RE: Data Structure Constant

I put the request in and so far see no way of having people sign onto it like a petition. So I suggest putting one out there yourself as well. Not sure how the IBM suggestion process works.

https://www-912.ibm.com/r_dir/ReqDesChange.nsf/Request_for_Design_Change?OpenForm

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Bruce Guetzkow
Sent: Tuesday, April 21, 2009 9:01 AM
To: rpg400-l@xxxxxxxxxxxx
Subject: RE: Data Structure Constant

Kurt:

<snip>
I have a data structure and I'd like for its contents to never be changed, enforced by the compiler. How do I do this?
</snip>

Just wondering...have you submitted a formal request for this to IBM? I've thought of another scenario that seems to apply...

Consider the following code:

dou forever;
exfmt screen;
select;
when fkey = F3;
leave;
when fkey = enter;
prcenter();
endsl;
enddo;

The above is just a rough sketch of a way to process screen input: Read a screen "forever", processing the enter key each time it is pressed, exiting when F3 is pressed.

In order to do this "forever" must be a Boolean expression or indicator. Normally I define a standalone variable (type "N") and set the value to *OFF. I never change the value of the field "forever". However, like your scenario, someone could come along at a later date, not understand how "forever" is used, and set "forever" to some other value (like *ON). I'd like to define "forever" as a constant, but then I can't use it in the "dou" statement. Having a READONLY keyword which can be used against DS or standalone field would be ideal.

Of course, since any Boolean will do, you could always do something like: "dou 'A' <> 'A'", but that seems less obvious.

If you've already submitted a request, is there a way for us to add our support?

Thanks in advance,
--Bruce Guetzkow