Re: RPG Cycle

[fkolmann@xxxxxxxxxxxxx]

OK.  Still the RPG cycle is 'supposed'  do handle all READS WRITES UPDATEs in 
hidden
manner.
The fact that the file IO in NOT specifically coded for is what confuses most
beginners.
Anyhow recently I had this case,
Order Header File (Keyed by Order number)
Order Detail File  (Keyed by Order Number,  Line Number)
Invoice Detail File (Keyed by Order Number , Line Number)
I asked a programmer to use Control breaks and MR to find
mismatched Headers and also mismatches between the Order Lines and Invoice 
Lines,
we had a problem using MR to find orphaned Invoice Detail Lines, we had to 
write 2
programs
the first using the Header as a primary file, the second used the Detail as the
Primary file.
Perhaps you have a suggestion how we can do this with one program.

pcunnane@learningco.com wrote:

>      It quickly becomes a hair-splitting excercise, but splitting hairs is
>      sometimes the most effective way to understand something in detail.
>
>      When you create an RPG program, the compiler inserts the cycle code.
>      It's always there.  If you don't have a primary file, chunks of the
>      cycle don't get executed (such as primary input, total output), but
>      they are still there.  When the mainline of your code executes, it is
>      the first cycle of the detail time calculations.  To prevent your
>      program from looping through the cycle indefinitely, you have to set
>      LR or execute a RETRN/return.
>
>      Coding H NOMAIN prevents the cycle code from being included in the
>      program at all.
>
>      To say that every programming language has a cycle of sorts is to
>      misunderstand how the cycle works.  There is no way to get a C program
>      to constantly repeat its main() routine; you have to code a loop
>      within main().  RPG will happily repeat the mainline C-specs until it
>      finds an explicit exit.
>
>      Peter Dow:  I loved your non-primary cycle example!
>
>      ____________
>      Paul Cunnane


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