread

And so? (VMS/XDE) gcalliet <gerard.calliet@pia-sofer.fr> - 2025-10-29 15:48 +0100
  Re: And so? (VMS/XDE) Chris Townley <news@cct-net.co.uk> - 2025-10-29 15:19 +0000
    Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-10-29 19:03 -0400
      Re: And so? (VMS/XDE) Chris Townley <news@cct-net.co.uk> - 2025-10-29 23:16 +0000
        Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-10-29 19:25 -0400
          Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-10-30 11:30 +0000
  Re: And so? (VMS/XDE) drb@ihatespam.msu.edu (Dennis Boone) - 2025-10-29 16:13 +0000
    Re: And so? (VMS/XDE) Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2025-10-29 18:48 +0000
      Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-10-29 15:52 -0400
        Re: And so? (VMS/XDE) Chris Townley <news@cct-net.co.uk> - 2025-10-29 21:45 +0000
      Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-10-29 15:59 -0400
      Re: And so? (VMS/XDE) gcalliet <gerard.calliet@pia-sofer.fr> - 2025-10-30 09:19 +0100
        Re: And so? (VMS/XDE) Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2025-10-30 13:12 +0000
          Re: And so? (VMS/XDE) gcalliet <gerard.calliet@pia-sofer.fr> - 2025-10-30 20:05 +0100
          Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-10-30 15:59 -0400
            Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-10-30 22:28 +0000
            Re: And so? (VMS/XDE) Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2025-11-03 13:31 +0000
              Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-03 15:18 -0500
              Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-03 15:28 -0500
                Re: And so? (VMS/XDE) Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2025-11-04 13:59 +0000
                Re: And so? (VMS/XDE) Subcommandante XDelta <vlf@star.enet.dec.com> - 2025-11-05 07:57 +1100
                Re: And so? (VMS/XDE) Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2025-11-05 13:25 +0000
                Re: And so? (VMS/XDE) bill <bill.gunshannon@gmail.com> - 2025-11-06 08:44 -0500
                Re: And so? (VMS/XDE) gcalliet <gerard.calliet@pia-sofer.fr> - 2025-11-20 13:05 +0100
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-04 19:34 -0500
              Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-11-07 14:01 +0000
                Re: And so? (VMS/XDE) Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2025-11-10 14:12 +0000
                Re: And so? (VMS/XDE) bill <bill.gunshannon@gmail.com> - 2025-11-10 10:19 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-10 15:43 -0500
                Re: And so? (VMS/XDE) antispam@fricas.org (Waldek Hebisch) - 2025-11-11 15:23 +0000
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-11 20:59 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-11 19:57 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-11 20:02 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-12 03:51 +0000
                Re: And so? (VMS/XDE) Chris Townley <news@cct-net.co.uk> - 2025-11-12 01:50 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-11 21:00 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-12 03:48 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-12 15:12 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-12 21:01 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-12 16:06 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-14 23:35 +0000
                Re: And so? (VMS/XDE) antispam@fricas.org (Waldek Hebisch) - 2025-11-15 00:24 +0000
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-15 02:41 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-14 22:18 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-15 06:00 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-15 09:22 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-15 22:16 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-15 18:12 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-18 07:25 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-18 09:19 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-20 23:07 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-20 19:41 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-20 19:55 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-21 19:09 -0500
                Re: And so? (VMS/XDE) Andreas Eder <a_eder_muc@web.de> - 2025-11-15 12:15 +0100
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-15 08:27 -0500
                Re: And so? (VMS/XDE) Dave Froble <davef@tsoft-inc.com> - 2025-11-29 19:49 -0500
                Re: And so? (VMS/XDE) antispam@fricas.org (Waldek Hebisch) - 2025-11-30 05:44 +0000
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-30 06:33 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-30 14:21 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-30 14:23 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-30 16:04 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-30 16:09 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-30 16:11 -0500
                Re: And so? (VMS/XDE) Chris Townley <news@cct-net.co.uk> - 2025-11-30 21:49 +0000
                Re: And so? (VMS/XDE) antispam@fricas.org (Waldek Hebisch) - 2025-11-30 22:18 +0000
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-12-14 01:37 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-30 17:44 -0500
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-12-01 13:37 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-01 16:02 -0500
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-12-01 21:26 +0000
                Re: And so? (VMS/XDE) bill <bill.gunshannon@gmail.com> - 2025-12-01 17:46 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-01 18:50 -0500
                Re: And so? (VMS/XDE) bill <bill.gunshannon@gmail.com> - 2025-12-01 20:23 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-01 20:44 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-01 20:55 -0500
                Re: And so? (VMS/XDE) bill <bill.gunshannon@gmail.com> - 2025-12-01 22:05 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-01 22:18 -0500
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-12-02 12:59 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-01 20:06 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-01 20:14 -0500
                Re: And so? (VMS/XDE) bill <bill.gunshannon@gmail.com> - 2025-12-01 20:15 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-01 20:31 -0500
                Re: And so? (VMS/XDE) bill <bill.gunshannon@gmail.com> - 2025-12-01 21:39 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-01 22:03 -0500
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-12-02 13:50 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-02 10:25 -0500
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-12-02 15:46 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-02 10:57 -0500
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-12-02 19:03 +0000
                Re: And so? (VMS/XDE) Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2025-12-01 13:49 +0000
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-12-01 18:59 +0000
                Re: And so? (VMS/XDE) Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2025-12-01 19:58 +0000
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-12-02 15:42 +0000
                Re: And so? (VMS/XDE) Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2025-12-03 14:07 +0000
                Re: And so? (VMS/XDE) Dave Froble <davef@tsoft-inc.com> - 2025-12-09 00:19 -0500
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-12-10 18:38 +0000
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-12-01 21:23 +0000
                Re: And so? (VMS/XDE) bill <bill.gunshannon@gmail.com> - 2025-12-01 17:50 -0500
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-12-02 13:56 +0000
                Re: And so? (VMS/XDE) Dave Froble <davef@tsoft-inc.com> - 2025-12-08 23:57 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-10 15:35 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-10 15:37 -0500
                Re: And so? (VMS/XDE) antispam@fricas.org (Waldek Hebisch) - 2025-11-11 14:47 +0000
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-11 20:54 +0000
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-11-12 17:04 +0000
                Re: And so? (VMS/XDE) Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2025-11-13 13:42 +0000
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-11-16 02:00 +0000
              Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-11 10:50 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-11 20:57 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-11 18:56 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-12 03:56 +0000
                Re: And so? (VMS/XDE) cross@spitfire.i.gajendra.net (Dan Cross) - 2025-11-12 13:43 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-12 14:54 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-12 21:02 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-12 16:10 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-14 05:47 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-14 16:49 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-18 07:29 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-18 13:52 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-20 23:09 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-20 19:31 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-21 01:32 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-20 19:36 -0500
                Re: And so? (VMS/XDE) David Wade <g4ugm@dave.invalid> - 2025-11-12 21:43 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-12 16:57 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-13 02:45 +0000
                Re: And so? (VMS/XDE) David Wade <g4ugm@dave.invalid> - 2025-11-13 10:36 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-13 16:13 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-14 23:39 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-14 16:58 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-17 21:19 -0500
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-12-18 06:47 +0000
                Re: And so? (VMS/XDE) "Niels S. Eliasen" <nse@eliasen.co> - 2025-12-19 11:16 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-19 08:07 -0500
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-12-19 08:53 -0500
        Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-10-30 15:52 -0400
          Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-10-30 22:26 +0000
            Re: And so? (VMS/XDE) jgd@cix.co.uk (John Dallman) - 2025-11-01 16:40 +0000
              Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-01 13:04 -0400
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-01 20:18 +0000
                Re: And so? (VMS/XDE) jgd@cix.co.uk (John Dallman) - 2025-11-04 22:17 +0000
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-04 22:25 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-04 19:13 -0500
              Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-01 20:14 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-01 20:02 -0400
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-02 01:34 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-01 21:44 -0400
            Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-01 17:44 -0400
              Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-01 22:13 +0000
                Re: And so? (VMS/XDE) Arne Vajhøj <arne@vajhoej.dk> - 2025-11-01 20:14 -0400
                Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-11-02 01:30 +0000
        Re: And so? (VMS/XDE) Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-10-30 22:29 +0000

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