Re: RPGILE V4.3 Gotcha

["Ken Sims at SWS Nevada" <ken.sws@xxxxxxxxx>]

Hi Frank -

>Date: 6 Oct 99 17:31:22 EST
>From: Frank Kolmann <fkolmann@netscape.net>
>Subject: Re: [Re: [Re: RPGILE V4.3 Gotcha]]
>
>"Ken Sims at SWS Nevada" <ken.sws@ke9nr.org> wrote:
>
>Not so Ken, design is OK, its the divide operation that caused the
>intermediate result to have 20 dec places.
>Obviously I needed to do an EVAL(R) but in the end I used the old RPG II
>op codes.

As I mentioned in my response to Jim, since the result of a
divide operation has an indefinite number of digits to the
right of the decimal point, the manual states very clearly
that the total length of the intermediate result will always
be 30.  It also states, though not so clearly, that there
will be as many digits to the left of the decimal point to
prevent overflow (up to the max of 30, of course), with the
rest being to the right of the decimal point to give you the
MAXIMUM POSSIBLE PERCISION WITHOUT OVERFLOW.  The people who
wrote the compiler are not stupid.  The size on the intermediate
result of a divide may look really strange, but it is designed
to give you the MAXIMUM POSSIBLE PERCISION WITHOUT OVERFLOW
(unless it would take more than 30 digits to prevent overflow).

Unless you have small numbers in big fields, a plain ol' EVAL
(i.e. without (R)) works just dandy.  If you do have small
numbers in big fields, then you may need to use (R) or default
it via the H-spec.  But IMNSHO all of this criticism of the
EVAL is unwarranted.

I use lots of EVALs.  I just put into production a whole new
discounting process.  I don't think I have an ADD, SUB, MULT,
or DIV anyplace in the whole thing.  I have yet to have a
problem.  I do use some [perhaps not so] common sense in the
order of the operations within the EVAL, but that's really
no different than needing to the do the same thing if you're
using a series of discrete math operations.

Ken
Southern Wine & Spirits of Nevada, Inc.

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