RE: rpg400-l-digest V1 #239(except vs update and modular design)

> -----Original Message-----
> From: Pete [mailto:prmoore@mail.globalnet.co.uk]
> Sent: Wednesday, September 29, 1999 1:04 AM
> To: rpg400-l@midrange.com
> Subject: Re: rpg400-l-digest V1 #239
> 
> 
> James
> 
> Obviously no one is creating 150 page programs anymore, and code that
> updates data fields is concentrated in one place? I have 
> needed O-specs
> for the last 6 years, I can't see me adopting them now. 
/*                     Titanic Snip                                    */

Ok, I've taken the bait.

1.  It's easy to write a simple report that produces a 150 page listing,
especially if you count the cross reference.  It's also very easy to make
that "monster" easy to read and maintain.  Modular design is based on the
idea of reducing a task to "atomic" subtasks (always wanted to use "atomic"
that way) and then bolting them together as a bunch of black boxes.  If you
design your programs that way, you or anyone else who does maintenance on
them may never need to look at the low level code.  Whether you do it with
procedures, separate programs, or subroutines that use global variables
doesn't matter too much.  If the task is big, there's going to be a lot of
code involved.  It's also easy to write "modular" programs that are
impossible to extend or maintain.  I've probably written some, and I know
I've had to do maintenance on some written by others.  If the design is bad,
it doesn't matter what philosophy the designer followed.

2.  Exception output has some legitimate uses.  If you're updating a few
fields in a large record format in a batch process on a large file, you can
get a performance boost by using exception output.  Obviously the best
performance comes from using sequential input and output to a new file that
replaces the original (using write), but you don't always have that luxury.


3.  I like O specs for printer output in a lot of situations.  For a simple
report that has a heading and detail data in columns, O specs are just as
easy to understand as print files and very simple to write and maintain. You
can't do a lot of fancy formatting, but it's a question of using the right
tool for the job.  
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