Re: DS argument list for i/o vs. listing the arguments at the i/o statement

And to counter Brian's counter ... <grin>

Using the DS often forces you to copy the data into the DS elements. Using a list of key fields does not require this making it easier to use a key from multiple sources without copying. Also it permits the use of constants, literals, and anything else that a CONST parameter construct can handle - so just all round more flexible.


Jon Paris

On Aug 18, 2021, at 3:20 PM, Brian Parkins <goodprophet.bp@xxxxxxxxx> wrote:

No strong feelings either way, just a counterpoint re. maintenance.

For (1) the DS will be defined in one place and can be used throughout the code, (CHAIN, READE, etc.) If the key structure were to change - or a coding error encountered - only one place to correct. No need to search for the in-line definitions. (Same philosophy as when using Named Constants - define in one place only.)

I agree (2) is more readable.

Brian.

On 18/08/2021 14:24, Alan Cassidy wrote:

A question about using a data structure key list for record i/o vs. listing the keys in the i/o line.

(1) chain %kds( CustkeysDS ) Custfile ;

--versus-

(2) chain ( CustType : CustNbr ) Custfile ;

I like the #2 syntax better, for showing the actual key value arguments inline, at the sttement itself, as more maintenance-friendly, even if the arguments' field names are from the file itself. I'm mostly wondering if anybody knowss whether there are any performance differences?

--Alan Cassidy

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