AW: VSS instantiation discussion

Hello,

As usual (well most of the time ☺ ) what Ulf says makes sense.

First two points I would agree, however for the last one
“All metadata from a node in YAML MUST be preserved in the translations, except for instantiation metadata that MUST not be present. “

I am not so sure. Because if exporting to “dumb” formats like .csv it might not even be possible to do that in a sane way. Personally I doubt the usefulness of CSV export anyway, but since some people use it/need it, such things should not be forbidden.

I think we should formulate as guidelines
  “All metadata from a node in YAML SHALL be preserved in the translations”

For instantiation it is really the “instances are a VSS feature” vs. “instances are just syntactic sugar” we started yesterday . In the second case (I feel we are leaning that way currently)
“Instantiation metadata SHALL be processed and expanded so the output represents a flattened VSS tree”


Then I feel for “common” output formats we have today (like JSON, CSV), we should find some middle ground between saying “this IS VSS” and “this is just random code, please ignore”. We can say “When exporting to JSON/CSV, the canonical JSON/CSV output format should look like this”, because I think even following the 3 rules you laid out, there are probably many JSON formats that can adhere to them.

Generators we are still “playing” with we can just mark as experimental


Mit freundlichen Grüßen / Best regards

Sebastian Schildt

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Von: Ulf Bjorkengren <ulfbjorkengren@geotab.com>
Gesendet: Dienstag, 7. Juli 2020 21:20
An: public-automotive <public-automotive@w3.org>
Betreff: VSS instantiation discussion

Regarding the VSS instantiation discussion I think we need to establish a few ground rules, in order to not get lost. Below is my attempt on a few rules for such a list.

- YAML MUST unambiguously specify the path to a leaf node.
- Translations from YAML to other formats MUST preserve the path definitions.
- All metadata from a node in YAML MUST be preserved in the translations, except for instantiation metadata that MUST not be present.

Regarding Gen2 and JSON I would say that Gen2 is agnostic to what format the VSS tree uses. Gen2 uses JSON as payload format, but that has nothing to do with what format the VSS tree is represented in. In the Gen2 impl project the VSS tree is represented in the native C format, as an example.

BR
Ulf
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Ulf Bjorkengren

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