Re: Field record relation indicators (and lookahead)

Hello all:

On those rare occasions when you need look-ahead fields, I think that it
would be easy enough to code in a SPECIAL device subroutine.

Regards,
Brian Lawson
HJM Systems, Inc.
blawson@hjmsys.com

At 12:10 AM 4/5/98 +0000, you wrote:
>Hans,
>
>At 10:31 AM 4/1/98 -0500, you wrote:
>>Mark wrote:
>>>>If you need some sort of lookahead on sequential reads to an externally
>>>>described file, you could probably manage nicely using externally
>>>>described data structures and READ into DS.
>>>
>>> Wouldn't you still have to define the from and to positions in the
>>>look-ahead area?
>>
>>No.  The technique I described works like this:  You define 2 externally
>>described data structures
>>(called, say, CURREC and LOOKREC) from the file you want to read from, using
>>PREFIX to rename
>>all the fields in one of them.  Keep the current record in CURREC and the
>>lookahead record in
>>LOOKREC.   To start reading, do:
>>
>>       C                          READ        FILE              CURREC
>>       C                          READ        FILE              LOOKREC
>>
>>To read the next record, do:
>>
>>       C                          EVAL        CURREC = LOOKREC
>>       C                          READ        FILE              LOOKREC
>
> This method doesn't stack up well when using level breaks.
>
> -mark
>
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