Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Wed, 29 Sep 2010 12:49:15 -0500

Hi Russell,

On Wednesday 29 September 2010 12:30:27 Redman, Russell wrote:
>
> Can I make a suggestion that the length of the CALC field be fixed by
> the designer, but configurable through a new field, perhaps called CLEN.
> The default value of CLEN would of course be 40 if not otherwise
> specified.

I would prefer to automate the size adjustment based on the expression 
actually used.  I don't think it will be too hard to support a variable length 
string field type, but it's not going to be backwards compatible with existing 
code so it couldn't be added to the 3.14 series.

I accept all your points about the clunkiness of the existing CALC record 
type, my purpose with this discussion was to suggest that we can alleviate 
some of the length issues in what may be the last 3.14 release by just making 
the string bigger, now that we have long string support in Base.

> 5) Way back, around 2004 I think it was, Tim Mooney helped me with a
> with a customization of the postfix and calcPerform routines that
> allowed expressions like MAX(A,B,C), which are much more compact than
> MAX(A,MAX(B,C)).  These never made it into base because they broke
> expressions like A?B, which I never used because they leave
> unpredictable numbers of items on the stack, but which turn out to be
> common in some applications.  If the CALC record is reworked, can I
> suggest that this issue be re-examined at the same time?

Variable arguments are already available for the MAX, MIN and FINITE and ISNAN 
functions, they finally arrived in R3.14.10 as a result of your prompting, 
although using different code.

- Andrew
-- 
If a man is offered a fact which goes against his instincts, he will
scrutinize it closely, and unless the evidence is overwhelming, he will
refuse to believe it.  If, on the other hand, he is offered something
which affords a reason for acting in accordance to his instincts, he
will accept it even on the slightest evidence.  -- Bertrand Russell

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System