Re: Moving to RPG 4

[Buck Calabro <buck.calabro@xxxxxxxxxxxxxxxxx>]

Kathy Wyatt wrote:
 
> I have a fairly dumb question in regard to the difference between RPGIV
and
> ILE. When I write an RPGIV I always use type of RPGLE to have the extended
C
> spec, etc. Do I not have to use the LE?  If not, how else do I access the
D
> and extended C specs?  I'm afraid I literally haven't had time to read the
> RedBooks. No internet at work, heck no PC for that matter, just a dumb
> terminal!

SEU recognises which syntax checker to use by the member type.  Also, PDM
knows which compiler to use by the member type.  The file name (QRPGLESRC)
can actually hold any type of source.  I've been in shops that have one
source file called SOURCE - it holds CLP's, PF's, RPG's, etc.  

As far as the differences betwixt RPG IV and ILE RPG, the differences are
mostly marketing!  Well, not quite true, but close enough.  RPG IV is a
language, which uses D specs, new operation codes and so on (compared to
RPG/400)  ILE is a run time environment which allows the programmer to use
features like service programs and activation groups.  Where the two overlap
is when you want to create modules (CRTRPGMOD) and bind them (by copy) into
a program (CRTPGM).  

If you want to learn RPG IV, don't worry at all about binding or activation
groups.  I created my beginning RPG IV programs with PDM and I use these H
specs: H dftactgrp(*no) actgrp('QILE')  and I add dbgview(*list) to the
command line when I take PDM option 14.

To start, take your favourite RPG/400 program and convert it to RPG IV:
crtsrcpf qrpglesrc rcdlen(112)
cvtrpgsrc qrpgsrc mypgm logfile(*none)

Start PDM and take a look.  It converts arrays (E specs) to D specs and not
much else.  You haven't got a PC at work so you need to get a hard copy of
the RPG manuals.  I believe they are shipped with the compiler, so you
should have an RPG Reference and an RPG Programmer's guide.  Most of the
cool stuff is associated with the new free format opcodes: IF, SELECT/WHEN,
EVAL.  Once you're comfortable with that, take the next step and write a
subprocedure.  Even if you never use ANY of those new opcodes or never write
a procedure, you'll absolutely LOVE reasonable sized, mixed case field names
(no more CSLCCD; instead you can use custLocCode.)

When you're ready for that, there are several of us who would be very happy
indeed to send you some example code for you to start with.  In the interim,
read all you can: buy a book from http://www.midrange.com (it helps support
this list) or download one from IBM: http://www.as400.ibm.com  (use the
Library link).

Buck Calabro
Aptis; Albany, NY
"We are what we repeatedly do.
 Excellence, then, is not an act, but a habit." --Aristotle


Billing Concepts Corp., a NASDAQ Listed Company, Symbol: BILL
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