Re: How to reconcile conflicting array documentation

Rick.Chevalier@xxxxxxxxxxxxxxx wrote:

I'm trying to add a prerun-time array to a program for the first time in
many years. After looking up the the nuances for a prerun-time array I
added the appropriate F and D specs. That's where the trouble began. I
need to add an alternating array which it sounds like I can do from the
documentation on coding a prerun-time array shown below from the RPG
Reference manual. However, the ALT keyword doesn't play nice with the
other keywords I need, specifically FROMFILE. The ALT keyword
documentation specifically says it cannot be used with FROMFILE.

You use FROMFILE to list the first array and you use the ALT keyword to list the second array. Say your file has lines like this:
Sally London
Jack Amsterdam
Anne Boston

Then you would code
D aName S like(NAME) DIM(1200)
D FROMFILE(myfile)
D aCity S like(CITY) DIM(1200) ALT(aName)

But I prefer Booth's method. You would code FROMFILE on the aArray array. Besides being easier to understand (for me, at least), this method allows you to have data for more than two arrays.

D ds
D aArray dim(1200) FROMFILE(myfile)
D aName like( NAME ) overlay(aArray)
D aCity like( CITY )
D overlay( aArray: *next)
D aAge like( AGE )
D overlay( aArray: *next)
D aPhone like( PHONE )
D overlay( aArray: *next)

Then you can use lookup on either the aName, aCity, aAge or aPhone arrays.

i = %lookup('Jack' : aName);
msg = 'Jack lives in ' + aCity(i);