RE: IF Coding question

["Booth Martin" <booth@xxxxxxxxxxxx>]

Reading aloud is a good trick.  Thanks.

Experience has shown me that there are several places where the technique
used here is useful.  One instance is when defining the opposite grouping is
a tad tricky.  Another is when it seems that later additions to the code
will include more conditions.  The if, else, code, endif  is easily
implemented and easily understood.

Besides, am I the only one that has troubles with OR conditions?    
 
---------------------------------
Booth Martin
http://www.martinvt.com
---------------------------------
-------Original Message-------
 
From: RPG programming on the AS400 / iSeries
Date: 03/30/04 21:30:16
To: RPG programming on the AS400 / iSeries
Subject: RE: IF Coding question
 
Bob,
 
At 3/30/04 09:28 PM, you wrote:
>I don't agree that negative conditional evaluations are "more
>straightforward" than positive logic that is prefixed with NOT.
>It is a known fact that the mind can interpret positive logic much quicker
>than negative.
 
  In both cases we are looking at a negative condition.  My criteria is to
try to read it out loud.  My way reads like you would state it in English:
 
  If  TOT1a does not equal TOT2a or TOT1b does not equal TOT2bc...
 
  Putting the NOT, in this case, before the test is unnecessarily awkward,
IMHO.
 
 
>   But, hey, we're not out to save the world with RPG IV, now are we. :)
 
  One line of code at a time...  :-)
 
  -mark
 
>-----Original Message-----
>From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx]
>On Behalf Of M. Lazarus
>Sent: Tuesday, March 30, 2004 7:41 PM
>To: RPG programming on the AS400 / iSeries
>Subject: RE: IF Coding question
>
>Bob,
>
>   I'm not sure if it's mandated or not (w/o checking the order of
>evaluation in the manual), but the following would be the preferable way to
>mimic the original code:
>
>     If       NOT ( TOT1a = TOT2a and TOT1b = TOT2bc )
>
>   Although, my preference would be:
>
>     If       TOT1a <> TOT2a Or TOT1b <> TOT2bc
>
>   since it's more straightforward.
>
>   -mark
>
>At 3/30/04 06:39 PM, you wrote:
> >It equates to this in RPG IV:
> >
> >    If       NOT TOT1a = TOT2a  and TOT1b = TOT2bc
> >    EXCEPT   HEADR
> >    EXCEPT   TOTAL
> >    ENDIF
> >
> >It is an old "trick" in RPGIII that allows you to do a set of opcodes
when
> >something is NOT true. In other words, it is too hard to code the
opposite
> >condition, so they coded it in "positive logic" and use the ELSE to
reverse
> >the "polarity" of the conditional statement.
> >-Bob Cozzi
> >
> >
> >-----Original Message-----
> >From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@midrange
com]
> >On Behalf Of simafrog
> >Sent: Tuesday, March 30, 2004 8:19 AM
> >To: RPG programming on the AS400 / iSeries
> >Subject: IF Coding question
> >
> >I am trying to understand the point/reason for this code:
> >       TOT1a   IFEQ TOT2a
> >       TOT1b   ANDEQTOT2bC
> >               ELSE
> >               EXCPTHEADR
> >               EXCPTTOTAL
> >               ENDIF
> >Why do you need the "IF" "AND" part? What purpose does this serve?
>
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