In both scenarios the code stinks because you have conditional processing
far away from the
event that cause the condition
A boolean that NotValid or Valid are or if you prefere a namegiven
indicator shold not be testet
100 statements from where it was born.
Regards
Henrik
Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>
Sent by: rpg400-l-bounces@xxxxxxxxxxxx
03-03-2010 19:02
Please respond to
RPG programming on the IBM i / System i <rpg400-l@xxxxxxxxxxxx>
To
RPG programming on the IBM i / System i <rpg400-l@xxxxxxxxxxxx>
cc
Subject
Re: More on RPG style
Hello Joe,
Sorry, I didn't not forget to respond. :-)
On 3/1/2010 7:46 PM, Joe Pluta wrote:
Yet, you still got it wrong. Because clearly the item is valid if it is
found in the ItemMaster. Not that your basic premise is bad; it's just
that there really is no magic bullet.
Yes, you're quite a bit not wrong. :-)
My examples were meant to be:
chain ItemNo ItemMaster;
if not %found;
NotValid = *on;
endif;
. . . 100 lines of code . . .
If (not NotValid);
// use item
endif;
And the simplified example was meant to be:
chain ItemNo ItemMaster;
if not %found;
Valid = *off;
endif;
. . . 100 lines of code . . .
if Valid;
// use item
endif;
Everyone makes mistakes. Please judge the technique based on what I
MEANT to say, rather than on my "doh!" silly mistake.
You need to code what makes sense to you, and then secondarily you
need to consider the person who will maintain the code after you.
I completely, 100% agree with you here. And indeed, that was the exact
point I was trying to make. The goal is to make the code readable, and
in every instance a programmer should be looking to make the code as
readable as possible. To yourself first, and secondarily to the person
who will maintain the code next.
I think the phrase at the opening of my message ("Sorry, I didn't not
forget to respond.") is a perfect example of how extra negatives can
make things harder to understand. If I had simply said "I forgot to
respond" it'd be easy to tell what I was saying. If I had said "I
didn't remember to respond" you'd also have understood -- even though
it's negative logic, it's very simple negative logic. But there's a
point where it goes beyond that. "I didn't not forget" is beyond that
level.
The same is true of computer program logic. The examples in this thread
have been simple ones, and therefore easy to understand even though they
were negative. But it's possible for it to be too convoluted, and
negative logic can be a factor in that.
This was my only point.
FWIW, I disagree with Dennis's statement of "It is considered bad form
to use NOT where avoidable". There are times when it can make a
statement too convoluted, and there are times when it's perfectly
acceptable. The goal should be to make your code as readable as
possible, not to make an arbitrary rule of "never do that."
But it's certainly worth considering when writing the statement. Too
many people aren't taking the time to think to themselves "Is there a
way I can phrase this that will be clearer? Will removing the NOT make
it clearer?" And THAT is really what I'm trying to do -- get people to
think about it.
midrange.com
