RE: Resetting %EOF

[Jim Langston <jlangston@xxxxxxxxxxx>]

Dan,

I have coded like this in the past, the only thing I didn't like about it
was the if statement that could get extremely large if the record processing
was complex.  The other option is to use the leave statement, but I
personally don't like to use leave or other type of break out of the loop
instructions.

Then again, I've been bitten by the 2 reads before, when I needed to change
the read statement for some reason and only remembered to change one of the
2 and forgot about the other one.  One way I handled this in the past with a
complex read statement (setting up variables, etc..) was to actually put the
read and supporting statement in a subroutine, and call the subroutine each
time so I only had to change the read once, not elegant either.

I don't think there is a truly elegant way to do this in RPG, although C has
solved the problem with it's syntax:

while ( read(somefile, somebuffer) != NULL )
{

}

which we don't seem to have (yet) in RPG.

I flip flop on how I handle this now and then, and am not really happy with
any method in RPG right now.

Regards,

Jim Langston

-----Original Message-----
From: Dan Bale [mailto:dbale@samsa.com]

<sigh> <asbestos suit on> I think I'm gonna regret this, however, Juan, you
should know that your original code was close.  I tend to respectfully
disagree with the "two reads in a loop" camp, as Jim provided in his code.
I am definitely in the "one read in a loop" camp.  The only changes I would
have made to your original code:

 C     KlistB        SetLL     IN057P2
 C                   DOW       Not %EOF(IN057P2)
 C     KlistB        ReadE     IN057P2
 C                   If        %EOF(IN057P2)
 C                   Leave
 C                   EndIf
 C  ... do your stuff
 C                   EndDo

would have been to use a DoU %EOF(IN057P2) in place of the DOW, and use If
Not %EOF(IN057P2) in place of the If %EOF(IN057P2) & Leave.  Here's how I
would normally code what I believe you are trying to accomplish:

 C     KlistB        SetLL     IN057P2
 C                   DOU       %EOF(IN057P2)
 C     KlistB        ReadE     IN057P2
 C                   If        Not %EOF(IN057P2)
 C  ... do your stuff
 C                   EndIf                  >If Not %EOF(IN057P2)
 C                   EndDo                  >DOU %EOF(IN057P2)

In this case, you do not need to prime your %EOF because you are not testing
it until the EndDo, after you've attempted a ReadE (note the DOUntil vs.
DOWhile).  I *personally* find this much easier to read & maintain than the
READ before the loop and at the bottom of the loop technique.  Additionally,
if you wanted to perform data selection on your read input, you've already
got your If statement, i.e.:

 C                   If        Not %EOF(IN057P2)
 C                              and INRcvDate = TodaysDate

HTH

<keeping the asbestos suit on>