I had to look up De Morgan's Law. I thought I was pretty good at set theory, but still learned something (a lot) new.
Thanks, Barbara.
Jerry C. Adams
It's better to be lucky than good. Especially if you're not good.
IBM i Programmer/Analyst
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NMM&D
615-832-2730
-----Original Message-----
From: RPG400-L [mailto:rpg400-l-bounces@xxxxxxxxxxxxxxxxxx] On Behalf Of Barbara Morris
Sent: Thursday, February 28, 2019 3:08 PM
To: rpg400-l@xxxxxxxxxxxxxxxxxx
Subject: Re: if statement brain cramp
If all the inner expressions are all negative, then it's often easier to understand with the NOT on the outside.
I find the second one of these two statements easier to understand at a
glance:
- if x <> 1 and not %found
- if not (x = 1 or %found)
If the inner expressions are a mixture of positive and negative, then "it depends" whether it's nicer to put the NOT on the outside.
I can't decide which one is "better" of these two, but I'm leaning towards the first, maybe because of the double NOT in the second one.
- if x <> 1 or %found
- if not (x = 1 and not %found)
Good old "De Morgan's Law".
On 2019-02-27 11:54 AM, Robert Rogerson wrote:
Jeff, I too use that logic often. It drives my boss nuts but to me it
just makes sense...
Rob
On 2/27/2019 9:23 AM, Jeff Crosby wrote:
Don't laugh at me either -
Is this valid
if not ( SML010 <> 5 and M1PLIN = *blanks);
--
Barbara
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