Re: Passing Parms

Yes, I agree.  One of the issues I had been having trouble with was
conflicting parms from application to application.  Sometimes dates were
alpha, sometimes numeric.  Sometimes the customer number was 7/0, other
times 15/5.   The parms were usually consistent, but not always.  Another
issue was the looking up of the same information over and over in a single
application.

In any event, times have changed and Scott's points are right on.  It is
time to change, too.
 
---------------------------------
Booth Martin
http://www.martinvt.com
---------------------------------
-------Original Message-------
 
From: RPG programming on the AS400 / iSeries
Date: 10/27/05 15:53:15
To: RPG programming on the AS400 / iSeries
Subject: Re: Passing Parms
 
 
Question - whether you change the number of parameters or the component of
a single parameter, surely ALL programs that call the single/multiple
parameter program MAY need to be retrofitted for the change - depending
upon what that change is? In other words, some analysis will need to be
done either way.
 
 
 
Alan Shore
 
NBTY, Inc
(631) 244-2000 ext. 5019
AShore@xxxxxxxx
 
 
 
             Scott Klement
             <rpg400-l@scottkl
             ement.com>                                                 To
             Sent by:                  RPG programming on the AS400 /
             rpg400-l-bounces@         iSeries <rpg400-l@xxxxxxxxxxxx>
             midrange.com                                               cc
 
                                                                   Subject
             10/27/2005 04:16          Re: Passing Parms
             PM
 
 
             Please respond to
              RPG programming
              on the AS400 /
                  iSeries
             <rpg400-l@midrang
                  e.com>
 
 
 
 
 
 
 
> Isn't this a lot easier than tracking down all the programs that would
need
> lines of code changed, too?
 
Why not make the recompiles unnecesary?  Wouldn't that be less/easier
maintenance?  I suppose you enjoy mass-recompiles?
 
Suppose you have 50 computers to deploy the changed program on.  Now you
have to find out, on each computer, which programs call the one you've
changed, and you have to recompile/replace them all.  And this all has to
be done while nobody is using any of them. Isn't that a lot of work?
 
What if those computers aren't all under your control. What if you sell
software to (for example) cleanse an address.  The client has written
software that calls your program from their own code.  Now you change/add
a parameter to your program, and you have to ship out a new copy to every
customer, along with a new copy of the file that the ext data structure is
based on, and get every customer to recompile all of their programs that
call yours.
 
Because of this, people will resist installing the update. They'll put it
off.  In the mean time, you have to support bugs in the new version AND
the old one because the customers need time to make the changeover.
 
You could've eliminated all of this simply by making it so that the
calling programs DON'T NEED TO BE RECOMPILED. And that's much easier to do
with single parameters than it is with data structures.
 
Furthermore, since single parameters are all independent of one another,
you can lessen the impact of changes so that it affects fewer people if
you use single parameters.
 
I realize that not all of the things I've listed here apply to everyone
who writes programs -- but you haven't listed a single reason why data
structures work better.  Indeed, your only argument so far was for using
externally defined fields for parameters!  That can be done with single
parameters as well as data structures.
 
You still haven't told me why data structures are easier to maintain!  How
do they make maintenance easier?
 
The advantage to data structures is that you can group fields together
when they belong to a "set" of fields.  For that, data structures are
brilliant.  It's exactly what they're intended for.
 
But simply passing all parameters as data structures as a rule of thumb
doesn't make any sense to me.
 
 
> I ought to say this:  as with so many things, there is no single right
> solution.  creating a data structure for one parm in a standalone
> application would seem silly.  Using the data structure is just one more
> bullet in the programmer's gun belt, imho.
 
The question is:  if he uses that bullet, will he shoot himself in the
foot?
--
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