RE: Does the recommendation against variable names starting with SQL apply to constants?

I think, and I may be wrong here, but the reason that David added the long named constant instead of replacing it, was that the constant was defined in a copy book and used in multiple modules. Which may make it a non-trivial task to replace the cXO constant name with the long name.

Duane Christen


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-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Charles Wilt
Sent: Friday, September 03, 2010 11:54 AM
To: RPG programming on the IBM i / System i
Subject: Re: Does the recommendation against variable names starting with SQL apply to constants?

Scott / Eric,

I think you missed the part where David said that the constant cX0 = 'X0' was already defined in the code by somebody else.

Which to him, me and you two of course makes little sense.

David added a constant with a long (and presumably meaningful) name.
Which is good.

The remaining issue IMO, is that he just added the meaningfully named constant instead of replacing the meaningless cX0 constant.

Charles


On Fri, Sep 3, 2010 at 11:32 AM, Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx> wrote:

On 9/3/2010 3:59 AM, David FOXWELL wrote:

Working on a RPGIII that has just been converted to IV.
Need to test a field to see if its value is 'X0'.

So why not do this?

    IF Field = 'X0';
      //whatever
    endif;

Or in the older RPGIII-like syntax:

    C     FIELD1        IFEQ      'X0'

I guess I don't understand why you'd use a constant like cX0.  It
provides no clarity to the code -- in fact, it just makes the code
harder to read, because now you have to see what value cX0 contains...
whereas if you compare to the literal 'X0', it's obvious.

You should only use constants where the name of the constant CLARIFIES
it's meaning.

For example, you could change this:

   If Field1 < 5;

To this:

   If Field1 < MINIMUM_PRICE;


(or in RPGIII like syntax):

   C     FIELD1        IFLT      MINPRC

You now know what the 5 meant...  whereas before, you either had to
guess, or look for comments/documentation that explained it.  Naming
the constant something like c5 wouldn't have clarified anything, and
therefore would've been a waste of your time & the "next guy's" time.

The name of a variable/constant should never be a simple echo of it's
value.  That's pointless.
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