YAML versions

[VladimirAlexiev]

Which YAML versions should YAML-LD support?

• relevant versions could include https://yaml.org/spec/1.0, https://yaml.org/spec/1.1, https://yaml.org/spec/1.2.2/
• But YAML is pretty stable: 12 years between 1.2.1 and 1.2.2 (https://yaml.com/blog/2021-10/new-yaml-spec/), so maybe just the latest one is relevant
• 1.2.2 says it's just an editorial rewrite of 1.2.1, but some tags have been withdrawn, and more are pending withdrawal (eg for datetime literals)

[ioggstream]

MUST 1.2.2

MAY some sensible features of YAML 1.1

[VladimirAlexiev]

@ioggstream wrote

In YAML 1.2, all valid JSON parses to valid YAML. When discussing with YAML folks, they told me that this cannot be guaranteed for YAML 1.3

"Cannot be guaranteed" is troubling. But also I cannot imagine how that can be, if YAML 1.3 is backward compatible with YAML 1.2.2. Should we worry about this potential future YAML 1.3 version?

[ioggstream]

"Cannot be guaranteed" is troubling.

Theoretically, you must parse YAML document with a YAML parser, and a JSON document with a JSON document. iiuc trouble should arise only when there's a JSON document that cannot be mapped to a YAML representation graph.

Should we worry about this potential future YAML 1.3 version?

My opinion is that , given the implementation base, this won't happen. OTOH in mediatype we are just relying on the fact that JSON data and document structures are a subset of YAML's ones.

[ioggstream]

I'm stubbing a PR based on the YAML work:

• this document is based on YAML 1.2.2
• the mediatype registration is related to YAML in general and not on a specific version
• people that cares about version, SHOULD start their documents with %YAML X.Y

[VladimirAlexiev]

I like the decision to fix the version to 1.2.2, so I'll close this. But @ioggstream I have some comments on the above commit.