Darren,
In this case, the global data appears to be central to the purpose of the
application and I don't see a need to "avoid that where possible".
It sounds like "data passing" may be reducing code maintainability and,
if that is true, then I would go for maintainability.
-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of darren@xxxxxxxxx
Sent: Tuesday, July 24, 2012 9:47 AM
To: RPG programming on the IBM i / System i
Subject: Re: Sub procedures and growing parameter lists
I think I have the most problem around trying to keep I/O from happening multiple times needlessly. For example, my program might print a part label and a box label with similar information. To prevent me having to go to the order file multiple times, I read the order part information at a high level in the program, and I have to pass that through the sub procedures until its time to actually print the two labels. I could make the information global, but I try to avoid that where possible.
* For a simplied example:
ECL1=$GetOrder(Order#)
EIX1=$GetXREF(ECL1)
callp $PartLbl(ECL1 : EIX1)
populate label data
callp $PrtPartLbl(LblData)
callp $BoxLbl(ECL1 : EIX1)
populate label data
callp $PrtBoxLbl(LblData)
* is better than:
callp $PartLbl(Order#);
ECL1=$GetOrder(Order#)
EIX1=$GetXREF(ECL1)
populate label data
callp $PrtPartLbl(LblData)
callp $BoxLbl(Order #);
ECL1=$GetOrder(Order#)
EIX1=$GetXREF(ECL1)
populate label data
callp $PrtBoxLbl(LblData)
From: Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>
To: RPG programming on the IBM i / System i
<rpg400-l@xxxxxxxxxxxx>,
Date: 07/24/2012 11:21 AM
Subject: Re: Sub procedures and growing parameter lists
Sent by: rpg400-l-bounces@xxxxxxxxxxxx
hi Darren,
It's hard to say whether you're doing it "wrong," since I have only a high-level description of what you're doing.
In my experience, when a subprocedure has too many parameters, it usually indicates that the procedure is trying to do too many things.
IMHO, a subprocedure should just do one thing -- and when the time comes to do the next thing, a separate procedure should be used. However, it's very difficult (for me, at any rate) to describe what constitutes "one thing."
And, there are certainly cases where a lot of data is required for just one thing.
Nesting data structures inside other data structures is a relatively simple solution -- but I find that when I do that, I have to work hard to keep the DS names short -- otherwise, it becomes very difficult to deal with the nested DS, the names quickly become too long.
On 7/24/2012 9:40 AM, darren@xxxxxxxxx wrote:
I have been using sub procedures exclusively in my code for about 3
years now. One things that I continually have trouble with is a
growing number of parameters that I pass around. If one procedure
gathers a bunch of
data
and a couple different sub procedures need to process with that data,
all of that data has to be declared and passed. I'm talking about
data structure data, so lumping the variables into a data structure
would mean data structures within data structures. I've done this
data structure nesting before and it looks confusing when I come back
to it later. What
I
find myself wishing for is variables global to the current call level.
This could be accomplished with local subroutines I'd guess.
Am I doing it wrong?
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