General approach for "unsupported features" in exporters

[erikbosch]

Now we are implementing struct support, and we have a proposal to add stringsize. In some exporters (like Yaml/JSON/CSV) adding support is relatively straightforward, but what to do in others? Maybe not a big problem as long as we do not use the concept in the standard catalog, but what if we use them in standard catalog?

Documenting how the features are handled in each exporter should be minimum requirement, but what more? Some ideas:

• If we use a feature in standard catalog (e.g. struct or stringsize), then none of the "official" tools (i.e. not contrib/obsolete) shall give an error
• But is ok that exporters ignore certain features, in some cases it might be impossible to support the feature in target language/format
• If important features like datatype (e.g. struct) can not be supported a warning shall be given stating name of the signal is ignored.
• If less important features are ignored (like stringsize), an info message shall be given.

[erikbosch]

Meeting notes:

• Nick - do we need an "unsupported features" file to list what is supported
• Stephen - If tooling is important - then why not support all tooling.
• Krishna - if so I would be very careful of scope of tools
• Stephen - We may get problems if tools not are updated.
• Neil - Could be good if output format is defined