Defining "Meta overlay"-like properties that are the same (duplicated) across all languages

[swcurran]

We need a way to have a number of "Meta"-like entries that are language agnostic. As currently defined in the OCA Standard, and managed in the OCA Source spreadsheet, "Meta" entries (name/value pairs) are multilingual and thus the names are duplicated for each language. However, there are a number of values for Meta names that are the same across all languages. How can we manage that?

Two ideas for that:

• In the "OCA Source", define a way to have unilingual Meta elements that are automatically added to all language specific Meta Overlays (e.g. in the Capture Base tab in the spreadsheet, have a pair of columns for Meta, same as in the language-specific tabs).
• Have a new overlay that is unilingual and equivalent to Meta.

I think this is a generally useful feature and belongs in the OCA Core. In the Aries community, we could address it using a custom overlay that is defined within the community.

Example use cases:

• If an OCA Bundle is being used with a set of languages, is there specified way to indicate the default one to use? Should that be a part of the OCA specification?
• It would be good in the AnonCreds Verifiable Credential use case to have a reference in the Meta layer to the Schema and CredDef for the credential type.
• We would like to designate a given credential type as a "test" credential.

[swcurran]

Realizing that since the Meta Overlay is a multilingual overlay, having default language there may not be ideal, as it would be repeated for each language, but needs to have the same value across all instances.

We could put it in our Aries specific "Branding Overlay", as it applies to the entire credential but is not multilingual. However, it still feels like it is an "OCA Core" type item, so would welcome HCF guidance on this one.

[swcurran]

Updated the title and description (initial comment) for this issue to be more general.

[swcurran]

Another idea -- could such attributes go in the Capture Base. It is exactly what we're looking for -- language agnostic metadata about the data structure (credential, in our case).

Are we permitted in the spec to extend the Capture Base with additional name/value pairs?

[pknowl]

@swcurran My suggestion would be to drive that through the Capture Base with a "default_language" attribute. That provides an opportunity to spin a default language through the entire bundle, as all Overlays rely on a Capture Base.

I haven't discussed this potential solution with the OCA technical experts, but conceptually, it sounds reasonable.

I have another potential solution on this topic, but I want to consider it further before bringing it up in this thread.

[pknowl]

@swcurran I spoke to @mitfik about default language. He confirmed that it is not the responsibility of OCA to set a default language. The interface which parses the bundle is responsible for that.