RE: Help! Boss wants to know why ILE?

Barbara,

I have to agree that the multiple levels of privacy is one of the key reason to
use ILE.

Unlike modularity, you simply can't do it with OPM style program.

One question, what are you considering "public" for a program? Just the
program's interface or am I
missing something else?

Thanks,
Charles

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Barbara Morris
Sent: Monday, April 23, 2007 10:04 PM
To: rpg400-l@xxxxxxxxxxxx
Subject: Re: Help! Boss wants to know why ILE?

With programs, you have only two levels of privacy:
1. Private to the program
2. Public

With procedures, modules, service programs, programs, you
have more levels:
1. Private to the procedure (available only to that proc)
2. Private to the module (available to all procs in the module)
3. Private to the service program (available to all procs
in the srvpgm)
4. Public

Using the additional levels of privacy don't just make your
applications "better" in some academic way. They can
sometimes reduce maintainance time by orders of magnitude.
Want to add or change a parameter? If it's a local
non-exported procedure, just do it, and possibly change all
the callers in the module, depending on your parameter keywords.
Whatever changes you made, you only have one module to recompile.
There's no need to investigate to find all the callers, so
they can be recompiled, and to worry that maybe someone is
calling your program using a variable. There's no need to
test everything just in case some caller was missed; you
should be able to focus testing on just that one module.

As a rule of thumb, the more public a routine or data
structure layout is, the less freedom you have to redesign
the parameters for the routine, or the data structure layout.
The less freedom you have to do something, the more time it takes.

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