• Subject: Re: COBOL and RPG was Welcome new members
  • From: Howard Weatherly <hweatherly@xxxxxxxxxxxx>
  • Date: Thu, 02 Dec 1999 16:07:27 -0500

Ok, you can have the last word except for....<big grin> the prototyping you 
mention
only is a restriction because IBM says it is not permitted. The proof can be 
defined
in operating systems that are extensible such as MPE or MCP, each allow binding 
code
to the operating system which translates to additional function in each native
language. Case in point, Address everyone spells it differently. At one place I
worked we bound a DC Algol (Yes I am that old!) subroutine to correct spelling 
into
MCP, part of the function was to verify the input and output parms (I thought 
this
part to be useless since each was 100 in 46 formated out). Any COBOL program 
(then
68) had access to this using  native COBOL structures eg... Compute
FNAME(INPFIELD,OUTFIELD) FNAME being the bound code. Ok so its not a call, it
looketh like a function nevertheless we are only limited by what the vendor 
allows,
not by the language itself. So today we get APIs.

Oh and yes, the declaratives work just fine, like anything it takes time to 
learn.

As far as the corr dups, I could have misread what you said but it appeared to 
be
that you could not have duplicated names. Since you explained that you do not 
want
more than one name for any data element, Im sure I misread it.

Jon.Paris@halinfo.it wrote:

> I am "bilingual" and was involved in the compiler design for the current RPG 
>and
> COBOL compilers for the 400.  SO I like each for its strengths and work with 
>the
> compiler folks to suggest places where features of one can be used in the 
>other.
> The LIKE keyword in COBOL and the new date support in the language being
> examples of the kind of thing I mean.
>
> Other replies below and that's it - as much fun as it is, this wastes too much
> time.
>
> Howard Weatherly <hweatherly@dlis.dla.mil> on 12/02/99 10:14:44 AM
>
> Please respond to COBOL400-L@midrange.com
>
>
>
>
>
>
>
>  To:      COBOL400-L@midrange.com
>
>  cc:      (bcc: Jon Paris/HAL/IT)
>
>
>
>  Subject: COBOL and RPG was Welcome new members
>
>
> Jon, +-999,999,999,999,999,999 is a rather large number, unless we are talking
> about
> how much money the government wastes....:-)
>
> File erors are trapped by using Declaratives and yes the declarations can trap
> or do
> anything!
>
> <<< You mean you know someone who can actually make that feature do something
> useful! I always code for file status - its far simpler.<<<
>
> You certainly can have duplicate names in multiple structures as long as you
> qualify
> the name using the structure, the structure can ascend to the file name for 
>file
> data and to the 1 level for storage data. You can not have duplicate level 77
> items,
> no way to qualify, you can have duplicate 1 levels as long as you provide
> redefinition (although this is not very useful, there are times when 1 levels
> are
> coppied as file records which are qualified to the file).
> The corresponding is very useful for element extraction when you want to
> rearrange
> data without writing a novel, and example is dates (move corr date1 to date2
> where
> date1 is mmddyyyy and date2 is yyyymmdd) or if I dont want replication, (move
> corr
> field1 to field2 where field1 has 10 fields A thru J and field 2 has every 
>other
> of
> A C E...).
>
> <<< I'm very familiar with these features and can't think what I said to 
>prompt
> this comment. Qualification of reference can be very useful, but the notion 
>that
> one name = one piece of data is fundamental to the RPG language and cannot
> easily be changed.  When designing RPG IV we looked at a number of ways of
> bringing this into the langauge while maintaining compatibility but couldn't
> come up with a good one. Effectively Move Corresponding is a code generating
> statement and similar syntax should be possible in RPG - maybe one day.
> Interstingly enough, I was responsible for the addition of the ability to have
> the COBOL 400 compiler list the fields that "corresponded". Why did we add it?
> becuase 90% of all the COBOL programmers we talked to did not use Move
> corresponding because they couldn't work out what did and did not 
>correspond!<<<
>
> While I am not sure what you mean by prototyping, I suspect you mean define it
> once
> use it everywhere? Yes we can! (copy something replacing X by Y) and for
> subprocedures? I do not know what you mean here, but whatever it is, it can be
> done!
>
> <<< Prototyping is the ability to define what the parameters and return value 
>on
> a call should look like. That way the compiler can validate that the call is
> correct (and in some circumstances can generate temporary fields and move the
> data to ensure a match. COBOL _cannot_ do this in any dialect I have ever 
>seen.
> Subprocedures provide an ability to extend the scope of the langauge (much 
>like
> C functions). If I have a subprocedure that calculates the day of the week 
>given
> a date then in RPG I can code: Eval DayNumber = DayOfWeek(TheDate).  In COBOL
> this can only be done through CALL 'DayOfWeek" Using TheDate Returning
> DayNumber. Not quite so elegant is it - and the RPG will validate the 
>parameters
> the COBOL cannot.<<<
>
> Now let me say this about both COBOL and RPG, I like RPG when it is used for
> reports, that is where it makes the most sense to me, I like the Cycle doing 
>the
> work and the ease with which reports can be modified. The fact that you may 
>need
> some calcs does not bother me either, I can also tolerate a forced read now 
>and
> agian and some file extensions for table processing, but once the line is
> crossed
> (and this line is different for everyone) I find that RPG wil lose its ability
> to be
> coherent (to me) whereas a well written COBOL program (the key word is "well
> written") has the ability to allow me to understand the process(s) without 
>being
> familliar with the system. I can not do that with an RPG program, of course if
> maybe
> I used RPG as much as I use COBOL, my tolerance line would shift probably.
>
> <<< I can't help feel that you're comparing RPG II with COBOL.  I _never_ use
> the RPG cycle and it is not taught in most of the schools these days. An RPG
> program written with the same degree of skill as a COBOL one should be every 
>bit
> as easy to understand<<<
>
> Jon.Paris@halinfo.it wrote:
>
> > For the most part I agree that there are still a number of features that are
> > present in COBOL that RPG lacks.  As to your individual comments:
> >
> > - Indented code
> >
> > This is supported to a limited degree in D specs and C specs.  There will
> likely
> > be full support in C specs in the next RPG release.
> >
> > - long field names (and be able to use them in calcs)
> >
> > You mean 2056 characters isn't enough <grin>.  In practice I find the 
>current
> > (practical) limit of 14 to be more than adequate.  If I recall correctly the
> > COBOL maximum is 30 but I never used them all. By contrast RPG supports 30
> digit
> > numerics while COBOL's default behavior is still 18. Now that _is_ a
> limitation
> > that I have hit.
> >
> > - record handling
> >
> > Not clear what you mean by this. By using RPGIV's externally described DS
> > support together with the Prefix keyword I can handle things at the record
> > level.
> >
> > - error trapping in free-format calcs (like EVAL x=y * z ON ERROR do 
>something
> > else)
> >
> > This has been "announced" by IBM in the form of the MONITOR group, which in
> many
> > ways is superior to COBOL's On error (which doesn't handle all errors by the
> > way). They are considering the possibility of allowing this to be more
> granular
> > (a la COBOL) but MONITOR is probably better since in general I don't care 
>if a
> > single statement "blows" I want to know if anything goes wrong in a 
>logically
> > related group of statements.
> >
> > - data replication: move CORR to replicate data to fields of same name in
> other
> > records
> >
> > There has never been a need for this in absolute terms since you cannot have
> two
> > fields of the same name in different structures. I would love to see them 
>do a
> > similar thing though where the field prefix governed which fields were 
>alike.
> >
> > - (and the converse: unlike RPG, dont replicate the data if the programmer
> > doesnt want to!)
> >
> > You can already handle this with Prefix at the file level.
> >
> > The one biggie that COBOL is missing for me is prototyping of program calls
> and
> > the ability to define subprocedures. These have made a huge difference in my
> RPG
> > coding but I can't do it in COBOL.
> >
> > +---
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