Experimental Physics and
Industrial Control System

"Johnson, Andrew N. via Core-talk" <core-talk at aps.anl.gov> · Sun, 29 Mar 2020 00:26:25 +0000

Allowing multiple filters to be used chained together is most definitely something we want to support, although in most cases they would probably be different filters, say array to extract one value followed by a deadband filter say, possibly with a time stamp filter as well. Repeating the same kind of filter seems less necessary, but given that we can support it at no cost I don’t see why we should try to prevent it.

I understand that some JSON parsers won’t handle duplicate keys, is that what concerns you?

- Andrew

-- 
Complicity is easy, Simplexity takes real work

> On Mar 28, 2020, at 2:45 PM, Ben Franksen via Core-talk <core-talk at aps.anl.gov> wrote:
> 
> The array filter test (modules/database/test/std/filters/arrTest.cpp)
> creates "double" array filters that look like:
> 
>  {"arr":{},"arr":{"s":x,"e":y,"i":z}}
> 
> Apparently this is interpreted by EPICS base to mean two array filters
> in succesion, first the left, then the right.
> 
> According to the JSON standard this is allowed. But is it a good idea?
> Are there practical use cases? (The test where I've seen this doesn't
> count IMO).
> 
> Cheers
> Ben
> 
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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System