CBOR

Summary

The session focused on the progression of Extended Diagnostic Notation (EDN) documents, specifically draft-ietf-cbor-edn-literals. Carsten Bormann provided a status update on the transition of EDN from an update of existing RFCs to a standalone specification with normative ABNF. The group discussed recent technical changes including raw strings and debated the expansion of comment syntax to improve usability and compatibility with JSON-based tools. A timeline was established for a second Working Group Last Call (WGLC) in April 2025.

Key Discussion Points

Status of EDN Literals

Carsten Bormann presented the history and current status of draft-ietf-cbor-edn-literals.

Restructuring: Following IESG feedback, the document was changed from an "update" to RFC 8949 and RFC 8610 into a standalone document incorporating all EDN definitions.
Objectives: EDN is intended for diagnostics, test vectors, configuration files, and documentation (specifically fitting within 69-column constraints).
Recent Changes: Version -21 includes ABNF for integrated parsers using raw strings for hex and base64 byte strings.

Raw Strings and Usability

Carsten Bormann highlighted the addition of raw strings (using backquotes) to avoid "quoting hell" and backslash-processing overhead.
The implementation allows for any number of backquotes as delimiters to wrap strings containing backquotes.

Comment Syntax (Issue 82 / PR 83)

A significant portion of the meeting was dedicated to proposed changes to comment syntax in draft-ietf-cbor-edn-literals.

Current state: Inline comments use slashes / comment / and end-of-line (EOL) comments use the hash #.
Proposed EOL comments: There is interest in adding // as an EOL comment delimiter to align with common JSON extensions (JSONC, JSON5). Carsten Bormann noted this creates a minor non-backwards compatible change where empty inline comments // would no longer be valid.
Proposed Inline comments: Discussion regarding adding C-style /* ... */ comments.
- Christian Amsüss argued for an asterisk-based form to allow URLs (which contain slashes) to be included in comments without breaking syntax.
- Carsten Bormann observed that while he personally finds the asterisk syntax less than ideal, it facilitates copy-pasting from other text formats like JSONC/JSON5.
- Вадим Гончаров and Carsten Bormann discussed historical precedents (Pascal, PL/I) for such delimiters.
Sense of the Room: There was general sympathy among participants for including /* ... */ and // style comments to improve developer experience, despite minor compatibility impacts.

EDN Extensions

The group discussed draft-ietf-cbor-edn-e-ref and future extension possibilities.

Current Extensions: The "E" and "REF" extensions are already being used.
Future Ideas: Carsten Bormann mentioned potential extensions for FLOAT (non-finite values), BOTH (providing both raw and semantic representations for verification), and Base32 conversions.
Strategy: Ira McDonald suggested avoiding a proliferation of small documents. Christian Amsüss suggested batched updates similar to how CDDL extensions have been handled in the past.

Decisions and Action Items

Decision: The working group will move forward with adding // (EOL) and /* ... */ (inline) comment syntax to draft-ietf-cbor-edn-literals.
Action Item: Carsten Bormann to update the draft and associated implementation tools with the agreed-upon comment syntax.
Action Item: All participants are encouraged to review their existing EDN collections to verify if the non-backwards compatible change regarding // impacts their use cases.

Next Steps

Timeline:
- Merge existing Pull Requests and close relevant issues by the end of March 2025.
- Initiate a second Working Group Last Call for draft-ietf-cbor-edn-literals in April 2025.
- Aim for IESG submission by May or June 2025.
Mailing List: Christian Amsüss will take the detailed overview of string types to the mailing list for further discussion.

Reference Materials:

Slide Deck: EDN

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