RE: Benefits of Sub-procedures

["Bill Hopkins" <BHopkins@xxxxxxxxxxxxxxxxxxx>]

"fire is useful" lol




Scott Klement <klemscot@xxxxxxxxxxxx>
Sent by: rpg400-l-bounces@xxxxxxxxxxxx
10/23/2003 11:45 AM
Please respond to RPG programming on the AS400 / iSeries

 
        To:     RPG programming on the AS400 / iSeries <rpg400-l@xxxxxxxxxxxx>
        cc: 
        Subject:        RE: Benefits of Sub-procedures



> I must be missing something.  While I agree with the use of procedures,
> modules and service programs I don't see them reducing the number of
> objects.
>
>                Module --> Service Program --> Application = 3 objects
>                                                                or
>                Module1 \
>                Module2  --> Service Program --> Application = 5 objects
>                Module3 /
>
>                                                                vs.
>
>                Bound program ---------------> Application = 2 objects
>                                                                or
>                Bound program1 \
>                Bound program2  -------------> Application = 4 objects
>                Bound program3 /


I assume you mean "bound modules?"  In which case, you've got a big
problem here.   Every time you change the code in a module, you have to
search out and re-bind every program that uses that module.   That's a
major maintenance nightmare for a shop like mine where there are 5000
programs.

The original poster asked why not create programs instead of service
programs, still making them modular, but calling programs instead of
subprocedures.   That changes your diagram to:

                 Module1 \
                 Module2  --> Program --> Application = 5 objects
                 Module3 /

Which is the same number of objects as the service program.   But, it's
got a big disadvantage over a service program, doesn't it?   It's only got
one callable routine -- the program itself.   A service program can have
many subprocedures that you can call.

So, therefore, for each subprocedure in your service program, you have to
create a separate program.   My average service program probably has about
10 routines in it.   Therefore, if I used programs, I'd have about 10
times as many objects as service programs.

Then, when you add to that the performance difference, and the inability
to use the signature "level checking" that service programs give you, etc,
etc, etc...  you start wondering why someone would ever argue things the
other way?

What's the advantage of using separate callable programs instead of
service programs?   The advantage to callable programs is that your 90
year old programmers (who haven't yet agreed that fire is useful) are able
to use the callable programs.
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