Re: Data Structure redefinition

[bmorris@xxxxxxxxxx]

>From: "M. Lazarus" <mlazarus@ttec.com>
>Sent: Wednesday, November 01, 2000 3:00 PM
>
>    Is it possible to have a basing pointer on a DS subfield?  If not,
why?
>
>    What I would effectively like to do is "redefine" DS fields in another
> DS.  When dealing with outputting multiple "formats" of the same data, it
> would be much easier to have multiple DS's with different layouts, but
have
> the subfields point to the same data.
>
>   This would eliminate multiple EVALs and would probably be a lot more
> efficient, if it can be done.
>
>
> Example:
>
> D    DS
> D A            LIKE( AA )
> D B            LIKE( BB )
> D C            LIKE( CC )
>
> D    DS
> D D            LIKE( AA ) BASED( D@ )
> D         6    INZ( 'Space1' )
> D E            LIKE( BB ) BASED( E@ )
> D         6    INZ( 'Space2' )
> D F            LIKE( CC ) BASED( F@ )
>
> C         EVAL D@ = %Addr( A )
> C         EVAL E@ = %Addr( B )
> C         EVAL F@ = %Addr( C )
>

Mark, it's impossible (in RPG at least) to have a
data structure whose subfields each have their storage
somewhere else.  RPG data structures always have contiguous
storage.

(I don't know of any language that would allow you to
have two structures "ABCDEF" and "AB CD EF" where the
ABs, CDs and EFs are actually the exact same storage.)

Barbara Morris


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