RE: Moving to RPGIV -- RPG400-L

On Thu, 2004-07-15 at 15:09, Dan Bale wrote:
> Pete, the first thing I did was to use CVTRPGSRC to convert RPG-III apps I
> had written and was fairly familiar with.  The biggest hurdle for me was the
> D-specs, and I've been known to code a snippet of I-specs in RPG-III and
> convert that just to see the equivalent in RPG-IV.  But note that many of
> the newer advanced features of D-specs are not utilized by the converter
> (OVERLAY comes to mind).

If I remember right, CVTRPGSRC doesn't add D-Specs for stand alone
fields, so you'll have to do that by hand.  If you are used to Java and
C++, then the idea of defining all the variables at the top of the
source member won't be a big leap.  I agree it will probably take some
time to get familiar with some of the more advanced D-Spec techniques,
but you'll quickly find them superior to RPGIII.

> There isn't much that doesn't convert and these are typically some arcane
> opcodes that no one uses anyway.

Doesn't everything from RPGIII convert to RPGIV?  I thought it was just
with /free and some expressions and such that things can't convert...

> The conversion also does not change "X   ADD   Y    Z" statements to the
> "Eval   z = x + y".  And there are some rules regarding overflow that cause
> these otherwise identical statements to behave differently that you need to
> learn about.  Today, none of my programs use MOVEx, Z-ADD, ADD, SUB, MULT,
> DIV, Z-SUB opcodes.

There are a couple of utilities out there for converting expressions.  I
think I got one with a book I bought, but it's been 4 years now so I
don't remember what book it was, but you could look for that when making
your purchasing decisions.

> Anyway, after you convert some programs, you'll see that there's really no
> learning curve (especially since you're proficient in Java and C++), and
> you'll see how the syntax between III and IV are different.
> 
> Moving ahead from just converting source, you'll find good information on
> advanced -IV topics on this mailing list, and on several tech newsletters
> (Club Tech comes to mind, there are others).  I keep the online IBM RPG-IV
> Reference handy, as well as the "Who Knew You Could Do That With RPG-IV?"
> redbook.  Bob Cozzi's book is, I think, considered the gold standard for a
> commercial reference, but I have only browsed through others' copies.  You
> should remember to use the archives as well.

Moving to RPGIV is just the beginning of the journey... I don't think it
will take you too long.  For that, there are several books out there
that are specific to helping you make the transition.  The real leap
will come in moving from OPM to ILE.  For that, the "Who Knew..." and
the "ILE Concepts" Manual will prove indispensable.  And by all means do
yourself a favor and get a copy of Cozzi's "Modern RPGIV Language" as a
reference.  These are the books I reference the most.  "RPGIV At Work"
is also pretty decent.  And it goes without saying that this list and
others like it will prove invaluable to you... just check the archives
before you post...

As db said, "Welcome aboard!"

Joel
http://www.rpgnext.com