Re: Chain vs SetLL/ReadE

On Tue, 2008-09-02 at 11:13 -0500, Lim Hock-Chai wrote:

Barbara,
For the sake of getting us out of all these misery, can't you just
create some new bifs like %chain, %read, %reade... that return %status
as return code? :).

If language design is up for discussion, let me suggest ...

forRecordSet ( keyfields ) filename;
// do something
endFor;

or

forRecordSet ( keyfields ) filename;
// do something per record
ifEmptySet;
// do something else just once
endFor;

In each case `( keyfields )` is optional; in its absence, the code
starts at the current file position and loops until eof (or explicit
exit, of course).

Cheers,
Terry.

<vhamberg@xxxxxxxxxxx> wrote in message
news:<mailman.7854.1220371362.2545.rpg400-l@xxxxxxxxxxxx>...

Terry

Thanks - that is the other form of the READx loop - I guess I don't

care for it, as you have 2 comparisons for every time through instead of
1 - I think!! Might get optimized away in any case, but we don't know
that.

Seems to be we pays our money and takes our choice!

Vern

-------------- Original message --------------
From: Terrence Enger <tenger@xxxxxxxxxxxxxxxx>

On Tue, 2008-09-02 at 08:34 -0500, Chandra Krieg wrote:

Hello all,

I have been told that the preferred method of random record

retrieval is to

use the SetLL, then do a ReadE and check for the %EOF indicator.

Why is this preferred over using a Chain with %found or even

checking for

%Equal on the SetLL before reading the file? I have been told that

the Chain

doesn't do what I'm expecting it to but I've never had issues in the

past.

I have read the archive posts and found opinions on the subject

but no

concrete explenation as to why. As with some of the posts I don't

understand

why you would want to readE the file if the SetLL didn't find an

%equal match or

why if you plan to read the file a chain isn't appropriate.

I'm being told to use the following code instead of a Chain.

SetLL (KeyFields) FIleName;
ReadE (KeyFields FIleName;
DoW Not %EOF(FIleName);
do my stuff
ReadE (KeyFields) FileName;
EndDo;

Well, I can imagine that it might be deemed a bit simpler to avoid
having both a CHAIN and a READE for one file in one chunk of code.

But

my own taste would be to have only one READE, even at the cost of

two

more lines of code.

SetLL (KeyFields) FileName;
DoW 0=0;
ReadE (KeyFields) FileName;
if %eof( FileName );
leave;
endIf;
do my stuff
EndDo;

Hope I do not sound too much like a broken record.

Cheers,
Terry.

Any explanations would be helpful!

TIA!

Chandra Krieg
i5 Programmer/Analyst
RateWatch
(P) 1.800.348.1831 ext 311
(F) 1.920.568.1403
www.rate-watch.com

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