Re: Looking into the Program stack

[Buck Calabro <buck.calabro@xxxxxxxxxxxxxxxxx>]

Istvan Rudas wrote:

>>>>Kent wrote:
>>>>We have a program running for a couple of hours (7). 
>>>>When looking into the
>>>> ... ... 
>>Well, OK, I'll try to answer it anyways.  (I'll assume that
>>this is one of only a few programs you haven't yet converted
>>to RPG IV, right? :-)
>
>This (last above) sentence in your very interesting answer to Kents
>question gives me the idea, that you may suggest for OPM-
>Programmers to convert them quickly and without major 
>changes - as the IBM CVT Command does it.
>
>(a) In a specific project, my collegue and I have only 20 Fingers for
>maintaining a 700 PGM (OPM) Package...

-snip-

Guten tag!   Wie gehts?  (Hi!  How's it going?)
Converting from RPG III to RPG IV is not the same as converting from RPG III
to Cobol, or C or Java.  RPG IV is not another language, merely a newer
version of good old RPG III.  The only difference you will find after
running CVTRPGSRC are the new D specifications.  These take he place of the
E specifications and the Data Structure specifications.  Every other line of
code is exactly the same as in RPG III.

I have found that maintaining existing, working applications is very much
easier after conversion to RPG IV for the following reasons:
1) Fewer restrictions on variable sizes - 32k character fields, etc.
2) Longer, meaningful field names in mixed case.  Which is easier to
understand: NAME or CustomerName, VendorName?

I convert each program only when I need to make changes.  In the beginning,
do not worry at all about service programs or subprocedures.  Use the same
logic you always used to decide what should go into a subroutine and what
should go into a separate program.

When you are comfortable with the D specifications (in a day or so) <grin>
think about using a subprocedure in place of a new subroutine.  Don't tear
up existing, working code - just make the new code so it can take advantage
of RPG IV's strengths.  Compile the programs containing subprocedures in the
QILE activation group so you don't have to worry about what to name your
activation groups.  Once you use subprocedures and their local variables you
will be so happy to have this support and you will wonder why it took so
long to start using RPG IV.

Even if you never use a BIF like %size, or never use an EVAL, I would very
strongly urge you to convert to RPG IV just for the subprocedure support.
If you use /COPY now to bring in subroutines you can use the exact same
philosophy with subprocedures.  
I hope this helped!

Tschuess!
Buck Calabro
Aptis; Albany, NY

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