Re: Exporation and Encapsulation

["Larry" <Larry_Ducie@xxxxxxxxxxx>]

Hi Kurt,
 
<snip>
In regard to the Export/Import feature, maybe if IBM allowed us to
specify the Const keyword along with the Export keyword, then subsequent
modules would have access to the value w/o being able to change it (much
like procedure calls).
</snip>
 
I suppose that would be nice. It would give us the ability to have read-only
access to data items in other modules. I suppose the benefit there would be
the fact that the import/export is still within the program object. I can't
imagine that it would be easy to do though. The data in all copies would
have to be updated every time the value was changed in the originating
module. This is easy when each import simply references the address of the
export. Not so easy when they're all copies.  
 
<snip>
While I have used encapsulation, I think if the Export/Import feature
were further expanded upon, it'd be a really nice tool.
</snip>

The use of data item imports/exports AND encapsulation via sub-procs could
hold a partial solution:
 
You could have a scenario where you can import/export your data items
accross modules within the same (service) program object, but not beyond.
Then, for all data items that need to be exported beyond the service program
object you would create getter sub-procs.
 
You know, I'm still not sure about the idea of modules exporting data items,
even to other modules within the same program object. It seems to me that
modules should be re-usable, and having a module that has explicit imports
from other modules seems to fly in the face of that. However, I am willing
to be convinced. I mean, I can see the use of generic imports in a utility
module, that allows the behaviour of the module to change depending upon the
other modules it is bound to (resolving it's imports to a variety of module
exports).
 
Maybe the real solution would be the ability to specify the level of export
for a sub-proc or data item. Something like:
 
EXPORT - the current value, and the default
EXPORT(*PGM)
EXPORT(*SRVPGM)
EXPORT(*ACTGRP)
EXPORT(*JOB)
EXPORT(*BND) - same as EXPORT  
 
Hmmm...
 
Food for thought.
 
Larry Ducie