RE: IFS files and VARPG

I am curious Larry.  I believe I understand your comments, but I do not
understand where you are going with the discussion.

What is the benefit  to the orgnization of progrms that use open(), etc?  
What is better about that process than F-specs?


 
---------------------------------
Booth Martin
http://www.martinvt.com
---------------------------------
-------Original Message-------
 
From: RPG programming on the AS400 / iSeries
Date: 01/21/06 14:37:09
To: rpg400-l@xxxxxxxxxxxx
Subject: RE: IFS files and VARPG
 
Hi Jon,
 
(doffing cap, and looking sheepish...)
 
<snip>
You are making the classic mistake of ignoring history - and in this case
that gives you a completely false sense of the situation. When VARPG was
being designed, conventional RPG could not handle IFS files - at all.
 
So, when deciding how to support local PC files the VARPG designers did
exactly what you are suggesting, they asked themselves "How does RPG do
it?".  The answer of course was F-specs.  Voila!  Simple - make VARPG handle
PC files the same way - through F-specs.  So that's what was done.
</snip>
 
I can see how the compilers came about their decision. I just don't
necessarily think that a question like "How does RPG do it?" was necessarily
the correct one when developing support for stream files. As you say, RPG
didn't support stream files so the compilers would have done better to look
at a language which "did" have stream file support and emulate that. But,
looking at the development of VARPG through a rear-view mirror will always
provide distorted views. I accept your charge, and I wont deny it. The
F-specs work, and that is what matters at the end of the day. VARPG native
support is here, and it isn't going to go away. I wouldn't suggest that it
should. I just don't think RPG needs F-spec support for stream files simply
because VARPG has it.
 
<snip>
Interestingly you never made the point (as Booth did) that RPG IV should
provide native support - something that many users have requested by the
way.  But history says that that is the natural way things should perhaps
have gone.
</snip>
 
That is because I don't think RPG needs to provide native support. As we
already have open() and her sisters I think developing something like that
would be a waste of development time and effort - unless it was as part of a
larger project such as native support for XML, HTML, or PDF generation. Now
I could buy into that.
 
<snip>
One last point that everyone seems to have missed.  If you _want_ to handle
files in VARPG via open() etc. - there is nothing to prevent you from doing
so.  Indeed many VARPG users do that to gain greater control over files than
the native interface support provides.
</snip>
 
No, we didn't miss it. both Marco, and myself have talked about it. But it
does make you wonder why the compilers developed F-spec support for handling
stream files when they could have simply provided extensive documentation
and prototype copy source for using open(), etc. As you say, it allows the
programmer to gain greater control over files - and it is all already there
for free! I mean talk about re-inventing the horse shoe. :-)
 
I know I'm probably going to have to circle my wagons or surrender soon. But
you know, this is a stimulating debate and it is going to be at the heart of
RPG enhancements for the next few years. At our shop we are using XML in
interfaces more and more. It is not going to go away, and we need good
healthy debates about how RPG/VARPG should interact with the file (and
other) systems. My point of view at the moment is that the unix system
interface does a really good job for RPG. It is simple and easy to use. Do
we really need native support?
 
Cheers
 
Larry Ducie
 
 
 
 
 
 
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