RE: RPG Indicators -- RPG400-L

Yeah, you took the bait, didn't ya?  (heh, heh!)

I thought for a minute or so before deciding to respond (and I'll probably
regret it later <g>), but...  (donning asbestos suit):

> The main reason is that there is one less logical test inside the loop.  
      c                   DoU       %EoF( FileName )
      c     Key           ReadE     FileName
      c                   If        not %EoF( FileName ) 
And the problem is???  I think it's pretty hard to miss the intent here.
And, unless someone tells me that the If statement after the ReadE is a CPU
hog, I can't see any costs.  Also, the loop-ending EndDo always has the
EndIf right before it, and I document the two lines in the comment area with
"DoU %EoF( FileName )" and "If not %EoF( FileName )".  

> I can't think of any case where I've wanted to enter a loop via DOU in the
case where there aren't any records.
In that case, you would probably _never_ use DOU, right?  Because it isn't
just that you have no _records_ to process, it's the fact that you have no
work to do in the loop.  Therefore, it would seem to follow that you would
always do a "priming" test before you enter the loop.

Sigh.  I'm beginning to regret this already.  WAIT!  DON'T PRESS THAT SEND K

> -----Original Message-----
> From: Rich Duzenbury [SMTP:rduz@westernmidrange.com]
> Sent: Sunday, April 16, 2000 12:06 AM
> To:   RPG400-L@midrange.com
> Subject:      RE: RPG Indicators
> 
> OH BOY.
> 
> I don't know why I'm responding to this one.  I think it's a religion
> thing...but here's my .02 anyway.
> 
> I am a 'true believer' of doing the priming read, using the do-while loop,
> and then reading just before the enddo.
> 
> Why do I think it's better?  The main reason is that there is one less
> logical test inside the loop.  EOF is checked once and only once in each
> iteration.  Also, the loop is never entered if there are no records.  I
> can't think of any case where I've wanted to enter a loop via DOU in the
> case where there aren't any records.
> 
> In my opinion, it's RPG that is forcing this issue on us.  If RPG were to
> have the ability to do the read and test on the same line, we'd all use
> DOW, I think with little question.  In C-ish languages, we would write it
> thusly:
> 
> while (readfile('OURFILE')==TRUE)
>   {
>   ... do our processing...
>   }
> 
> or perhaps
> while (readfile('OURFILE'))
>   {
>   ... do our processing...
>   }
> 
> Of course, the downside is that if you need to modify the read statement,
> you have to do it twice.  The other rule of thumb I try to stick to is to
> have read loops no longer than can comfortably be seen on one SEU screen.
> If I have more processing than can be done 'between the reads', I
> typically move it into a subroutine.
> 
> <donning my flameproof gear>
> 
> Regards,
> Rich
> 
> 
> -----Original Message-----
> From: owner-rpg400-l@midrange.com [mailto:owner-rpg400-l@midrange.com]On
> Behalf Of Peter Dow
> Sent: Saturday, April 15, 2000 9:43 PM
> To: RPG400-L@midrange.com
> Subject: Re: RPG Indicators
> 
> 
> I agree Dan. This has the added advantage that using ITER makes sense,
> although it also has the disadvantage that you have to repeat the
> condition.
> If there are more conditions than just eof, it could be modified something
> like this:
> 
>       c     Key           Setll     FileName
>       c                   DoU       %EoF( FileName )
>       c     Key           ReadE     FileName
>       c                   If        %EoF( FileName ) or
>       c                             (a = b and c = d) or
>       c                             e = f
>       c                   leave
>       c                   EndIf
>        ***   do stuff
>       c                   EndDo
> 
> 
> Peter Dow
> Dow Software Services, Inc.
> 909 425-0194 voice
> 909 425-0196 fax
> 
> ----- Original Message -----
> From: Bale, Dan <DBale@lear.com>
> To: <RPG400-L@midrange.com>
> Sent: Friday, April 14, 2000 12:07 PM
> Subject: RE: RPG Indicators
> 
> 
> > My preference is to just have one file input operation for the loop,
> i.e.:
> >
> >      c     Key           Setll     FileName
> >      c                   DoU       %EoF( FileName )
> >      c     Key           ReadE     FileName
> >      c                   If        not %EoF( FileName )
> >       ***   do stuff
> >      c                   EndIf
> >      c                   EndDo
> >
> > This has always worked for me.
> >
> > - Dan Bale
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