Re: Data Structure Array Lookups

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

Hi Stephen,

The %lookupxx() BIFs and the LOOKUP op-code have never been enhanced to 
understand how to search an array of qualified data structures.  I've 
complained about this before, but IBM just laughs at me.

The bsearch() API can be used -- but it might be overkill.  bsearch() 
does require that the array is sorted, since it does a binary tree 
lookup (as does %lookup if you've specified ASCEND or DESCEND on the array).

If you don't need the performance boost of a binary tree lookup, you 
might write a simple loop:

nWrkIIT = 0;
for x = 1 to nIIT;
   if a57832(x).IIT.I1$IIT = xIIT;
     nWrkIIT = x;
     leave;
   endif
endfor;

Granted, that might get ungainly to code if you need to repeat the code 
in many places -- so just throw it into a subprocedure, then you can have:

    nWrkIIT = findIIT(a57832: 1: nIIT);

Of course, you could just just overlaid arrays or something like that 
instead -- but there are many advantages (IMHO) to qualified DS arrays, 
and I personally don't mind writing a quick lookup routine.

Coyle, Stephen F. wrote:
> Hi All, 
>
> If I have a data structure coded as below, how can I do a lookup against
> a subfield? 
> I1$IIT is a subfield of the IIT field. I'd like to find the element that
> matches I1$IIT. 
>
> The compiler didn't like mine:
> nWrkIIT = %Lookup( xIIT:a57832.IIT.I1$IIT:1:nIIT )  ;
>
> D a57832          DS                  QUALIFIED DIM(20)   
> D  IIT                                LikeRec(I57832)     
> D  PMcu                               Like( KgMcu   )     
> D  PSub                               Like( KgSub   )     
> D  PObj                               Like( KgObj   )     
> D  OANI                               Like( GlAni   )     
> D  OAA                                Like( GlAA    )     
>
> Or is this data structure not defined correctly?
>
> Thanks....
>
> - Steve