Re: sel and seq records

[Andrew Johnson <anj@aps.anl.gov>]

Hi Dirk,

On 11/27/2013 07:09 AM, Dirk Zimoch wrote:
> I have added pp(TRUE) to some fields, so that the behavior is similar to
> the calc record. The following fields are affected:
>
> sel: SELM, SELN
>
> seq: SELM, SELN, DO1, DO2, ... DOA

I don't want to make this kind of change to record behaviour in a 
bug-fix release (3.14.12.4), although I will consider them for the 3.15 
branch.

The seq record only has one field marked as pp(TRUE), the VAL field, and 
the prompt text for that field is "Used to trigger", so I suspect the 
implicit pp(FALSE) setting on the other fields was a deliberate design 
decision by the author. I'm currently inclined to change the sel record 
but not the seq, but would appreciate comments from anyone else about 
this idea (which makes the two behave differently so I'm not really 
convinced that's right either).

The disadvantage of making fields pp(TRUE) is that a client then has no 
choice about processing the record, whereas for a pp(FALSE) field a 
client can always follow up with a put to the PROC field (there's a 
feature which display managers haven't implemented yet AFAIK). A 
database designer can also insert an ao record in front of the relevant 
fields of the seq record with a PP or NPP output link to change the 
behaviour one way or the other, so there are workarounds to a field 
having the wrong pp() setting.

- Andrew
--
Advertising may be described as the science of arresting the human
intelligence long enough to get money from it. -- Stephen Leacock